JPS5791457A - Frequency analyzer - Google Patents

Abstract

PURPOSE:To detect signals at low error rates both in the case of only one signal and when >=2 signals are inputted simultaneously and perform accurate frequency analysis by setting the thershold level of threshold detectors low through plural detectors. CONSTITUTION:The input signal converted to a common intermediate frequency signal in a frequency conversion circuit 30 is applied to amplitude limiting amplifiers 6a- and plural detectors 10a- simultaneously. The outputs from the amplifiers 6a are detected with threshold detectors 8a- via narrow band BPFs 7a-, and the frequency of the input signal is analyzed by a discrimination circuit 9. On the other hand, the plural detectors 10- generate detection outputs and set the threshold levels of the detectors 8a- low only when plural waves are detected. Thereby, each of the plural waves amplitude limited collectively with the amplifiers 6a- is surely detected with the amplifiers 8a-. Hence, the signals are detected with low error rates both in the case of only one signal and when >=2 signals are inputted simultaneously, whereby the accurate frequency analysis is accomplished.