Re: [Xylo-SDR] A/D anti-aliasing filters

[Lyle Johnson <kk7p@wavecable.com>]

> The circuit in the TI data sheet is a combination single-ended to 
> differential converter, and a lowpass filter.

Figure 44 is in deed a single-ended to differential converter, followed 
by a differential amp that has shaped characteristics which are used in 
conjunction with the ADC itself to derive the overall noise performance. 
 More information is on the TI OPA1632 data sheet.

See also app note "Gain Scaling and Audio Performance of the PCM1804", 
slea003.pdf dated May, 2002 for more information.

It may be that you don;t need this for the QSD, but I suspect you'll 
lose a few dB in overall performance.  On the other hand, you may not :-)

Enjoy!

Lyle KK7P