Double ADC samplerate

Started by Vinzz 2 years ago3 replieslatest reply 2 years ago209 views

Hi guys,

I wonder if it is possible to get 192kHz samplerate out of a 96kHz ADC.

I need to capture a mono signal with 192kHz samplerate. What if I use a 96kHz ADC, connect both L+R inputs and set the samplerate to 96kHz? The samplerate is 96kHz but I get a 192000 samples/sec buffer.

The word selection of the ADC switches between L & R so the ADC buffer results in double the samples.

Should this be possible?

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Reply by dudelsoundApril 5, 2022

The rate sounds typical for an audio application, so I assume you are talking about a sigma delta audio converter. These usually sample both channels at the same instance, not consecutively. So - even though you get twice the data - it will not be the mono-signal sampled at twice the frequency, I'm afraid.

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Reply by DansanApril 5, 2022

That will only give you double the precision, and lower your noise floor by 3dB, I expect.

You can't get a higher sample rate that way because in a typical ADC you need a decimation filter which limits your bandwidth.  Interleaving channels with a delay might get you double the samples but no extra bandwidth so it would be useless.

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Reply by engineer68April 5, 2022

The question is, what are the 192kHz intended for. Is it to transport higher frequencies like e.g. 80kHz which a 96k signal cannot transport? You will need a ADC with an adjusted AA-filter anyway which will not be available with a common sound card.

And if (in the other case) you want to go with common audio frequencies, stepping to 192k  fs ist not a great benefit, so you can simply upconvert.

Using both channels to gain the theoretical 3dB is not a good idea, because with common sound cards, you will have offset in between the two channels and als experience different amplification gains too which both requires further treatment to really have a benefit.