Search Results

Search found 841 results on 34 pages for 'frequency'.

Page 6/34 | < Previous Page | 2 3 4 5 6 7 8 9 10 11 12 13  | Next Page >

  • How would i down-sample a .wav file then reconstruct it using nyquist? - in matlab [closed]

    - by martin
    This is all done in MatLab 2010 My objective is to show the results of: undersampling, nyquist rate/ oversampling First i need to downsample the .wav file to get an incomplete/ or impartial data stream that i can then reconstuct. Heres the flow chart of what im going to be doing So the flow is analog signal - sampling analog filter - ADC - resample down - resample up - DAC - reconstruction analog filter what needs to be achieved: F= Frequency F(Hz=1/s) E.x. 100Hz = 1000 (Cyc/sec) F(s)= 1/(2f) Example problem: 1000 hz = Highest frequency 1/2(1000hz) = 1/2000 = 5x10(-3) sec/cyc or a sampling rate of 5ms This is my first signal processing project using matlab. what i have so far. % Fs = frequency sampled (44100hz or the sampling frequency of a cd) [test,fs]=wavread('test.wav'); % loads the .wav file left=test(:,1); % Plot of the .wav signal time vs. strength time=(1/44100)*length(left); t=linspace(0,time,length(left)); plot(t,left) xlabel('time (sec)'); ylabel('relative signal strength') **%this is were i would need to sample it at the different frequecys (both above and below and at) nyquist frequency.*I think.*** soundsc(left,fs) % shows the resaultant audio file , which is the same as original ( only at or above nyquist frequency however) Can anyone tell me how to make it better, and how to do the various sampling at different frequencies?

    Read the article

  • Why can't I connect to a Cisco wireless access point?

    - by spinlock
    I'm running a Lucid Netbook Remix on my Dell Inspiron 600m and I was not able to connect to the wireless network at the Hacker Dojo in Mountain View yesterday. There were plenty of other people on the network - MS, Mac, and Linux boxes - but my laptop would never get an ip address. I can connect to my home network, which is open, and I've never had a problem connecting at the coffee shop, which uses WPA. The Hacker Dojo is running WPA and we checked the password a number of times but got no love. Any ideas would be greatly appreciated. Additional Info: $iwlist eth1 scan eth1 Scan completed : Cell 01 - Address: EC:C8:82:FA:63:92 ESSID:"HackerDojo-gwifi" Protocol:IEEE 802.11g Mode:Master Frequency:2.412 GHz (Channel 1) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:62 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 280ms ago Cell 02 - Address: 00:18:4D:24:08:61 ESSID:"Green Zone" Protocol:IEEE 802.11bg Mode:Master Frequency:2.417 GHz (Channel 2) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:23 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 11516ms ago Cell 03 - Address: 08:17:35:32:6E:13 ESSID:"\x00" Protocol:IEEE 802.11g Mode:Master Frequency:2.437 GHz (Channel 6) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:71 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 2760ms ago Cell 04 - Address: EC:C8:82:FA:63:90 ESSID:"HackerDojo" Protocol:IEEE 802.11g Mode:Master Frequency:2.412 GHz (Channel 1) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:61 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 772ms ago Cell 05 - Address: 08:17:35:32:6E:11 ESSID:"HackerDojo-Presenter" Protocol:IEEE 802.11g Mode:Master Frequency:2.437 GHz (Channel 6) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:65 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 3308ms ago Cell 06 - Address: 08:17:35:32:7E:31 ESSID:"HackerDojo-Presenter" Protocol:IEEE 802.11g Mode:Master Frequency:2.462 GHz (Channel 11) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:88 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 1668ms ago Cell 07 - Address: 38:E7:D8:01:46:1E ESSID:"JWS_Incredible" Protocol:IEEE 802.11bg Mode:Master Frequency:2.412 GHz (Channel 1) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 500 kb/s; 54 Mb/s Quality:31 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK Extra: Last beacon: 2848ms ago Cell 08 - Address: 08:17:35:32:6E:10 ESSID:"HackerDojo" Protocol:IEEE 802.11g Mode:Master Frequency:2.437 GHz (Channel 6) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:67 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 7848ms ago Cell 09 - Address: 08:17:35:32:7E:30 ESSID:"HackerDojo" Protocol:IEEE 802.11g Mode:Master Frequency:2.462 GHz (Channel 11) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:85 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 8300ms ago Cell 10 - Address: 08:17:35:32:6E:12 ESSID:"HackerDojo-gwifi" Protocol:IEEE 802.11g Mode:Master Frequency:2.437 GHz (Channel 6) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:68 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 232ms ago Cell 11 - Address: 08:17:35:32:7E:32 ESSID:"HackerDojo-gwifi" Protocol:IEEE 802.11g Mode:Master Frequency:2.462 GHz (Channel 11) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:86 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 168ms ago Cell 12 - Address: EC:C8:82:FA:63:91 ESSID:"HackerDojo-Presenter" Protocol:IEEE 802.11g Mode:Master Frequency:2.412 GHz (Channel 1) Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s 11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Quality:62 Signal level:0 Noise level:0 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Extra: Last beacon: 7408ms ago $iwconfig eth1 eth1 unassociated ESSID:"HackerDojo-gwifi" Nickname:"ipw2100" Mode:Managed Channel=0 Access Point: Not-Associated Bit Rate:0 kb/s Tx-Power:16 dBm Retry short limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:off Link Quality:0 Signal level:0 Noise level:0 Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0

    Read the article

  • iPhone: CPU power to do DSP/Fourier transform/frequency domain?

    - by mahboudz
    I want to analyze MIC audio on an ongoing basis (not just a snipper or prerecorded sample), and display frequency graph and filter out certain aspects of the audio. Is the iPhone powerful enough for that? I suspect the answer is a yes, given the Google and iPhone voice recognition, Shazaam and other music recognition apps, and guitar tuner apps out there. However, I don't know what limitations I'll have to deal with. Anyone play around with this area?

    Read the article

  • How to handle choice field with JPA 2, Hibernate 3.5

    - by phmr
    I have an entity with Integer attributes that looks like this in proto code: class MyEntity: String name Integer frequency Integer type def getFrequency() def getType() get* accessors return strings according to this table. value(type) HumanReadableString(type) 1 BSD 2 Apache 3 GPL min frequency max frequency HumanReadableString(frequency) 0 1000 rare 1000 2000 frequent 2001 3000 sexy It should be possible to get all possible values that an attribute can take, example: getChoices(MyEntity, "type") returns ("rare", "frequent", "sexy") It should be possible to get the bound value from the string: getValue(MyEntity, "frequency", "sexy") returns (2000,3000)

    Read the article

  • Simple way to play a single frequency in java?

    - by alleywayjack
    I just want to play a very simple, straight forward note by giving my computer a certain frequency as an integer, and from there I can figure out how to make it play the note longer or shorter. It does not necessarily have to come out of the actual sound card - if it's generated and output by the internal speaker that's okay. I looked at the midi libraries that java has included, and they are way more than what I want to do. This just needs to be very basic.

    Read the article

  • Converting from samplerate/cutoff frequency to pi-radians/sample in a discrete time sampled IIR filter system.

    - by Fake Name
    I am working on doing some digital filter work using Python and Numpy/Scipy. I'm using scipy.signal.iirdesign to generate my filter coefficents, but it requires the filter passband coefficents in a format I am not familiar with wp, ws : float Passband and stopband edge frequencies, normalized from 0 to 1 (1 corresponds to pi radians / sample). For example: Lowpass: wp = 0.2, ws = 0.3 Highpass: wp = 0.3, ws = 0.2 (from here) I'm not familiar with digital filters (I'm coming from a hardware design background). In an analog context, I would determine the desired slope and the 3db down point, and calculate component values from that. In this context, how do I take a known sample rate, a desired corner frequency, and a desired rolloff, and calculate the wp, ws values from that? (This might be more appropriate for math.stackexchange. I'm not sure)

    Read the article

  • how to get audio frequency data from a wave file?

    - by potlee
    I want to build a speech recognition engine in ruby. I know i'll never get there, doing it just for fun. I need to get data for the frequencies of the sound stored in a wav file to compare with data i already have of different sounds that i want to recognize. I will write the code in ruby but i dont think there are any libraries for this written in ruby, they would be too slow if there were any anyway. The good thing about ruby is I'll be able to use libraries for .net via IronRuby or Java via Jruby. How can i get the frequency data?

    Read the article

  • Why does cpuinfo report that my frequency is slower?

    - by Avery Chan
    My machine is running off of a AMD Sempron(tm) X2 190 Processor. According the marketing copy, it should be running at around 2.5 Ghz. Why is the cpu speed being reported as something lower? Spec description (in Chinese) $ cat /proc/cpuinfo processor : 0 vendor_id : AuthenticAMD cpu family : 16 model : 6 model name : AMD Sempron(tm) X2 190 Processor stepping : 3 microcode : 0x10000c8 cpu MHz : 800.000 cache size : 512 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl nonstop_tsc extd_apicid pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt npt lbrv svm_lock nrip_save bogomips : 5022.89 TLB size : 1024 4K pages clflush size : 64 cache_alignment : 64 address sizes : 48 bits physical, 48 bits virtual power management: ts ttp tm stc 100mhzsteps hwpstate processor : 1 vendor_id : AuthenticAMD cpu family : 16 model : 6 model name : AMD Sempron(tm) X2 190 Processor stepping : 3 microcode : 0x10000c8 cpu MHz : 800.000 cache size : 512 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 apicid : 1 initial apicid : 1 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl nonstop_tsc extd_apicid pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt npt lbrv svm_lock nrip_save bogomips : 5022.82 TLB size : 1024 4K pages clflush size : 64 cache_alignment : 64 address sizes : 48 bits physical, 48 bits virtual power management: ts ttp tm stc 100mhzsteps hwpstate

    Read the article

  • High Jitter in NTP and poll value never goes above 128

    - by Aseem
    I have a lot of servers syncing to the same NTP servers (4). Not every server is in the same LAN. Some are 3 hops away from the NTP servers and some are 6 hops away. On couple of servers I see that the poll value never touches the 1024 mark and the jitter value is in double digits. Could it be due to the system hardware? These are windows servers (physical) and require as accurate time as possible. Please advice what I should do. Some of the stats that I collected manually from the bad box (which is 6 hops away from the ntp servers) C:\Program Files (x86)\NTP>ntpq -p -n remote refid st t when poll reach delay offset jitter ============================================================================== +*.*.*.25 *.*.*.233 2 u 12 128 377 1.210 -12.579 14.913 +*.*.*.26 *.*.*.233 2 u 96 128 377 1.067 -2.235 9.885 **.*.*.27 *.*.*.233 2 u 24 128 377 1.038 -7.569 11.178 +*.*.*.28 *.*.*.233 2 u 49 128 377 1.288 -11.058 14.544 remote refid st t when poll reach delay offset jitter ============================================================================== +*.*.*.25 *.*.*.233 2 u 124 128 377 0.614 -6.212 5.329 +*.*.*.26 *.*.*.233 2 u 93 128 377 0.910 -9.431 3.111 +*.*.*.27 *.*.*.233 2 u 1 128 377 0.824 -7.428 3.129 **.*.*.28 *.*.*.233 2 u 84 128 377 1.503 -8.230 3.511 remote refid st t when poll reach delay offset jitter ============================================================================== **.*.*.25 *.*.*.233 2 u 117 128 377 1.235 -4.084 11.405 +*.*.*.26 *.*.*.233 2 u 96 128 377 1.335 -11.813 13.130 +*.*.*.27 *.*.*.233 2 u 130 128 377 1.549 -14.036 16.381 -*.*.*.28 *.*.*.233 2 u 79 128 377 1.258 13.395 22.203 remote refid st t when poll reach delay offset jitter ============================================================================== **.*.*.25 *.*.*.233 2 u 88 128 377 1.235 -4.084 14.068 +*.*.*.26 *.*.*.233 2 u 63 128 377 1.335 -11.813 17.086 +*.*.*.27 *.*.*.233 2 u 103 128 377 1.549 -14.036 20.691 -*.*.*.28 *.*.*.233 2 u 47 128 377 1.258 13.395 20.231 remote refid st t when poll reach delay offset jitter ============================================================================== +*.*.*.25 *.*.*.233 2 u 47 64 377 0.652 -15.805 14.077 **.*.*.26 *.*.*.233 2 u 11 64 377 1.013 -14.423 11.375 -*.*.*.27 *.*.*.233 2 u 63 64 377 0.765 -2.030 7.680 +*.*.*.28 *.*.*.233 2 u 4 64 377 1.191 -17.980 14.393 remote refid st t when poll reach delay offset jitter ============================================================================== -*.*.*.25 *.*.*.233 2 u 3 128 377 1.576 18.665 21.999 +*.*.*.26 *.*.*.233 2 u 73 128 377 0.637 -5.012 14.405 **.*.*.27 *.*.*.233 2 u 127 128 377 0.272 -8.237 14.438 +*.*.*.28 *.*.*.233 2 u 123 128 377 1.190 -14.383 18.875 C:\Program Files (x86)\NTP>ntpdc -c loopinfo offset: -0.016430 s frequency: 7.106 ppm poll adjust: 18 watchdog timer: 133 s offset: -0.016430 s frequency: 7.106 ppm poll adjust: 18 watchdog timer: 341 s offset: -0.000149 s frequency: 6.645 ppm poll adjust: 0 watchdog timer: 383 s offset: 0.015735 s frequency: 6.725 ppm poll adjust: 7 watchdog timer: 577 s offset: -0.010331 s frequency: 6.748 ppm poll adjust: 21 watchdog timer: 567 s offset: -0.009427 s frequency: 6.687 ppm poll adjust: 28 watchdog timer: 301 s offset: -0.007361 s frequency: 6.612 ppm poll adjust: 30 watchdog timer: 155 s offset: -0.008106 s frequency: 4.358 ppm poll adjust: 30 watchdog timer: 291 s NTP.conf # NTP configuration file # Use drift file driftfile "C:\Program Files (x86)\NTP\ntp.drift" # Logs statistics loopstats peerstats clockstats statsdir "C:\Program Files (x86)\NTP\logs\" # directory for statistics files filegen peerstats file peerstats type day enable filegen loopstats file loopstats type day enable filegen clockstats file clockstats type day enable logfile "C:\Program Files (x86)\NTP\logs\syslog.txt" # Use specific NTP servers server *.*.*.25 minpoll 4 maxpoll 7 iburst server *.*.*.26 minpoll 4 maxpoll 7 iburst server *.*.*.27 minpoll 4 maxpoll 7 iburst server *.*.*.28 minpoll 4 maxpoll 7 iburst

    Read the article

  • How to monitor changes in the frequency of network latency spikes over time?

    - by dequis
    I'm currently trying to troubleshoot an issue with my network in which I get latency spikes up to 200 seconds (normally around 50 secs) in an apparently random way at apparently random moments of the day. While trying to find what part of my messy network needs to be blamed (outside of the scope of this question - discussed a bit on chat), I realized I have no reliable way to confirm that a change actually improved anything. So far, the main way in which i notice this is that irssi shows [Lag: 15 (??)] in the statusbar, increasing every 5 seconds, and all other connections seem to be affected too. Since this depends on my observations, it's not a very reliable method to know how often it really happens. Note that just sending ICMP pings is probably not enough, but that's just my guess. It might be a "bufferbloat" issue, it might be packet loss, it might only apply to persistent connections. I suspect this because a few months ago, when the issue started, I had a "ping" command running in background and it didn't show anything weird at all during the latency spikes. This seems to have changed now (pings don't go through), but still, I'd prefer something more robust.

    Read the article

  • How to monitor IO svctm with every 5 mins frequency using nagios?

    - by sabya
    I want to collect samples of iostat's svctm, await every 5 mins from all of my servers and store them in nagios. I want to get the values for what is happening in every 5 minutes (not since boot time, iostat's first output gives values since boot time). How can I do it in nagios? EDIT The tps should NOT be calculated #of transactions happened since reboot divided by uptime. What I want is # of transferred happened in last X mins divided X*60.

    Read the article

  • Wireless Connected But No Internet Connection (Ubuntu 12.04)

    - by Zxy
    I am using same network for 2 days and everything was normal. However, today even though it shows me as connected to the network, I do not have internet connection. If I use ethernet cable instead of wireless, I am still able to connect to the internet. Also my friends are able to connect to the wireless network and they can get internet connection. I did not update or install anything since yesterday. Therefore I do not have any idea why it is happening. Here is some information about my connection: I will be appreciate to any kind of help. root@ghostrider:/etc/resolvconf# ping 127.0.0.1 PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. 64 bytes from 127.0.0.1: icmp_req=1 ttl=64 time=0.042 ms 64 bytes from 127.0.0.1: icmp_req=2 ttl=64 time=0.023 ms 64 bytes from 127.0.0.1: icmp_req=3 ttl=64 time=0.036 ms 64 bytes from 127.0.0.1: icmp_req=4 ttl=64 time=0.040 ms ^C --- 127.0.0.1 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 2998ms rtt min/avg/max/mdev = 0.023/0.035/0.042/0.008 ms root@ghostrider:/etc/resolvconf# ping 192.168.1.3 PING 192.168.1.3 (192.168.1.3) 56(84) bytes of data. ^C --- 192.168.1.3 ping statistics --- 19 packets transmitted, 0 received, 100% packet loss, time 18143ms root@ghostrider:/etc/resolvconf# ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. ^C --- 8.8.8.8 ping statistics --- 11 packets transmitted, 0 received, 100% packet loss, time 10079ms root@ghostrider:/etc/resolvconf# cat /etc/lsb-release; uname -a DISTRIB_ID=Ubuntu DISTRIB_RELEASE=12.04 DISTRIB_CODENAME=precise DISTRIB_DESCRIPTION="Ubuntu 12.04 LTS" Linux ghostrider 3.2.0-24-generic-pae #39-Ubuntu SMP Mon May 21 18:54:21 UTC 2012 i686 i686 i386 GNU/Linux root@ghostrider:/etc/resolvconf# lspci -nnk | grep -iA2 net 03:00.0 Ethernet controller [0200]: Atheros Communications Inc. AR8131 Gigabit Ethernet [1969:1063] (rev c0) Subsystem: Lenovo Device [17aa:3956] Kernel driver in use: atl1c -- 04:00.0 Network controller [0280]: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller [14e4:4727] (rev 01) Subsystem: Broadcom Corporation Device [14e4:0510] Kernel driver in use: wl root@ghostrider:/etc/resolvconf# lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 007: ID 0489:e00d Foxconn / Hon Hai Bus 001 Device 004: ID 1c7a:0801 LighTuning Technology Inc. Fingerprint Reader Bus 001 Device 005: ID 064e:f219 Suyin Corp. Bus 002 Device 010: ID 0424:2412 Standard Microsystems Corp. Bus 002 Device 004: ID 046d:c52b Logitech, Inc. Unifying Receiver Bus 002 Device 011: ID 0403:6010 Future Technology Devices International, Ltd FT2232C Dual USB-UART/FIFO IC root@ghostrider:/etc/resolvconf# iwconfig lo no wireless extensions. eth1 IEEE 802.11 ESSID:"PoliTekno" Mode:Managed Frequency:2.462 GHz Access Point: 00:16:E3:40:C3:E4 Bit Rate=54 Mb/s Tx-Power:24 dBm Retry min limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=5/5 Signal level=-52 dBm Noise level=-97 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0 eth0 no wireless extensions. root@ghostrider:/etc/resolvconf# rfkill list all 0: brcmwl-0: Wireless LAN Soft blocked: no Hard blocked: no 1: ideapad_wlan: Wireless LAN Soft blocked: no Hard blocked: no 2: ideapad_bluetooth: Bluetooth Soft blocked: no Hard blocked: no 5: hci0: Bluetooth Soft blocked: no Hard blocked: no root@ghostrider:/etc/resolvconf# lsmod Module Size Used by nls_iso8859_1 12617 0 nls_cp437 12751 0 vfat 17308 0 fat 55605 1 vfat usb_storage 39646 0 uas 17828 0 snd_hda_codec_realtek 174055 1 rfcomm 38139 12 parport_pc 32114 0 ppdev 12849 0 bnep 17830 2 joydev 17393 0 ftdi_sio 35859 1 usbserial 37173 3 ftdi_sio snd_hda_intel 32765 3 snd_hda_codec 109562 2 snd_hda_codec_realtek,snd_hda_intel snd_hwdep 13276 1 snd_hda_codec acer_wmi 23612 0 hid_logitech_dj 18177 0 snd_pcm 80845 2 snd_hda_intel,snd_hda_codec uvcvideo 67203 0 btusb 17912 2 snd_seq_midi 13132 0 videodev 86588 1 uvcvideo bluetooth 158438 23 rfcomm,bnep,btusb psmouse 72919 0 usbhid 41906 1 hid_logitech_dj snd_rawmidi 25424 1 snd_seq_midi intel_ips 17753 0 serio_raw 13027 0 root@ghostrider:/etc/resolvconf# ping 127.0.0.1 PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data. 64 bytes from 127.0.0.1: icmp_req=1 ttl=64 time=0.042 ms 64 bytes from 127.0.0.1: icmp_req=2 ttl=64 time=0.023 ms 64 bytes from 127.0.0.1: icmp_req=3 ttl=64 time=0.036 ms 64 bytes from 127.0.0.1: icmp_req=4 ttl=64 time=0.040 ms ^C --- 127.0.0.1 ping statistics --- 4 packets transmitted, 4 received, 0% packet loss, time 2998ms rtt min/avg/max/mdev = 0.023/0.035/0.042/0.008 ms root@ghostrider:/etc/resolvconf# ping 192.168.1.3 PING 192.168.1.3 (192.168.1.3) 56(84) bytes of data. ^C --- 192.168.1.3 ping statistics --- 19 packets transmitted, 0 received, 100% packet loss, time 18143ms root@ghostrider:/etc/resolvconf# ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. ^C --- 8.8.8.8 ping statistics --- 11 packets transmitted, 0 received, 100% packet loss, time 10079ms root@ghostrider:/etc/resolvconf# cat /etc/lsb-release; uname -a DISTRIB_ID=Ubuntu DISTRIB_RELEASE=12.04 DISTRIB_CODENAME=precise DISTRIB_DESCRIPTION="Ubuntu 12.04 LTS" Linux ghostrider 3.2.0-24-generic-pae #39-Ubuntu SMP Mon May 21 18:54:21 UTC 2012 i686 i686 i386 GNU/Linux root@ghostrider:/etc/resolvconf# lspci -nnk | grep -iA2 net 03:00.0 Ethernet controller [0200]: Atheros Communications Inc. AR8131 Gigabit Ethernet [1969:1063] (rev c0) Subsystem: Lenovo Device [17aa:3956] Kernel driver in use: atl1c -- 04:00.0 Network controller [0280]: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller [14e4:4727] (rev 01) Subsystem: Broadcom Corporation Device [14e4:0510] Kernel driver in use: wl root@ghostrider:/etc/resolvconf# lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 007: ID 0489:e00d Foxconn / Hon Hai Bus 001 Device 004: ID 1c7a:0801 LighTuning Technology Inc. Fingerprint Reader Bus 001 Device 005: ID 064e:f219 Suyin Corp. Bus 002 Device 010: ID 0424:2412 Standard Microsystems Corp. Bus 002 Device 004: ID 046d:c52b Logitech, Inc. Unifying Receiver Bus 002 Device 011: ID 0403:6010 Future Technology Devices International, Ltd FT2232C Dual USB-UART/FIFO IC root@ghostrider:/etc/resolvconf# iwconfig lo no wireless extensions. eth1 IEEE 802.11 ESSID:"PoliTekno" Mode:Managed Frequency:2.462 GHz Access Point: 00:16:E3:40:C3:E4 Bit Rate=54 Mb/s Tx-Power:24 dBm Retry min limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=5/5 Signal level=-52 dBm Noise level=-97 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0 eth0 no wireless extensions. root@ghostrider:/etc/resolvconf# rfkill list all 0: brcmwl-0: Wireless LAN Soft blocked: no Hard blocked: no 1: ideapad_wlan: Wireless LAN Soft blocked: no Hard blocked: no 2: ideapad_bluetooth: Bluetooth Soft blocked: no Hard blocked: no 5: hci0: Bluetooth Soft blocked: no Hard blocked: no root@ghostrider:/etc/resolvconf# lsmod Module Size Used by nls_iso8859_1 12617 0 nls_cp437 12751 0 vfat 17308 0 fat 55605 1 vfat usb_storage 39646 0 uas 17828 0 snd_hda_codec_realtek 174055 1 rfcomm 38139 12 parport_pc 32114 0 ppdev 12849 0 bnep 17830 2 joydev 17393 0 ftdi_sio 35859 1 usbserial 37173 3 ftdi_sio snd_hda_intel 32765 3 snd_hda_codec 109562 2 snd_hda_codec_realtek,snd_hda_intel snd_hwdep 13276 1 snd_hda_codec acer_wmi 23612 0 hid_logitech_dj 18177 0 snd_pcm 80845 2 snd_hda_intel,snd_hda_codec uvcvideo 67203 0 btusb 17912 2 snd_seq_midi 13132 0 videodev 86588 1 uvcvideo bluetooth 158438 23 rfcomm,bnep,btusb psmouse 72919 0 usbhid 41906 1 hid_logitech_dj snd_rawmidi 25424 1 snd_seq_midi intel_ips 17753 0 serio_raw 13027 0 hid 77367 2 hid_logitech_dj,usbhid ideapad_laptop 17890 0 sparse_keymap 13658 2 acer_wmi,ideapad_laptop lib80211_crypt_tkip 17275 0 snd_seq_midi_event 14475 1 snd_seq_midi snd_seq 51567 2 snd_seq_midi,snd_seq_midi_event wl 2646601 0 wmi 18744 1 acer_wmi i915 414672 3 drm_kms_helper 45466 1 i915 snd_timer 28931 2 snd_pcm,snd_seq mac_hid 13077 0 snd_seq_device 14172 3 snd_seq_midi,snd_rawmidi,snd_seq lib80211 14040 2 lib80211_crypt_tkip,wl drm 197692 4 i915,drm_kms_helper i2c_algo_bit 13199 1 i915 snd 62064 15 snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_se q,snd_timer,snd_seq_device video 19068 1 i915 mei 36570 0 soundcore 14635 1 snd snd_page_alloc 14108 2 snd_hda_intel,snd_pcm lp 17455 0 parport 40930 3 parport_pc,ppdev,lp atl1c 36718 0 root@ghostrider:/etc/resolvconf# nm-tool NetworkManager Tool State: connected (global) - Device: eth1 [PoliTekno] ---------------------------------------------------- Type: 802.11 WiFi Driver: wl State: connected Default: yes HW Address: AC:81:12:7F:6B:B2 Capabilities: Speed: 54 Mb/s Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points (* = current AP) CnDStudios: Infra, 00:12:BF:3F:0A:8A, Freq 2412 MHz, Rate 54 Mb/s, Strength 85 WPA AIR_TIES: Infra, 00:1C:A8:6E:84:32, Freq 2462 MHz, Rate 54 Mb/s, Strength 72 WPA2 VKSS: Infra, 00:E0:4D:01:0D:47, Freq 2452 MHz, Rate 54 Mb/s, Strength 62 WPA2 PROGEDA: Infra, 00:1A:2A:60:BF:61, Freq 2462 MHz, Rate 54 Mb/s, Strength 47 WPA MobilAtolye: Infra, 72:2B:C1:65:75:3C, Freq 2422 MHz, Rate 54 Mb/s, Strength 35 WPA WPA2 AIRTIES_WAR-141: Infra, 00:1C:A8:AB:AA:48, Freq 2422 MHz, Rate 54 Mb/s, Strength 35 WPA WPA2 tilda_biri_yeni: Infra, 54:E6:FC:B0:3C:E9, Freq 2437 MHz, Rate 0 Mb/s, Strength 34 WEP *PoliTekno: Infra, 00:16:E3:40:C3:E4, Freq 2462 MHz, Rate 54 Mb/s, Strength 100 WPA2 AIRTIES_RJY: Infra, 00:1A:2A:BD:85:16, Freq 2462 MHz, Rate 54 Mb/s, Strength 55 WEP IPv4 Settings: Address: 0.0.0.0 Prefix: 24 (255.255.255.0) Gateway: 192.168.1.1 DNS: 192.168.1.1 - Device: eth0 ----------------------------------------------------------------- Type: Wired Driver: atl1c State: unavailable Default: no HW Address: F0:DE:F1:6C:90:65 Capabilities: Carrier Detect: yes Speed: 100 Mb/s Wired Properties Carrier: off root@ghostrider:/etc/resolvconf# sudo iwlist scan lo Interface doesn't support scanning. eth1 Scan completed : Cell 01 - Address: 00:16:E3:40:C3:E4 ESSID:"PoliTekno" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:5/5 Signal level:-48 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 02 - Address: 00:E0:4D:01:0D:47 ESSID:"VKSS" Mode:Managed Frequency:2.452 GHz (Channel 9) Quality:4/5 Signal level:-64 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s 48 Mb/s; 54 Mb/s Cell 03 - Address: 00:1C:A8:AB:AA:48 ESSID:"AIRTIES_WAR-141" Mode:Managed Frequency:2.422 GHz (Channel 3) Quality:2/5 Signal level:-77 dBm Noise level:-95 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: Unknown: DDB20050F204104A0001101049001E007FC5100018DE7CF0D8B70223A62711C18926AC290E30303030303139631044000102103B0001031047001076B31BC241E953CB99C3872554425A28102100194169725469657320576972656C657373204E6574776F726B73102300074169723534343010240008312E322E302E31321042000F4154303939313131383030323832351054000800060050F20400011011000741697235343430100800020084103C000103 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 04 - Address: 72:2B:C1:65:75:3C ESSID:"MobilAtolye" Mode:Managed Frequency:2.422 GHz (Channel 3) Quality:2/5 Signal level:-78 dBm Noise level:-92 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : TKIP CCMP Authentication Suites (1) : PSK IE: Unknown: DDA20050F204104A0001101044000102103B00010310470010BC329E001DD811B28601722BC165753C1021001D48756177656920546563686E6F6C6F6769657320436F2E2C204C74642E1023001C48756177656920576972656C6573732041636365737320506F696E74102400065254323836301042000831323334353637381054000800060050F204000110110009487561776569415053100800020084103C000100 IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : TKIP CCMP Authentication Suites (1) : PSK Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 9 Mb/s 18 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 12 Mb/s 24 Mb/s; 48 Mb/s Cell 05 - Address: 00:12:BF:3F:0A:8A ESSID:"CnDStudios" Mode:Managed Frequency:2.412 GHz (Channel 1) Quality:5/5 Signal level:-47 dBm Noise level:-95 dBm IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 22 Mb/s 6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s 36 Mb/s; 48 Mb/s; 54 Mb/s Cell 06 - Address: 00:1C:A8:6E:84:32 ESSID:"AIR_TIES" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:5/5 Signal level:-56 dBm Noise level:-98 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : CCMP Pairwise Ciphers (1) : CCMP Authentication Suites (1) : PSK Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 22 Mb/s 6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s 36 Mb/s; 48 Mb/s; 54 Mb/s Cell 07 - Address: 54:E6:FC:B0:3C:E9 ESSID:"tilda_biri_yeni" Mode:Managed Frequency:2.437 GHz (Channel 6) Quality:1/5 Signal level:-85 dBm Noise level:-99 dBm Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 12 Mb/s; 24 Mb/s; 36 Mb/s; 9 Mb/s; 18 Mb/s 48 Mb/s; 54 Mb/s Cell 08 - Address: 18:28:61:16:57:C3 ESSID:"obilet" Mode:Managed Frequency:2.437 GHz (Channel 6) Quality:1/5 Signal level:-88 dBm Noise level:-99 dBm IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s 24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s 12 Mb/s; 48 Mb/s Cell 09 - Address: 00:1A:2A:60:BF:61 ESSID:"PROGEDA" Mode:Managed Frequency:2.462 GHz (Channel 11) Quality:2/5 Signal level:-75 dBm Noise level:-98 dBm IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (1) : TKIP Authentication Suites (1) : PSK Encryption key:on Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 22 Mb/s 6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s 36 Mb/s; 48 Mb/s; 54 Mb/s eth0 Interface doesn't support scanning.

    Read the article

  • cpufreq-selector, cpufreq-info reporting wrong max speed

    - by dty
    Hi, I've just built a new machine with a Core i5-760 CPU. Max speed is 2.80GHz (turbo mode notwithstanding). I've also done a vanilla install of Ubuntu 10.10. I've added the cpufreq-selector applet to the top panel, and its menus only allow me to select up to 2.39GHz. If I select the "performance" governor, it also shows 2.39GHz. cpufreq-info reports: $ cpufreq-info cpufrequtils 007: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to [email protected], please. analyzing CPU 0: driver: acpi-cpufreq CPUs which run at the same hardware frequency: 0 1 2 3 CPUs which need to have their frequency coordinated by software: 0 maximum transition latency: 10.0 us. hardware limits: 1.20 GHz - 2.39 GHz available frequency steps: 2.39 GHz, 2.26 GHz, 2.13 GHz, 2.00 GHz, 1.86 GHz, 1.73 GHz, 1.60 GHz, 1.46 GHz, 1.33 GHz, 1.20 GHz available cpufreq governors: conservative, ondemand, userspace, powersave, performance current policy: frequency should be within 1.20 GHz and 2.39 GHz. The governor "ondemand" may decide which speed to use within this range. current CPU frequency is 1.20 GHz. cpufreq stats: 2.39 GHz:13.74%, 2.26 GHz:0.09%, 2.13 GHz:0.08%, 2.00 GHz:0.08%, 1.86 GHz:0.07%, 1.73 GHz:0.07%, 1.60 GHz:0.08%, 1.46 GHz:0.08%, 1.33 GHz:0.11%, 1.20 GHz:85.61% (15560) [...CPUs 1-3 elided, but similar...] Any idea how to get Ubuntu and the various tools to recognise this as a 2.80GHz processor? And ideally to report the actual speed when running in turbo mode too, but that's not critical. Edit: I should probably add that the BIOS (& Windows) are quite happy that it's a 2.80GHz CPU. Thanks.

    Read the article

  • How to discriminate from two nodes with identical frequencies in a Huffman's tree?

    - by Omega
    Still on my quest to compress/decompress files with a Java implementation of Huffman's coding (http://en.wikipedia.org/wiki/Huffman_coding) for a school assignment. From the Wikipedia page, I quote: Create a leaf node for each symbol and add it to the priority queue. While there is more than one node in the queue: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. Add the new node to the queue. The remaining node is the root node and the tree is complete. Now, emphasis: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. So I have to take two nodes with the lowest frequency. What if there are multiple nodes with the same low frequency? How do I discriminate which one to use? The reason I ask this is because Wikipedia has this image: And I wanted to see if my Huffman's tree was the same. I created a file with the following content: aaaaeeee nnttmmiihhssfffouxprl And this was the result: Doesn't look so bad. But there clearly are some differences when multiple nodes have the same frequency. My questions are the following: What is Wikipedia's image doing to discriminate the nodes with the same frequency? Is my tree wrong? (Is Wikipedia's image method the one and only answer?) I guess there is one specific and strict way to do this, because for our school assignment, files that have been compressed by my program should be able to be decompressed by other classmate's programs - so there must be a "standard" or "unique" way to do it. But I'm a bit lost with that. My code is rather straightforward. It literally just follows Wikipedia's listed steps. The way my code extracts the two nodes with the lowest frequency from the queue is to iterate all nodes and if the current node has a lower frequency than any of the two "smallest" known nodes so far, then it replaces the highest one. Just like that.

    Read the article

  • Problems re-populating select options in Rails when form returned with errors

    - by Rick
    I have a form with 2 select options in it -- frequency and duration. When there are errors with the form, and it is returned to the browser, the select options are not re-populated with the selections the user made even though the returned values for those fields match the values of options in the selects. Also, when the form is returned, these fields are not marked as having errors even though their values are blank. Here's the frequency and duration fields in Rails <%= frequency_select c, :frequency %> <%= duration_select c, :duration %> The method for frequency_select is def frequency_select(f, method) options = [["day", 1.day], ["other day", 2.days], ["week", 1.week]] f.select method, options, :include_blank => true end And the method for duration_select is def duration_select(f, method, unit="day" ) values, units = *case unit when "day" : [[[5, 5], [15, 15], [30, 29]], "days"] when "other day" : [[[15, 15], [30, 29], [45,45]], "days"] when "week" : [[[4, 29], [6, 43], [8, 57]], "weeks"] end f.select method, values.map {|(label, i)| ["#{label} #{units}", i.days]}, :include_blank => true end If you enter a value into one or both of these fields and submit the form without completing part of it (any part of it), the form is returned to the user (as would be expected), but the duration and frequency fields are not re-populated with the user's selection. If I add this bit of code to the form <p><%= @challenge.attributes.inspect %></p> I see that this for duration and frequency when the form is returned to the browser: "duration"=>3888000, "frequency"=>172800 These values match values on the options in the select fields. Is there anything special in Rails that needs to be done so that the select fields are re-populated with the user's selections? Any thoughts on what the problem could be or what I should try next? Help is greatly appreciated! -Rick PS If you look at some of the other questions, you'll notice I've asked about this in the past. At one point, I thought the form was returning values for frequency and duration in days rather than seconds, but that's not the case. PPS Here's one other bit of information that might matter, but my tests indicate that it probably does not. (Though, I'm a bit of a newbie to this, so don't take my word for it.) These two fields are chained together using the cascade jquery plugin. The javascript is included on the page (not in a separate file) and some of the js is being created by Rails. First, here are the scripts as they appear in the browser. The first is the script to generate the options for the duration select and the second is the script required by the Cascade plugin to trigger the field chaining. <script type="text/javascript"> var list1 = [ {'When':'86400','Value':' ','Text':' '}, {'When':'172800','Value':' ','Text':' '}, {'When':'604800','Value':' ','Text':' '}, {'When':'86400','Value':'432000','Text':'5 days'}, {'When':'86400','Value':'1296000','Text':'15 days'}, {'When':'86400','Value':'2505600','Text':'30 days'}, {'When':'172800','Value':'1296000','Text':'15 days'}, {'When':'172800','Value':'2505600','Text':'30 days'}, {'When':'172800','Value':'3888000','Text':'45 days'}, {'When':'604800','Value':'2505600','Text':'4 weeks'}, {'When':'604800','Value':'3715200','Text':'6 weeks'}, {'When':'604800','Value':'4924800','Text':'8 weeks'} ]; function commonTemplate(item) { return "<option value='" + item.Value + "'>" + item.Text + "</option>"; }; function commonMatch(selectedValue) { return this.When == selectedValue; }; </script> <script type="text/javascript"> jQuery(document).ready(function(){ jQuery("#challenge_duration, #user_challenge_duration").cascade("#challenge_frequency, #user_challenge_frequency",{ list: list1, template: commonTemplate, match: commonMatch }) }); </script> And here's a bit of the the first script as it is in the erb file -- you see that some of the script is being generated by Rails <%= [ [1.day, [[5, 5], [15,15], [30, 29]], "days"], [2.days, [[15, 15], [30, 29], [45, 45]], "days"], [1.week, [[4, 29], [6, 43], [8, 57]], "weeks"]].map do |(frequency, durations, unit)| durations.map do |(label, value)| "{'When':'#{frequency}','Value':'#{value.days}','Text':'#{label} #{unit}'}" end end.join(",\n") -%> Now, the reason I don't think that it matters whether the duration is being generated with JS is the problem still exists if I remove all the JS the problem also affects the frequency field, whose options are not being generated by the JS

    Read the article

  • Avoiding seasonality assumption for stl() or decompose() in R

    - by user303922
    Hello everybody, I have high frequency commodity price data that I need to analyze. My objective is to not assume any seasonal component and just identify a trend. Here is where I run into problems with R. There are two main functions that I know of to analyze this time series: decompose() and stl(). The problem is that they both take a ts object type with a frequency parameter greater than or equal to 2. Is there some way I can assume a frequency of 1 per unit time and still analyze this time series using R? I'm afraid that if I assume frequency greater than 1 per unit time, and seasonality is calculated using the frequency parameter, then my forecasts are going to depend on that assumption. names(crude.data)=c('Date','Time','Price') names(crude.data) freq = 2 win.graph() plot(crude.data$Time,crude.data$Price, type="l") crude.data$Price = ts(crude.data$Price,frequency=freq) I want frequency to be 1 per unit time but then decompose() and stl() don't work! dim(crude.data$Price) decom = decompose(crude.data$Price) win.graph() plot(decom$random[2:200],type="line") acf(decom$random[freq:length(decom$random-freq)]) Thank you.

    Read the article

  • C# Freq. Table with Random Values

    - by Sef
    Hello, I am trying to write a frequency program that will represent a bar diagram (in console code). The problem is i have no idea how exactly to caculate this frequency or how do i exactly then give the bars different heights according to there frequency (trough calculation). The frequency height is capped at 21. (meaning the bars go from 1 to 21, so the max bar height would be for example 21 stars(* as display sign for the bar itself). A calculation i have so far (although not sure if correct) for frequency: This array takes the random values generated: for (int j = 0; j < T.Length; j++) { T[j] = (MaxHeight* T[j]) / Ber.GreatestElement(T); Console.Write("{0,7}", T[j]); } This results in values between 0 and 21 -- Based on the values my bars should give a certain height compared to all the other frequency values. (for example 8000 could have 21 in height where 39 could have 1). To represent this diagram i used 2 for loops to display height and width (keep in mind i only wish to use Using System; to keep it to the "basics"). for (int height= 1; height<= 21; height++) { for (int width= 0; width<= 10; width++) { if(...??) { Console.Write("{0,7}", bar); // string bar= ("*"); } else { Console.Write("{0,7}", empty); } } Console.WriteLine(); } So so far i have a entire field filled with * and the random values generated along with their frequency value (although i have no idea if the freq value is properly calculated). I assume i need a if (.....) in the second for but i cannot seem to get further then this. Thanks in advance!

    Read the article

  • What are the frequencies of current in computers' external peripheral cables and internal buses?

    - by Tim
    From Wikipedia, three different cases of current frequency are discussed along with the types of cables that are suitable for them: An Extra Ordinary electrical cables suffice to carry low frequency AC, such as mains power, which reverses direction 100 to 120 times per second (cycling 50 to 60 times per second). However, they cannot be used to carry currents in the radio frequency range or higher, which reverse direction millions to billions of times per second, because the energy tends to radiate off the cable as radio waves, causing power losses. Radio frequency currents also tend to reflect from discontinuities in the cable such as connectors, and travel back down the cable toward the source. These reflections act as bottlenecks, preventing the power from reaching the destination. Transmission lines use specialized construction such as precise conductor dimensions and spacing, and impedance matching, to carry electromagnetic signals with minimal reflections and power losses. Types of transmission line include ladder line, coaxial cable, dielectric slabs, stripline, optical fiber, and waveguides. The higher the frequency, the shorter are the waves in a transmission medium. Transmission lines must be used when the frequency is high enough that the wavelength of the waves begins to approach the length of the cable used. To conduct energy at frequencies above the radio range, such as millimeter waves, infrared, and light, the waves become much smaller than the dimensions of the structures used to guide them, so transmission line techniques become inadequate and the methods of optics are used. I wonder what the frequencies are for the currents in computers' external peripheral cables, such as Ethernet cable, USB cable, and in computers' internal buses? Are the cables also made specially for the frequencies? Thanks!

    Read the article

  • unable to sniff traffic despite network interface being in monitor or promiscuous mode

    - by user65126
    I'm trying to sniff out my network's wireless traffic but am having issues. I'm able to put the card in monitor mode, but am unable to see any traffic except broadcasts, multicasts and probe/beacon frames. I have two network interfaces on this laptop. One is connected normally to 'linksys' and the other is in monitor mode. The interface in monitor mode is on the right channel. I'm not associated with the access point because, as I understand, I don't need to if using monitor mode (vs promiscuous). When I try to ping the router ip, I'm not seeing that traffic show up in wireshark. Here's my ifconfig settings: daniel@seasonBlack:~$ ifconfig eth0 Link encap:Ethernet HWaddr 00:1f:29:9e:b2:89 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:16 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:112 errors:0 dropped:0 overruns:0 frame:0 TX packets:112 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:8518 (8.5 KB) TX bytes:8518 (8.5 KB) wlan0 Link encap:Ethernet HWaddr 00:21:00:34:f7:f4 inet addr:192.168.1.116 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::221:ff:fe34:f7f4/64 Scope:Link UP BROADCAST RUNNING MTU:1500 Metric:1 RX packets:9758 errors:0 dropped:0 overruns:0 frame:0 TX packets:4869 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3291516 (3.2 MB) TX bytes:677386 (677.3 KB) wlan1 Link encap:UNSPEC HWaddr 00-02-72-7B-92-53-33-34-00-00-00-00-00-00-00-00 UP BROADCAST NOTRAILERS PROMISC ALLMULTI MTU:1500 Metric:1 RX packets:112754 errors:0 dropped:0 overruns:0 frame:0 TX packets:101 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:18569124 (18.5 MB) TX bytes:12874 (12.8 KB) wmaster0 Link encap:UNSPEC HWaddr 00-21-00-34-F7-F4-00-00-00-00-00-00-00-00-00-00 UP RUNNING MTU:0 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) wmaster1 Link encap:UNSPEC HWaddr 00-02-72-7B-92-53-00-00-00-00-00-00-00-00-00-00 UP RUNNING MTU:0 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Here's my iwconfig settings: daniel@seasonBlack:~$ iwconfig lo no wireless extensions. eth0 no wireless extensions. wmaster0 no wireless extensions. wlan0 IEEE 802.11bg ESSID:"linksys" Mode:Managed Frequency:2.437 GHz Access Point: 00:18:F8:D6:17:34 Bit Rate=54 Mb/s Tx-Power=27 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=68/70 Signal level=-42 dBm Noise level=-69 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0 wmaster1 no wireless extensions. wlan1 IEEE 802.11bg Mode:Monitor Frequency:2.437 GHz Tx-Power=27 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality:0 Signal level:0 Noise level:0 Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0 Here's how I know I'm on the right channel: daniel@seasonBlack:~$ iwlist channel lo no frequency information. eth0 no frequency information. wmaster0 no frequency information. wlan0 11 channels in total; available frequencies : Channel 01 : 2.412 GHz Channel 02 : 2.417 GHz Channel 03 : 2.422 GHz Channel 04 : 2.427 GHz Channel 05 : 2.432 GHz Channel 06 : 2.437 GHz Channel 07 : 2.442 GHz Channel 08 : 2.447 GHz Channel 09 : 2.452 GHz Channel 10 : 2.457 GHz Channel 11 : 2.462 GHz Current Frequency=2.437 GHz (Channel 6) wmaster1 no frequency information. wlan1 11 channels in total; available frequencies : Channel 01 : 2.412 GHz Channel 02 : 2.417 GHz Channel 03 : 2.422 GHz Channel 04 : 2.427 GHz Channel 05 : 2.432 GHz Channel 06 : 2.437 GHz Channel 07 : 2.442 GHz Channel 08 : 2.447 GHz Channel 09 : 2.452 GHz Channel 10 : 2.457 GHz Channel 11 : 2.462 GHz Current Frequency=2.437 GHz (Channel 6)

    Read the article

  • Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

    - by MarkPearl
    After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

    Read the article

  • How would i down-sample a .wav file then reconstruct it using nyquist? - in matlab [closed]

    - by martin
    Possible Duplicate: How would i down-sample a .wav file then reconstruct it using nyquist? - in matlab This is all done in MatLab 2010 My objective is to show the results of: undersampling, nyquist rate/ oversampling First i need to downsample the .wav file to get an incomplete/ or impartial data stream that i can then reconstuct. Heres the flow chart of what im going to be doing So the flow is analog signal - sampling analog filter - ADC - resample down - resample up - DAC - reconstruction analog filter what needs to be achieved: F= Frequency F(Hz=1/s) E.x. 100Hz = 1000 (Cyc/sec) F(s)= 1/(2f) Example problem: 1000 hz = Highest frequency 1/2(1000hz) = 1/2000 = 5x10(-3) sec/cyc or a sampling rate of 5ms This is my first signal processing project using matlab. what i have so far. % Fs = frequency sampled (44100hz or the sampling frequency of a cd) [test,fs]=wavread('test.wav'); % loads the .wav file left=test(:,1); % Plot of the .wav signal time vs. strength time=(1/44100)*length(left); t=linspace(0,time,length(left)); plot(t,left) xlabel('time (sec)'); ylabel('relative signal strength') **%this is were i would need to sample it at the different frequecys (both above and below and at) nyquist frequency.*I think.*** soundsc(left,fs) % shows the resaultant audio file , which is the same as original ( only at or above nyquist frequency however) Can anyone tell me how to make it better, and how to do the various sampling at different frequencies?

    Read the article

< Previous Page | 2 3 4 5 6 7 8 9 10 11 12 13  | Next Page >