A current- or voltage-to-frequency converter is described for converting analogue signals into a pulse form in which the pulse repetition frequency is proportional to the instantaneous signal amplitude. The conversion is linear to within 0·01% over the frequency range 0-10 kHz (or 0-1 kHz), and to within 0·1% up to 50 kHz. Thermal stability is comparable.

The circuit action is based on continuous integration of the input signal, and the converter may be used as an interface in signal processing, or as an integrator, or for converting a digital frequency meter into a digital voltmeter with 10 μV resolution. It may also be used in reverse as an accurate count-rate meter (frequency-to-voltage conversion).