Where you partition a system changes with technology. Look at software defined radios. If you don't need versatility, analog design wins. [Simple and low power.] If you need to support a plethora of modulation options, SDR wins.
I have mentioned on this NG more than once about the DTMF dialer we put in a modem chipset that used a CORDIC. It was insanely accurate, way beyond the requirements. The only reason we did it was the DAC, uP and CORDIC were needed in the system for other functions, and dialing was done at a time when those system resources were not in use.
I don't believe the book you want exists.