Engineering Electronic Projects on Echo Cancellation System is seen in telephonic systems and is defined as the process of eliminating echo from voice communication thus improving the voice quality. Acoustic and hybrid echo are two types of echo relevant in telephony. This process firstly recognizes the original signal transmitted and then concentrates on the echo part and is removed by subtraction.
Acoustic echo emanates from a loudspeaker in situations when the microphone is in the same room. Such echo is seen in hands-free phone systems in cars, conference phones. It is also present when there are far end talkers in a room conversing. It is very important to cancel this echo as it retraces back in the original signal path serving as a distraction.
The Engineering Electronic Projects on Echo Cancellation System dealt with in this project concentrates on acoustic echo. Firstly a far-end signal is transmitted to the system. This signal is replicated by the speaker present in the room. At the same time a microphone also picks this signal which results in the production of acoustic echo. Then the far-end signal is filtered out and made to match the near-end signal by delaying it. This is followed by subtraction of far-end signal from the near-end signal. The final signal is a signal free of any sort of echo produced earlier by the speaker.
The incorporation of echo cancellation directly into the circuit roughly translates that the echo cancellers in used can be easily switched ON/OFF through a call-by-call basis thereby eliminating the need trunk groups for voice and data calls. In the current telephony systems, echo cancellers are used in handheld communications through software based voice engine which performs the function of acoustic echo as well as any other echo present. The main application of this project is in voice messaging as well as voice response systems which use speech input for its operation.
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