Testing device including low-pass filter with automatically switching function

Abstract

A testing device including low-pass filter with automatically switching function is disclosed in the present invention, comprising: a control circuit used to control the operation of the testing device and provide a reference frequency (Fr); a frequency detection circuit, connected to the input end and the control circuit and used to output a high frequency control signal; a low-pass filter connected to the frequency detection circuit, used to filter the testing signal of the input end to output a frequency signal; a frequency evaluation circuit connected to the control circuit and to the frequency signal outputted from the low-pass filter, the frequency evaluation circuit outputting a medium frequency control signal to the low-pass filter and outputting a frequency testing value to a display at the same time; and a voltage measuring circuit, connected to the low-pass filter and the control circuit and used to output a voltage measuring value to the display.

Dependencies are inferred from the claim text.