Infralow-frequency digital phase meter

Digital methods of measuring phase shifts in the infralow-frequency range are most effective, in terms of high speed and insensitivity to frequency changes in the input signal, but the output signal depends on the frequency of the input signal voltage. This drawback can be overcome by various means such as synchronization or special correction. Precise multiplication of the input signal frequency by a given factor and subsequent filling with the high-frequency of the entire time interval generated by a start-stop module will yield the optimum performance characteristics without additional calibration or correction. Such an instrument consists of two amplifier-limiter stages producing rectangular pulses with a 0.5 duty factor, a mode selector shaping pulses with either of the corresponding two durations, a high-frequency frequency signal generator, a trigger, a frequency divider, a digital period meter, a transcriber, a reversible counter, an OR circuit, two AND circuits, a counter, and three driven multivibrators. In order to cover a wide frequency range, it is necessary to use multidigit devices or, simpler, to generate a set of frequencies not higher than a certain multiple of the pulse repetition rate at the mode selectro output.