| 摘要 |
<p>A high speed modem for simultaneously transmitting both voice and precoded digital data signals over a single communication channel. The modem is operable to combine a voice signal with a precoded digital data signal for transmission at high speeds, high power levels and low distortion previously attainable by high speed data-only modems. The voice signal is processed using conventional data processing techniques to produce a voice signal and a control signal containing information relating to the coding of the voice signal. The control signal is multiplexed and mapped for transmission with the digital data. Selected bits of the multiplexed data are used to define the rotation of the digital data and to rotate the voice vector. The digital data is precoded to compensate for and minimize noise in the communication channel. The rotated voice vector and the precoded digital data are then combined and transmitted. At a remote location, the transmitted signal is received by a receiving modem and is filtered and separated to thus recover the individual coded signals. The separation of the coded voice signal from the precoded digital data signal is performed prior to reconstruction of the precoded digital data signal. The coded voice signal is then de-rotated. The coded voice and precoded digital data signals are then individually decoded to retrieve the voice and data signals that originated at the transmitting modem. <IMAGE></p> |
