I have to measure the capacitance of three capacitive sensors which are placed together. AD7745 seems ideal for the application. But if I use 3 different excitation sources(one in each chip of AD7745),even if there is a small difference in the frequencies of these excitation voltage, there is a chance of beating, since the cables from all these sensors are bunched together. So is it possible to use an external excitation source(Vdd/2 ; 32 kHz) common for all these sensors?
The output from each of the sensor goes to the CIN pin of each AD7745.
NB: I am planning to use it with range extension circuit.