VERFAHREN ZUM HOCHGENAUEN MESSEN VON PHASEN- UND FREQUENZDIFFERENZEN

摘要

The frequency/phase meter consists of a reference oscillator and measured signal. Both signals are fed to dividers. The outputs of these are fed to a phase detector. This can be a flip-flop with reference signal fed to its set input and measured signal fed to its reset input. The output is a signal whose pulse width is proportional to the phase difference between the inputs. The output drives a frequency counter which provides an average pulse width measurement during a certain gating time. This time is a whole multiple of the pulse width of the phase signals. The variation with time of the averaged value is determined over a measured interval. From this calculation the average relative frequency diference between the two signals is obtained by division by the second time interval. This interval is a whole multiple of the first gating time.