I'm looking for a way to digitally modify the gain of an amplifier/DAC/codec in very precise intervals (0.1-0.2dB). My current process involves generating a sine wave with a DAC and then running it through an audio amplifier before playing it on a speaker. I wish to digitally adjust the gain of either the DAC, the amplifier, or some other portion of the circuit.

Practically all of the class A/AB/D audio amplifiers I've looked into have step sizes of 0.5-1dB. After inquiring at Texas Instruments, an employee recommended a codec with miniDSP/Class D amp (TLV320AIC3263), which does meet my requirements (0.1dB/step). While this is probably my best option so far, it's a bit outside of my scope and I feel there may be a simpler solution.

Can you think of any alternative ICs that meet these specs or this type of codec the best approach?

  • 1
    This might be a better fit for dsp.stackexchange.com though check their stance on product recommendations first.
    – Tetsujin
    Sep 22 at 8:05

The easiest, and possibly the most precise would be to adjust the amplitude of the generated sine wave while still in the digital domain.

In analog domain, 0.1 dB change of power corresponds to 2% change of signal amplitude. This seems like precision that can be realistically achieved, but details will depend on your exact requirements.

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