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Signal to Noise Ratio (SNR) Measurement

Posted: February 24th, 2017, 1:58 am
by mei123
I would like to measure SNR of an acoustic signal where the frequency of the signal is 37.5 kHz. Theoretically, this can be done by performing FFT on a sampled data of the signal. My question can I directly pass the data into the Mojo board? Do I need an external ADC?

Thank you.

Re: Signal to Noise Ratio (SNR) Measurement

Posted: February 28th, 2017, 1:10 pm
by embmicro
If you want to do any accurate analog measurements like SNR, I'd recommend using an external ADC. You can use the ADC from the AVR but the default firmware isn't really setup for this kind of thing and the time between samples may not be perfectly fixed. You could modify the firmware to sample things more regularly or use an external ADC.

Actually, I just scoped the datasheet for the ATmega32U4 and it only can sample up to 15KSPs at 10-bit samples so you'll definitely need an external faster one.