Burst-mode digital transmitter

A communication system for transmitting and receiving optical signals over a communications medium, the communications system comprising:

• subscriber equipment for transmitting reverse electrical signals;
• a plurality of optical transmitters coupled to at least one of the subscriber equipment for converting the reverse electrical signals into reverse digital optical signals having a predetermined wavelength, wherein each of the plurality of optical transmitters comprising:
• a converter for converting the reverse analog electrical signal to a reverse digital optical signal;
• a carrier-detect circuit coupled to monitor reverse analog electrical signals at the input of the converter;
• a delay circuit for preventing loss of information in the reverse signal due to the carrier-detect circuit;
• and
• a switch, coupled to the delay circuit, the carrier-detect circuit controlling the switch, in response to the carrier-detect circuit detecting the presence of a reverse carrier signal in the reverse analog electrical signals, to allow the respective optical transmitter to transmit the reverse digital optical signal upstream through a digital network only when the carrier detect circuit detects the presence of the reverse carrier signal;
• the digital network, coupled to each of the plurality of transmitters, for passively combining the reverse digital optical signals;
• a receiver coupled to the digital network for converting the reverse digital optical signals back to the original reverse signals;
• and
• a headend coupled to the receiver for processing the reverse signals.

A method for conducting reverse communications in a subscriber television system, comprising:

• receiving at an optical transmitter reverse analog electrical signals from a plurality of subscriber equipment;
• converting the reverse analog electrical signals to reverse digital electrical signals;
• delaying the reverse digital electrical signal signals;
• transmitting the reverse digital electrical signals as digital reverse optical signals upstream to a digital network only when the presence of a reverse carrier signal is detected by a carrier-detect circuit;
• passively combining a plurality of the reverse digital electrical signals as digital reverse optical signals received from a plurality of optical transmitters at a digital network;
• and
• converting at a receiver the plurality of reverse digital optical signals back to a plurality of the reverse analog electrical signals.