Abstract: A transducer (23) for producing a digital output signal proportional to a change in a sensed physical parameter includes first and second pairs of series-connected resistors (24, 25 or 26, 28). The electrical resistance of at least one of these resistors is variable in response to a change in the sensed parameter. The transducer also includes sine wave generators (31, 32) for applying first and second sine waves across the first and second pairs, respectively. However, these first and second exciting voltages are phase-shifted relative to one another by a constant phase angle. The voltages between the resistors of each pair are vector-summed. The phase angle of this vector-sEed signal is compared with the phase of the reference sine wave, and a pulse-width-modulated waveform is produced.