FIG. 9B is a circuit diagram of an exemplary track and hold circuit suitable for use in the time-division multiplexed signal processing circuitry of FIG. 9A; the track and hold circuit includes an input buffer (provided by a 0.01 uF capacitor and 5K ohm resistor for AC coupling, an op-amp configured as a voltage follower, and 10K ohm resistor coupled between the output node of the op-amp and groun