Speech Enhancement - Digital Speech: Coding for Low Bit Rate Communication Systems - page 401

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0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Speech detection error-rate of VAD, E d

MD HD SD Theoretical limit

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0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Speech detection error-rate of VAD, E d

MD HD SD Theoretical limit Unprocessed

Figure 11.17 Comparison of SEGSNR improvement and ISD against the speech-
detection error-rate of VAD for vehicle noisy speech of 10 dB SNR

and electrical echo, generated at the two-to-four wire conversion hybrid
transformer due to imperfect impedance matching. Here, we will develop
cancellation for the electrical echowhichwill be equally applicable for acoustic
echo cancellation.
The source of electrical echo can be understood by considering a simplified
block diagram of a connection between a pair of subscribers, S1 and S2,