Delta modulator for a time division multiplex system

Claim 1

IN A TIME DIVISION MULTIPLEX SYSTEM HAVING A GIVEN FRAME PERIOD, A PLURALITY OF ANALOG SIGNAL SOURCES, TIME MULTIPLEX MEANS FOR SEQUENTIALLY SAMPLING EACH OF SAID SOURCES EACH FRAME PERIOD, FIRST MEANS COUPLED TO SAID TIME MULTIPLEX MEANS, SAID FIRST MEANS INCLUDING DELAY MEANS HAVING A DELAY EQUAL TO ONE FRAME PERIOD FOR SEQUENTIALLY COMPARING THE RELATIVE LEVELS OF THE TIME MULTIPLEXED SAMPLES OF EACH INDIVIDUAL ANALOG SIGNAL APPLIED THERETO DURING SUCCESSIVE FRAMES TO PRODUCE A MOMENTARY OUTPUT SIGNAL HAVING A RESPECTIVE ONE OF FIRST AND SECOND PREDETERMINED VALUES IN ACCORDANCE WITH WHETHER THE LEVEL OF THE SAMPLE OF THAT INDIVIDUAL ANALOG SIGNAL DURING A FRAME IS GREATER OR SMALLER THAN THE LEVEL OF THE SAMPLE OF THAT INDIVIDUAL ANALOG SIGNAL DURING THE PREVIOUS FRAME, SECOND MEANS FOR TRANSMITTING SUCCESSIVE OUTPUT SIGNALS TO A RECEIVING POINT, AND THIRD MEANS INCLUDING DEMULTIPLEXING MEANS AT SAID RECEIVING POINT HAVING SAID SUCCESSIVE OUTPUT SIGNALS APPLIED AS AN INPUT THERETO FOR RECONSTRUCTING SAID ANALOG SIGNALS IN ACCORDANCE WITH THE RESPECTIVE SAID VALUES OF EACH OF SAID SUCCESSIVE OUTPUT SIGNALS.