Perpetual Pulsewidth Counter

Abstract

The Perpetual Pulsewidth Counter (PPWC) provides an excellent capability for precise pulsewidth or time-interval detection. This efficient and inexpensive circuit solution will overcome the known difficulties of conventional pulsewidth detectors. Its ability to perpetually and precisely detect single pulsewidths makes it possible to build a precise pulse sorter with a continuous number of windows. Additionally, the PPWC has a short "dead time" (the minimum interval, following a pulse, during which a circuit is incapable of repeating a specified performance) which allows it to detect pulses with very small spaces between each pulse. This counter can be employed in precise pulsewidth sorting with a continuous (perpetual) number of stages in FM demodulation, in frequency, or pulsewidth discrimination and/or detection, as well as in decoding for dual-tone, multifrequency telephone communication systems (DTMF), interpreting sets of pulses and automatically adjusting bandwidth for recognition of codes, etc. A hypothetical 28-pin chip for "sorting" 16 pulsewidth ranges is described in this paper.