What's the use of a 192 kHz sample rate?
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From: Oli Charlesworth on 5 May 2008 08:56 On May 5, 1:26 pm, rajesh <getrajes...(a)gmail.com> wrote: > > "Why does DVD-Audio use 192 kHz sample rate? What's the advantage over > 44.1 kHz? Humans can't hear the full range of a 192 kHz sample rate? " > > He means to say that why 44.1khz is not used on DVD's? > > Thats exactly what i answered Ok, even if we're talking about a single storage medium, 192kHz audio isn't going to be reproduced any better than 44.1kHz audio written to the same media. Think of the errors as additive white noise superimposed on the audio signal (although that's not the physical mechanism by which the errors arise, the resulting error signal will be white). In the 192kHz case, 192/44.1 times as many physical errors will occur, so the total energy of the error signal will be 192/44.1 times as high. However, this is distributed over a signal bandwidth that's 192/44.1 times as wide, so the PSD will be the same in each case. Therefore, the total energy in the audible band (0-20kHz) will be the same. -- Oli
From: Robert Lacoste on 5 May 2008 08:57 "Oli Charlesworth" <catch(a)olifilth.co.uk> a �crit dans le message de news: 3401ea82-38fc-4ab0-8778-e63cdd3be59f(a)a70g2000hsh.googlegroups.com... On May 5, 12:18 pm, "Robert Lacoste" <use-contact-at-www-alciom-com- for-email> wrote: > "Green Xenon [Radium]" <gluceg...(a)excite.com> a �crit dans le message > denews: > 481becfe$0$5141$4c368__BEGIN_MASK_n#9g02mG7!__...__END_MASK_i?a63jfAD$z__(a)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
From: Jerry Avins on 5 May 2008 09:15 Don Pearce wrote: > On Mon, 5 May 2008 04:36:01 -0700 (PDT), rajesh > <getrajeshin(a)gmail.com> wrote: > >> On May 5, 4:21 pm, nospam(a)nospam.com (Don Pearce) wrote: >>> On Mon, 5 May 2008 04:15:59 -0700 (PDT), rajesh >>> >>> <getrajeshin(a)gmail.com> wrote: >>>> On May 5, 3:46 pm, dpierce.cartchunk....(a)gmail.com wrote: >>>>> On May 5, 4:05 am, rajesh <getrajes...(a)gmail.com> wrote: >>>>>> Remember the shannon's theorem which places a >>>>>> trade off between error correcting codes and bandwidth. >>>>> Again, pure nonsense. Shannon's theorem >>>>> never discusses error correcting codes AT ALL. >>>> hi pierce , >>>> BTW from which school did u learn DSP? >>> Rajesh, please take some advice and don't do this. He is going to rip >>> you to pieces and embarrass you badly. >>> >>> d >>> >>> -- >>> Pearce Consultinghttp://www.pearce.uk.com >> Here is the coz for mis interpretation of my opinions. >> >> I am not comparing two different discs of two different capacities at >> all. >> >> I am comparing, given the same high capacity disc, which sampling rate >> can cope better with errors. >> >> And the answer is the one with which is oversampled. >> > Do you even know what oversampling is? You won't find it on any disc - > it is a function of the front end of an ADC. > > And of course they are ALL oversampled, no exceptions, ever. > >> >> say if u are comparing 44.1 kHz CD and a 196kHz DVD then they both >> cope with errors equally.there is no doubt about this. >> >> But then in the later case you are not comparing apples to apples. >> > > The way they cope with errors is a function of the error > detection/correction schemes they use. And the packing density. If 192 samples are packed into the same space as 44.1, then a scratch of a particular size destroys more than 4 times as much data at the higher density. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
From: Jerry Avins on 5 May 2008 09:28 Robert Lacoste wrote: > "Oli Charlesworth" <catch(a)olifilth.co.uk> a �crit dans le message de news: > 3401ea82-38fc-4ab0-8778-e63cdd3be59f(a)a70g2000hsh.googlegroups.com... > On May 5, 12:18 pm, "Robert Lacoste" <use-contact-at-www-alciom-com- > for-email> wrote: >> "Green Xenon [Radium]" <gluceg...(a)excite.com> a �crit dans le message >> denews: >> 481becfe$0$5141$4c368__BEGIN_MASK_n#9g02mG7!__...__END_MASK_i?a63jfAD$z__(a)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. �����������������������������������������������������������������������
From: rajesh on 5 May 2008 09:44
On May 5, 5:54 pm, dpierce.cartchunk....(a)gmail.com wrote: > On May 5, 8:34 am, rajesh <getrajes...(a)gmail.com> wrote: > > > On May 5, 5:26 pm, Randy Yates <ya...(a)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 |