Remember the Nyquist-Shannon theorem! So, either you have a highly sophisticated anti-aliasing filter in front of your ADC, then you can sample at about 44kHz, or you need oversampling technique, where you sample at about 176kHz or even much more. Oversampling allows you to work with a less sophisticated low pass filter, not providing extreme high damping at the half of 44kHz.

Behind the DAC you will need, of course, again some low pass filtering, which is called here 'restauration' filter. In many systems restauration filtering is partially done by a digital FIR-filter.

If your transmission channel is bandwidth limited you will still need some digital compression technique...

Kai