ADAU1701 tool block VCO frequency resolution

Hi BerndS,

If you input a 5.23 number, then an input of 0.5 will give you an output of Fs/4, meaning the output signal will use exactly 4 samples per waveform cycle.

An input of 0.999999... (approaching 1.0) will give you an output of Fs/2, but the current cell will not be able to output a signal exactly at Fs/2.

So, for a sample rate of 48 kHz, the highest frequency the cell can output is 23.99999... kHz, but it seems that it will not output 24 kHz. You're able to approach (but not quite reach) the limit of Fs/2.

Hi Brett,

so it means you'll have frequency steps of 24.000 / 2^24 linear spaced ( 1.4305..mHz ) ?

regards

Hi Bernd,

Yes, that's right. This is thanks to the interpolation that takes place using the ROM sine table.