Method and apparatus for transmitting analog data embedded in a digital pulse train

The method according to claim further including a method of transmitting an analog signal from a different transmitter of said plurality over the same two-wire pair transmission line, comprising;

• transmitting a first sync pulse having a second selected amplitude and a selected width, said second selected amplitude identifying data as being sent by a different particular set of transmitters within said plurality of transmitters, said second selected amplitudes being different from said selected amplitude;
• transmitting a second data pulse after said first sync pulse of said second selected amplitude, said second data pulse having said first amplitude;
• transmitting a second sync pulse after said second data pulse, said second sync pulse having said second selected amplitude;
• transmitting a second data pulse after said second sync pulse, said second data pulse having said first amplitude;
• transmitting a third sync pulse having said second selected amplitude;
• and
• transmitting a third data pulse after said third sync pulse, said third data pulse having said first amplitude.

A circuit for transmitting a signal on a two-wire transmission line from one of a plurality of transmitters coupled to said transmission line, comprising:

• an integrator;
• a multiplexer having an output coupled to said integrator;
• an analog signal source coupled to the input of said multiplexer;
• and
• a switching means for placing a signal on said two-wire transmission line, said switching means being coupled to the output of said integrator, said switching means placing a sync pulse having a selected amplitude on said two-wire transmission line when the charge on said integrator exceeds a high threshold value or is less than a low threshold value and placing a data pulse having a first amplitude different from said selected amplitude on said two-wire transmission line when the charge on said integrator exceeds said low threshold value but is less than said high threshold value, said selected amplitude identifying said signal as being generated by a select set of transmitters coupled to said transmission line.

A method of encoding analog data, comprising:

• a. generating an initial sync pulse having a selected amplitude and a selected width, the initial sync pulse indicating the beginning of an encoding cycle;
• b. generating a data pulse immediately following the generation of the initial sync pulse, the data pulse having a first amplitude, and a width proportional to the value of the encoded data, the encoded data being transmitted on a two-wire transmission line having a plurality of analog data signals from different sources on said two-wire transmission line, and the amplitude of said sync pulse uniquely identifying a source of said data;
• c. generating a sync pulse immediately following the generation of said data pulse, the ending of said initial sync pulse and the beginning of the next sync pulse defining the width of said analog data pulse;
• and
• d. repeating steps b and c until said next sync pulse is an initial sync pulse indicating the beginning of a different encoding cycle.

A method of encoding analog data on a two-wire transmission line having a plurality of transmitters coupled to said two-wire transmission line, comprising the steps of:

• transmitting a first sync pulse having a selected amplitude and a selected width, said selected amplitude identifying data as being sent by a particular set of transmitters within said plurality of transmitters;
• transmitting a second sync pulse having a second selected amplitude and a second selected width, said second selected amplitude identifying data as being sent by a different particular set of transmitters within said plurality of transmitters from that identified by said first sync pulse, said second selected amplitude being different from said selected amplitude;
• transmitting a data pulse after said first sync pulse, said first data pulse having a first amplitude that is different from said selected amplitude and a width corresponding to the value of said encoded analog data;
• transmitting a second data pulse after said second sync pulse of said second selected amplitude, said second data pulse having said first amplitude;
• transmitting a first data separator pulse after said first data pulse, said first data separator pulse having said selected amplitude, the start of said first data separator pulse defining the end of said data pulse;
• and
• transmitting a second data separator pulse after said second data pulse, said second data separator pulse having said second amplitude, the start of said second data separator pulse defining the end of said second data pulse.

A circuit for transmitting encoded data on a two-wire transmission line from a plurality of transmitters coupled to said two-wire transmission line, comprising:

• a first sync pulse generating circuit means for generating a first sync pulse having a first amplitude and a selected width, the sync pulse indicating the beginning of an encoding cycle for a first transmitter coupled to said two-wire transmission line;
• first data pulse generating means for generating a plurality of first data pulses following the generation of said sync pulse, said first data pulse having a selected amplitude, different from said sync pulse amplitude and a width corresponding to the analog value of first encoded data;
• second sync pulse generating circuit means for generating a second sync pulse having a second amplitude different from said first amplitude, said second sync pulse indicating the beginning of an encoding cycle for a second transmitter coupled to said two-wire transmission line;
• second data pulse generating means for generating a plurality of second data pulses following the generation of said second sync pulse, said second data pulse having a selected amplitude and a width proportional to the analog value of second encoded data;
• first separator pulse circuit means for generating first separator pulses between said first data pulses and first separator pulses having said first amplitude;
• and
• second separator pulse circuit means for generating second separator pulses between said second data pulses, said second separator pulses having said second amplitude.