Accurate detection of idle dual tone alarm signal (see PDF for details!)

Probe domestic high frequency needle JKT-50L high frequency needle with 3 probes

Test - lowercase jpg

Kaixin micro test

Summary:

This paper introduces a method for accurately detecting the idle dual tone alarm signal, and gives specific circuits and application examples. The circuit not only has accurate detection, but also has great flexibility, and has certain reference value for detecting different standard audio signals. Welcome to download and share!

The idle-mode dual-tone alarm signal detection mechanism described in this paper has been widely used in telephone systems. It is not only highly accurate, but also simple in circuit and flexible. According to the difference of the detection signal frequency, combined with the detection accuracy, and timely adjusting the counter value of each counter, the detection of different frequency signals can be realized.