| 摘要 |
<p>A dual speed, full duplex modem (Fig. 6) for transmitting and receiving data on a dial-access telephone line includes a signal processor (26, 38) for storing samples corresponding to a mu-law compressed sinusoidal waveform, for selecting samples at intervals determined by the modem operating mode to synthesize a signal for modulating by data for transmission, and for autocorrelating a received signal at a frequency determined by the operation mode to recover data from the received signal. The signal processor includes configuring input ports, and a microcomputer receives instructions related to the modem operating mode to output a mode-configuring word to the configuring inputs. Conversion from the signal processor's digital output to the analog signal to the line and from the line's analog signal to the signal processor's digital input takes place through two time-division multiplexed coder-decoder (D/A 30 and A/D 34).</p> |
