| 摘要 |
A digital demodulator for converting PCM data from PSK to NRZ-L and to Bi phi -L. The demodulator is composed of standard integrated logic circuits. The key to the demodulation function is a pair of cross-coupled one-shot multivibrators 11 and 12 which with a flip-flop 13 produce the NRZ-L. In order to generate Bi phi -L, the PSK carrier is constrained to be 2N times the data bit rate. If NRZ-L is all that is required, the circuitry is greatly simplified and the 2N times bit rate constraint can be removed from the carrier. A flip-flop 15, an OR gate 14, and AND gate 16 and a binary counter 17 generate the bit rate clock BTCK for the NRZ-L. The remainder of the circuitry is for converting the NRZ-L and BTCK into Bi phi -L.
|
