electronic avstandsmetare with styroscillator and in phase with the working servooscillator

摘要

An infra-red telemeter comprises a pilot oscillator 1 and a controlled oscillator 2 kept in phase with the pilot oscillator 1. The controlled oscillator 2 provides the modulation frequency for transmission, either directly for fine measurement or via a counter 11 which divides by M. for coarse measurement, while the pilot oscillator 1 provides a heterodyne frequency, either directly or after division by N in a counter 17, respectively. After the received modulation signal has been mixed with the heterodyne frequency, a phase detector 18 compares the phase of the mixed signal with the phase of a reference low frequency obtained by the frequency of oscillator 1 being divided by H in counter 17. The phase servo loop operates continuously, in the case of both fine and coarse measurement.