Discovering echo in call recordings

Signal reflection (echo) occurs when a signal is transmitted along a transmission medium, such as a copper cable or an optical fiber. Some of the signal power may be reflected back to its origin rather than being carried all the way along the cable to the far end. This happens because imperfections in the cable cause impedance mismatches and non-linear changes in the cable characteristics. These abrupt changes in characteristics cause some of the transmitted signal to be reflected. The ratio of energy bounced back depends on the impedance mismatch. Mathematically, it is defined using the reflection coefficient.
In telecommunications, the reflection coefficient is the ratio of the amplitude of the reflected wave to the amplitude of the incident wave. In particular, at a discontinuity in a transmission line, it is the complex ratio of the electric field strength of the reflected wave to that of the incident wave.

We would like to welcome you try out our echo detection in call recordings algorithm using a very simple web service at

If echo is present in provided wave file (8kHz, 16 bit, Mono) then result of analysis will report echo delay, e.g.:

Echo delay: 0.2 s (-7.096 dB)

If no echo detected in the wave file result will be:

No peaks (good coefficients lost)

You are welcome to contact me on LinkedIn or via our web site at to lear how echo detection is implemented in our real-time call quality monitoring system.



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