| 摘要 |
<p>DIGITAL TRANSMITTER A solid state remote monitoring transmitter which transmits a 40 bit word that contains status information about a transformer via the secondary of a power distribution network to a central receiver associated with the primary (feeder) cable supplying the transformer. A program card specifies the carrier signal frequency and the identification of the transmitter. Multiple analog inputs are switched through a multiplexer to an A/D converter, the output of which is stored in a shift register to form the 40-bit word. The word is DPSK coded by clock pulses in synchronism to the 6OHz zero crossings of the AC power source and amplified by an unregulated power supply which is also powered by the AC power source. The phase transitions of the DPSK coded word occur at the zero crossings dimînishing any transients in the transmitter circuitry which would be caused by the phase transitions.</p> |
