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Re: OT: 24Bit/96Khz vs 16Bit/ 44.1Khz recording



Hi Andy,

I hop I am understanding  your question..  The word width produced is 24 
bits at any of the available sample rates. 

There are no effective 1bit PCM A/D converters (DSD is a different 
matter). So in a sense it is an "apple and oranges" situation, most over 
sampling converters use a 4 bit sigma-delta type converter but the 
resulting output is 24 bit resolution. In the case of the 96 I/O streams I 
run in my mix room, the converter chip is capable of around 123-126dB s/n 
rather than the theoretical 144dB that 24 bits could represent.  This is 
due to purely Physical limitations, which dictate for example that you 
cannot design a useful gain stage with less than  -129dB of noise. 


Sent from my iPad Nano

On Dec 16, 2011, at 9:25 AM, andy butler <akbutler@tiscali.co.uk> wrote:

> 
> Whose on first base?
> 
> 
> I didn't mean that. 
> rather to question what the *numerical* bit depth of the 12.288Mhz 
> sampling would be.
> 
> I was prompted to doing that by looking up "how does an oversampling ADC 
> work?"
> and reading that the sampling was at 1bit.
> 
> 
> Now, I'm easily convinced that sampling at 16bit 12.288Mhz
> and digital filtering to 44kHz would rid of aliasing very easily,
> ....but not so convinced (yet) knowing about the 1 bit sampling.
> 
> andy
> 
> 
> 
> 
> Charles Zwicky wrote:
>> Bit depth is independent of sample rate. The bit depth simply 
>> determines the number of discreet amplitude levels which can be 
>> quantified at each sample. The number is expressed as an exponent of 2 
>> (because each bit is binary - a 1 or a 0).  16 bits = 2^16 = 16,535 
>> amplitude values, 24 bits = 2^24
>> =16,777,216...!
>> Sent from my iPad Nano
>> On Dec 16, 2011, at 4:42 AM, andy butler <akbutler@tiscali.co.uk> wrote:
>>> Charles Zwicky wrote:
>>> 
>>>> 256 x 48khz  =  128 x 96khz  =  64 x 192khz = 12.288Mhz
>>>> In other words, the input is sampled at rate of 12.288Mhz independent 
>>>> of the system sampling rate.
>>>> For one thing, this means that aliasing is nonexistent even at a 
>>>> "44.1khz" sample rate.  
>>> 
>>> Interesting,
>>> what's the bit depth at the 12.288Mhz rate?
>>> 
>>> andy
>>> 
>