On Mon, 05 May 2008 08:04:51 -0400, Randy Yates <yates@ieee.org> wrote:>dpierce.cartchunk.org@gmail.com writes: >> [...] >> Repeated samples ARE NOT "error correcting codes." > >Yes they are, Dick. They are commonly called "repetition codes." See >for example one of the following: > >@book{berlekamp, > title = "{Algebraic Coding Theory}", > author = "{Elwyn R. Berlekamp}", > publisher = "Aegean Park Press", > edition = "revised 1984 edition", > year = "1984"} >@book{wicker, > title = "Error Control Systems for Digital Communication and Storage", > author = "Stephen B. Wicker", > publisher = "Prentice Hall", > year = "1995"} > >> [...] >> And increasing the sample rate DOES NOT "repeat >> samples. > >I agree with this, so the point above is probably moot.But repeating a sample cannot of itself correct errors. What you end up with is two samples of which one, neither or both may be wrong. Of course you can use a repeated sample as somewhere to go and get the correct data if the original sample has already been detected as incorrect. Still a bit of a leap of faith, though. The best error correction method is powerfully dependent on the medium and they way it introduces the errors - single bit errors vs large block errors for example. For a CD it is all quite easy, as there is no low latency pressure which you would have in, for example, a VOIP stream. d -- Pearce Consulting http://www.pearce.uk.com
What's the use of a 192 kHz sample rate?
Started by ●May 3, 2008
Reply by ●May 5, 20082008-05-05
Reply by ●May 5, 20082008-05-05
On May 5, 5:04 pm, Randy Yates <ya...@ieee.org> wrote:> dpierce.cartchunk....@gmail.com writes: > > [...] > > Repeated samples ARE NOT "error correcting codes." > > Yes they are, Dick. They are commonly called "repetition codes." See > for example one of the following: > > @book{berlekamp, > title = "{Algebraic Coding Theory}", > author = "{Elwyn R. Berlekamp}", > publisher = "Aegean Park Press", > edition = "revised 1984 edition", > year = "1984"} > @book{wicker, > title = "Error Control Systems for Digital Communication and Storage", > author = "Stephen B. Wicker", > publisher = "Prentice Hall", > year = "1995"} > > > [...] > > And increasing the sample rate DOES NOT "repeat > > samples. > > I agree with this, so the point above is probably moot. > -- > % Randy Yates % "I met someone who looks alot like you, > %% Fuquay-Varina, NC % she does the things you do, > %%% 919-577-9882 % but she is an IBM." > %%%% <ya...@ieee.org> % 'Yours Truly, 2095', *Time*, ELO http://www.digitalsignallabs.comI dont mean literal repetition.Take for example a sine wave of 10khz and sample it with 1 mhz. One does think of samples getting repeated are atleast they are close.
Reply by ●May 5, 20082008-05-05
nospam@nospam.com (Don Pearce) writes:> On Mon, 05 May 2008 08:04:51 -0400, Randy Yates <yates@ieee.org> > wrote: > >>dpierce.cartchunk.org@gmail.com writes: >>> [...] >>> Repeated samples ARE NOT "error correcting codes." >> >>Yes they are, Dick. They are commonly called "repetition codes." See >>for example one of the following: >> >>@book{berlekamp, >> title = "{Algebraic Coding Theory}", >> author = "{Elwyn R. Berlekamp}", >> publisher = "Aegean Park Press", >> edition = "revised 1984 edition", >> year = "1984"} >>@book{wicker, >> title = "Error Control Systems for Digital Communication and Storage", >> author = "Stephen B. Wicker", >> publisher = "Prentice Hall", >> year = "1995"} >> >>> [...] >>> And increasing the sample rate DOES NOT "repeat >>> samples. >> >>I agree with this, so the point above is probably moot. > > But repeating a sample cannot of itself correct errors. What you end > up with is two samples of which one, neither or both may be wrong.I didn't see that the number of repeated samples was one from Dick's post (or the previous poster). But yes, just doing a single repeat (transmitting two samples for every one) does not buy you anything. -- % Randy Yates % "Though you ride on the wheels of tomorrow, %% Fuquay-Varina, NC % you still wander the fields of your %%% 919-577-9882 % sorrow." %%%% <yates@ieee.org> % '21st Century Man', *Time*, ELO http://www.digitalsignallabs.com
Reply by ●May 5, 20082008-05-05
On Mon, 5 May 2008 05:14:10 -0700 (PDT), rajesh <getrajeshin@gmail.com> wrote:>On May 5, 5:04 pm, Randy Yates <ya...@ieee.org> wrote: >> dpierce.cartchunk....@gmail.com writes: >> > [...] >> > Repeated samples ARE NOT "error correcting codes." >> >> Yes they are, Dick. They are commonly called "repetition codes." See >> for example one of the following: >> >> @book{berlekamp, >> title = "{Algebraic Coding Theory}", >> author = "{Elwyn R. Berlekamp}", >> publisher = "Aegean Park Press", >> edition = "revised 1984 edition", >> year = "1984"} >> @book{wicker, >> title = "Error Control Systems for Digital Communication and Storage", >> author = "Stephen B. Wicker", >> publisher = "Prentice Hall", >> year = "1995"} >> >> > [...] >> > And increasing the sample rate DOES NOT "repeat >> > samples. >> >> I agree with this, so the point above is probably moot. >> -- >> % Randy Yates % "I met someone who looks alot like you, >> %% Fuquay-Varina, NC % she does the things you do, >> %%% 919-577-9882 % but she is an IBM." >> %%%% <ya...@ieee.org> % 'Yours Truly, 2095', *Time*, ELO http://www.digitalsignallabs.com > >I dont mean literal repetition.Take for example a sine wave of 10khz >and sample it with 1 mhz. One does think of >samples getting repeated are atleast they are close. > >Utterly wrong. All the samples are unique. Please go and do some reading on DSP before you continue. d -- Pearce Consulting http://www.pearce.uk.com
Reply by ●May 5, 20082008-05-05
rajesh <getrajeshin@gmail.com> writes:> On May 5, 5:04 pm, Randy Yates <ya...@ieee.org> wrote: >> dpierce.cartchunk....@gmail.com writes: >> > [...] >> > Repeated samples ARE NOT "error correcting codes." >> >> Yes they are, Dick. They are commonly called "repetition codes." See >> for example one of the following: >> >> @book{berlekamp, >> title = "{Algebraic Coding Theory}", >> author = "{Elwyn R. Berlekamp}", >> publisher = "Aegean Park Press", >> edition = "revised 1984 edition", >> year = "1984"} >> @book{wicker, >> title = "Error Control Systems for Digital Communication and Storage", >> author = "Stephen B. Wicker", >> publisher = "Prentice Hall", >> year = "1995"} >> >> > [...] >> > And increasing the sample rate DOES NOT "repeat >> > samples. >> >> I agree with this, so the point above is probably moot. >> -- >> % Randy Yates % "I met someone who looks alot like you, >> %% Fuquay-Varina, NC % she does the things you do, >> %%% 919-577-9882 % but she is an IBM." >> %%%% <ya...@ieee.org> % 'Yours Truly, 2095', *Time*, ELO http://www.digitalsignallabs.com > > I dont mean literal repetition.Take for example a sine wave of 10khz > and sample it with 1 mhz. One does think of > samples getting repeated are atleast they are close.I would not say they are repeated no matter how high you sample. It might help to take an example. Let's say you're transmitting 16-bit signed two's complement samples, and let's say the sample 0000H is transmitted but 8000H is received (a one-bit error in bit position 15). This results in a full-scale negative spike in your input data, which is going to be very noticable. -- % Randy Yates % "She tells me that she likes me very much, %% Fuquay-Varina, NC % but when I try to touch, she makes it %%% 919-577-9882 % all too clear." %%%% <yates@ieee.org> % 'Yours Truly, 2095', *Time*, ELO http://www.digitalsignallabs.com
Reply by ●May 5, 20082008-05-05
On May 5, 5:26 pm, Randy Yates <ya...@ieee.org> wrote:> nos...@nospam.com (Don Pearce) writes: > > On Mon, 05 May 2008 08:04:51 -0400, Randy Yates <ya...@ieee.org> > > wrote: > > >>dpierce.cartchunk....@gmail.com writes: > >>> [...] > >>> Repeated samples ARE NOT "error correcting codes." > > >>Yes they are, Dick. They are commonly called "repetition codes." See > >>for example one of the following: > > >>@book{berlekamp, > >> title = "{Algebraic Coding Theory}", > >> author = "{Elwyn R. Berlekamp}", > >> publisher = "Aegean Park Press", > >> edition = "revised 1984 edition", > >> year = "1984"} > >>@book{wicker, > >> title = "Error Control Systems for Digital Communication and Storage", > >> author = "Stephen B. Wicker", > >> publisher = "Prentice Hall", > >> year = "1995"} > > >>> [...] > >>> And increasing the sample rate DOES NOT "repeat > >>> samples. > > >>I agree with this, so the point above is probably moot. > > > But repeating a sample cannot of itself correct errors. What you end > > up with is two samples of which one, neither or both may be wrong. > > I didn't see that the number of repeated samples was one from Dick's > post (or the previous poster). But yes, just doing a single repeat > (transmitting two samples for every one) does not buy you anything. > -- > % Randy Yates % "Though you ride on the wheels of tomorrow, > %% Fuquay-Varina, NC % you still wander the fields of your > %%% 919-577-9882 % sorrow." > %%%% <ya...@ieee.org> % '21st Century Man', *Time*, ELOhttp://www.digitalsignallabs.comit does help the signal to get reconstructedl more accurately.
Reply by ●May 5, 20082008-05-05
On May 5, 8:34 am, rajesh <getrajes...@gmail.com> wrote:> On May 5, 5:26 pm, Randy Yates <ya...@ieee.org> wrote: >> But yes, just doing a single repeat (transmitting two >> samples for every one) does not buy you anything. > > it does help the signal to get reconstructedl more accurately.Not if the waveform is sampled at grater than 2 times the bandwidth, it does not. Once you sample greater than the Nyquist limit, NO extra information is gathered, not matter HOW much more your sample. The resulting output waveform is the same whether you sampled at 2..01times the bandwidth or 2000000 times the bandwidth. The output waveform DOES NOT get any more accurate. You've invoked Shannon. How about going and actually READING and UNDERSTANDING it not?
Reply by ●May 5, 20082008-05-05
"Oli Charlesworth" <catch@olifilth.co.uk> a �crit dans le message de news: 3401ea82-38fc-4ab0-8778-e63cdd3be59f@a70g2000hsh.googlegroups.com... On May 5, 12:18 pm, "Robert Lacoste" <use-contact-at-www-alciom-com- for-email> wrote:> "Green Xenon [Radium]" <gluceg...@excite.com> a �crit dans le message > denews: > 481becfe$0$5141$4c368__BEGIN_MASK_n#9g02mG7!__...__END_MASK_i?a63jfAD$z__@roadrunner.com... > - However if you use a 192Kbps sampling rate then the required > performances > on the low pass filter are drastically relaxed. This filter can keep a > corner frequency at 16 or 20KHz, but even a 6th order filter will provide > a > at 86dB attenuation at 192/2=96KHz... > > And as a 192Ksps sampling rate is far cheaper to build than a very very > good > low pass filter... That's the beauty of oversampling...>Oversampled conversion does not require one to *store* information at >the oversampled rate.Fully right, but it is a low cost solution if you want to avoid the cost of a digital low pass filter & decimator... Robert
Reply by ●May 5, 20082008-05-05
Robert Lacoste wrote:> "Oli Charlesworth" <catch@olifilth.co.uk> a �crit dans le message de news: > 3401ea82-38fc-4ab0-8778-e63cdd3be59f@a70g2000hsh.googlegroups.com... > On May 5, 12:18 pm, "Robert Lacoste" <use-contact-at-www-alciom-com- > for-email> wrote: >> "Green Xenon [Radium]" <gluceg...@excite.com> a �crit dans le message >> denews: >> 481becfe$0$5141$4c368__BEGIN_MASK_n#9g02mG7!__...__END_MASK_i?a63jfAD$z__@roadrunner.com... >> - However if you use a 192Kbps sampling rate then the required >> performances >> on the low pass filter are drastically relaxed. This filter can keep a >> corner frequency at 16 or 20KHz, but even a 6th order filter will provide >> a >> at 86dB attenuation at 192/2=96KHz... >> >> And as a 192Ksps sampling rate is far cheaper to build than a very very >> good >> low pass filter... That's the beauty of oversampling... > >> Oversampled conversion does not require one to *store* information at >> the oversampled rate. > > Fully right, but it is a low cost solution if you want to avoid the cost of > a digital low pass filter & decimator...The cost is in any case low, and a little extra cost in the acquisition chain is amply repaid in reduced storage cost of all the copies. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●May 5, 20082008-05-05
On May 5, 5:54�pm, dpierce.cartchunk....@gmail.com wrote:> On May 5, 8:34 am, rajesh <getrajes...@gmail.com> wrote: > > > On May 5, 5:26 pm, Randy Yates <ya...@ieee.org> wrote: > >> �But yes, just doing a single repeat (transmitting two > >> samples for every one) does not buy you anything. > > > it does help the signal to get reconstructedl more accurately. > > Not if the waveform is sampled at grater than 2 times the > bandwidth, it does not. Once you sample greater than the > Nyquist limit, NO extra information is gathered, not matter > HOW much more your sample. The resulting output waveform > is the same whether you sampled at 2..01times the bandwidth > or 2000000 times the bandwidth. The output waveform DOES > NOT get any more accurate. >There is no gurantee that the audio signal is bandlimited. If we cant percieve freq higher than 20k doesnt mean that they are not present> You've invoked Shannon. How about going and actually > READING and UNDERSTANDING it not?. i will do that
