Patent ID: 6169760
Filing Date: 2001-01-02
Classification: G01R

Abstract:
A method for finding the frequency of a test applied signal, comprising the steps of providing a signal filter having, as a function of frequency, a signal pass band frequency range wherein a high fraction of an initial amplitude of an introduced signal passes through the signal filter, a signal stop band frequency range wherein a low fraction of the initial amplitude of the introduced signal passes through the signal filter, and a signal filter skirt band frequency range between the signal pass band and the signal stop band, wherein an intermediate fraction of the initial amplitude of the introduced signal passes through the signal filter, the intermediate fraction varying with the frequency of the introduced signal;introducing the test applied signal into the signal filter, the test applied signal having a frequency which lies within the signal filter skirt band frequency range; measuring the a transmitted amplitude of the test applied signal after the test applied signal has passed through the signal filter; and utilizing a transmitted amplitude as an indicator of the frequency of the test applied signal, wherein the step of utilizing includes the steps of establishing a signal filter calibration relation of the amplitude of a transmitted signal in the signal filter skirt band as a function of the frequency of an applied signal, and determining the frequency of the test applied signal from the amplitude of the test applied signal and the signal filter calibration relation.