Patent ID: RE41739

Claim:
A powerline pulse position modulated communication transmitter comprising: first and second connections for connecting to an AC powerline; a chargeable capacitor and a switch in series therewith coupled to said first and second connections for connection in parallel to the powerline; a digital control integrated circuit; a zero voltage crossing detector circuit coupled to said first and second connections and to said digital control integrated circuit; a signal source to actuate said digital control integrated circuit, said digital control integrated circuit being coupled to said switch in series with said capacitor to actuate said switch in a series of half cycles of the AC powerline in order to produce a series of pulses in said series of half cycles; said pulses comprising at least one preliminary synchronization reference pulse referenced to the zero crossing time followed at least one half cycle later by one or more data pulses which are within about 1,000 microseconds of a following zero crossing in which each data pulse encodes a binary number determined by the relative position of said data pulse to said preliminary synchronization reference pulse; said digital control integrated circuit being coupled to said switch in series with said capacitor to actuate said switch in one of a predetermined number of a plurality of signal time positions referenced to said reference pulse position in the powerline to discharge said capacitor into the powerline to produce a data pulse in the powerline at said one of said signal time positions.