[sdiy] Good 16 bits A/D choice for mono audio recording

[Eric Brombaugh]

J-P,

There are lots of decent SPI ADCs out there that would work just fine 
for 44kHz, 16-bit sampling. Linear Tech, ADI and TI make a wide variety 
of them. 16-bit parts are a bit harder to find than 12-bit parts though.

The on-chip 12-bit ADCs in the PIC series parts will typically exhibit 
rather poor INL (Integral Nonlinearity) which reduces the ENOB 
(effective number of bits). They also tend to be pretty sensitive to 
noise in the VDD & Vref lines. This means that the 12-bit ADC will have 
an SNR that's closer to that of a 10-bit converter. If you can live with 
60dB of SNR in your audio then you're probably OK. Otherwise you'd be 
wise to choose a converter that can guarantee better quantization noise.

Eric

jean-pierre.desrochers at ville.quebec.qc.ca wrote:
> It's good to see someone is still
> there to help...
> I'm looking for SPI for less pin count
> on the PIC cpu that will do the readings.
> I saw PIC18's with 12bits A/D but I fear some
> A/D noise from it since this is audio I read.
> If I go 12bits would the PIC18 be a good choice anyway?
> I think external 16bits A/D would do better..?
> J-P Desrochers
> 
> -----Message d'origine-----
> De : Eric Brombaugh [mailto:ebrombaugh at earthlink.net]
> Envoyé : 25 mai 2007 11:33
> À : synth-diy at dropmix.xs4all.nl
> Objet : Re: [sdiy] Good 16 bits A/D choice for mono audio recording
> 
> 
> jean-pierre.desrochers at ville.quebec.qc.ca wrote:
> 
>> I need to pick a good A/D converter for sampling
>> the surrounding audio. I found the Analog Devices AD7684.
>> It shows a suitable S/N ratio and is single supply
>> like I need.
> 
> What sort of interface are you looking for?
> 
> * Parallel
> * SPI
> * I2S
> * other?
> 
> Eric
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