| 摘要 |
<p>A loudspeaking telephone network has an echo cancelling device (EC) for serving a number of telephones. Each telephone has a microphone (MIC) and a loudspeaker (LS) which are separately connectable by transmission channels to supply voice signals to the echo cancelling device and to receive voice signals from the echo cancelling device. In this way high quality echo cancelling is provided for any telephone on demand that is connectable to the network and the relatively high cost of echo cancelling devices is shared in effect by many telephones.</p> |
