Digital communications system with time-frequency multiplexing

Claim 2

A communication system having a plurality of inputs comprising a plurality of first means sampling the change in signals at respective inputs simultaneously in repetitive intervals and producing for each input first pulses representing signal change and second pulses representing direction of change between successive intervals, second means coupled to the output of said first means for combining pulses from a plurality of inputs to form binary words, said second means including means registering and reading out said first pulses as said binary words to increase the readout time compared to sampling interval, an address assignment matrix wired to receive said binary words, and output means connected to said matrix for transmitting predetermined frequency bursts of energy at particular times as determined by said matrix as signals to a transmission medium that are decipherable into original input signals.

Claim 3

The system of claim 1 further defined by the means sampling input signals producing bipolar pulses of fixed amplitude, means converting said bipolar pulses to unipolar pulses and generating said second pulses from said bipolar pulses as unipolar polarity pulses, said means combining pulses including logic circuitry producing the equivalent of a different word for each combination of unipolar pulses, and means coding said polarity pulses for transmission.

Claim 4

The system of claim 1 further defined by said output means including means generating a plurality of fixed frequencies connected to the output of said address assignment matrix for producing for transmission frequency bursts for fixed times at particular times as determined by matrix energization.

Claim 5

The system of claim 3 further defined by frequency sensing means connected to the transmission medium of the system and controlling said means generating a plurality of fixed frequencies for disabling the generation of a frequency at the time it is already present on the transmission medium.

Claim 6

An improved communication system comprising a transmitter connected to user inputs and including sampling means generating a fixed amplitude unipolar information pulse for each input variation in excess of a predetermined minimum during successive sampling periods of a sampling frame and polarity pulses identifying the direction of change of input during each sampling period, logic circuitry connected to receive information pulses from groups of inputs for each sampling period and producing an output pulse on a separate line for each combination of pulses and absences of pulses of each group of inputs for each sampling period, an address assignment matrix connected to receive timing signals and connected to the separate output lines of said logic circuitry and producing matrix output signals, means coding said polarity pulses, and means generating a plurality of fixed frequencies connected to said matrix output signals and coded polarity pulses for producing particular frequency bursts at particular times as transmission addresses at a transmitter output; a transmission medium connected to the output of said means generating a plurality of fixed frequencies; and a receiver having an input connected to said transmission medium and outputs connected to user outlets and including an address decoder matrix coupled to the receiver input and connected to decoding circuitry for reconstrUcting original user inputs and applying same to selected user outlets.

Claim 7

An improved communication system comprising a transmitter connected to user inputs and including sampling means generating a fixed amplitude unipolar information pulse for each input variation in excess of a predetermined minimum during successive sampling periods of a sampling frame and polarity pulses identifying the direction of change of input during each sampling period, logic circuitry connected to receive information pulses from groups of inputs for each sampling period and producing an output pulse on a separate line for each combination of pulses and absences of pulses of each group of inputs for each sampling period, an address assignment matrix connected to receive timing signals and connected to the separate output lines of said logic circuitry and producing matrix output signals, means coding said polarity pulses, and means generating a plurality of fixed frequencies connected to said matrix output signals and coded polarity pulses for producing particular frequency bursts at particular times as transmission addresses at a transmitter output; a transmission medium connected to the output of said means generating a plurality of fixed frequencies; and a receiver having an input connected to said transmission medium and outputs connected to user outlets and including an address decoder matrix coupled to the receiver input and connected to decoding circuitry for reconstrUcting original user inputs and applying same to selected user outlets.

Claim 8

The system of claim 5 further defined by said transmitter including means generating matrix timing pulses applied to the matrix whereby signals to said means generating different frequencies occur at times determined by concurrence of logic circuitry outputs and timing pulses at said matrix.

Claim 9

The system of claim 5 further defined by said sampling periods comprising a plurality of successive short time periods in successive time frames with each time frame defining the time duration of all time slots in said address assignment matrix, and each of said logic circuitry outputs persisting for a complete time frame whereby the binary words are time-frequency coded in said matrix.

Claim 10

The system of claim 5 further defined by said sampling means including means generating one bipolar pulse for a variation of each user input by more than a predetermined amount from one sampling period to the next with the pulse polarity being determined by the direction of change in amplitude of user input, a first trigger means producing first unipolar pulses from said bipolar pulses and second trigger means producing second unipolar pulses from said bipolar pulses identifying the original polarity of said first unipolar pulses, means applying said first pulses to said logic circuitry for production of said outputs and means applying said second unipolar pulses to said matrix for coding and transmission to said receiver.

Claim 11

The system of claim 5 further defined by the logic circuitry of said transmitter being connected to groups of two of the sampling means for producing two-bit binary words for each sampling period, each group of said circuitry including four storage and readout registers with each having paired flip-flop circuits alternately operable by connection to a sampling frame timing pulse source for producing from only one register per sampling frame an output pulse lasting the duration of the frame and applied to a unique line of said matrix.

Claim 12

The system of claim 5 further defined by said receiver having at the input thereof a plurality of band-pass filters separately passing the frequencies of said fixed frequencies for energizing separate lines of the receiver matrix.

Claim 13

The system of claim 5 further defined by a separate delta modulator coupled to each user input through a band limiting filter and receiving timed sampling pulses for producing said information pulses and polarity pulses, a plurality of AND circuits for each delta modulator with one input of each AND circuit connected to the information output of said delta modulator and another input of each AND circuit connected to receive a separate sampling pulse whereby said AND circuits produce pulses representing information pulses in separate sampling periods, said logic circuitry generating a pulse on a separate line for each possible combination of pulses and absence of pulses of each group of inputs for each sampling period, a storage and readout register connected in each of said separate lines and connected to receive a pulse at the beginning of each sampling frame for storing a received pulse and reading out such pulse for the next complete sampling frame, and matrix lines connected one to each register readout for energization for a complete sampling frame for each received pulse.

Claim 14

The system of claim 11 further defined by means applying sampling pulses to said matrix for producing signals from predetermined combinations of register readouts and times for operating said means generating fixed frequencies.

Claim 15

A transmitter for a communication system having a plurality of input terminals adapted to receive band width limited user inputs and a single output terminal adapted for connection to a transmission medium comprising a plurality of delta modulators connected one to each input terminal and receiving sampling pulses defining sampling periods and having a repetition rate in excess of twice the maximum input frequency for producing information pulses identifying input amplitude change in excess of a predetermined minimum between successive sampling pulses and producing polarity pulses identifying the direction of such change to thus digitalize the inputs, means connected to the outputs of each of said delta modulators and to said sampling pulses for producing a pulse in a separate line for each information pulse in a separate sampling period of a plurality of periods comprising a time frame, means combining groups of said separate lines including logic circuitry producing an output on separate buses for each combination of states on the combined lines for each sampling period in said time frame, storage and readout means connected in each of said buses for extending a signal therein for a complete time frame, an address assignment matrix having rows connected to receive matrix time signals comprising a time frame and columns connected to said storage and readout means with output lines energized by matrix concurrence of predetermined matrix time signals and bus energization as unique address signals, and means generating a plurality of different fixed frequencies connected to matrix output lines for generating frequency bursts at particular times as addressed information applied to said output terminal.

Claim 16

A transmitter for a communication system having a plurality of input terminals adapted to receive band width limited user inputs and a single output terminal adapted for connection to a transmission medium comprising a plurality of delta modulators connected one to each input terminal and receiving sampling pulses defining sampling periods and having a repetition rate in excess of twice the maximum input frequency for producing information pulses identifying input amplitude change in excess of a predetermined minimum between successive sampling pulses and producing polarity pulses identifying the direction of such change to thus digitalize the inputs, means connected to the outputs of each of said delta modulators and to said sampling pulses for producing a pulse in a separate line for each information pulse in a separate sampling period of a plurality of periods comprising a time frame, means combining groups of said separate lines including logic circuitry producing an output on separate buses for each combination of states on the combined lines for each sampling period in said time frame, storage and readout means connected in each of said buses for extending a signal therein for a complete time frame, an address assignment matrix having rows connected to receive matrix time signals comprising a time frame and columns connected to said storage and readout means with output lines energized by matrix concurrence of predetermined matrix time signals and bus energization as unique address signals, and means generating a plurality of different fixed frequencies connected to matrix output lines for generating frequency bursts at particular times as addressed information applied to said output terminal.