Abstract: A pressure measuring system which includes a pressure sensitive capacitor and a reference capacitor, a source of external excitation connected to the sensing capacitor, the reference capacitor being connected to a feedback signal generating circuit and the output from said capacitors being summed by a summing junction to produce an error signal. A phase sensitive demodulator is connected to receive the error signal and input same to a feedback signal generating circuit to generate the feedback signal for the reference capacitor. The feedback signal generating circuit includes a computing circuit for generating a digital signal corresponding to the magnitude of said feedback signal required to null said sensing capacitor signal to thereby provide a measurement of pressure.