Quantized pulse modulated nonsynchronous clipped speech multi-channel coded communication system

• US 4,070,550 A
• Filed: 06/28/1961
• Issued: 01/24/1978
• Est. Priority Date: 06/28/1961
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Waterbury, John A., Dyer, William W., Carlson, Wayland A., Miller, Ralph H. Jr., Eastman, Richard O.
• Primary Examiner(s): Birmiel, Howard A.
• Application Number:
  US04/122,056
• Time in Patent Office: 6,054 Days
• Field of Search: 325/38-40, 179/15 BA
• US Class Current: 370/204
• CPC Class Codes: H04J 3/1676 Time-division multiplex with pulse-position, pulse-interval, or pulse-width modulation
• CPC Class Codes: H04L 25/493 by transition coding, i.e. the time-position or direction of a transition being encoded before transmission

Abstract

1. A quantized pulse-modulated nonsynchronous clipped speech multi-channeloded communication system comprising transmitter terminals and receiver terminals; said transmitter terminals comprising a plurality of channel units, a timing unit, and a transmitting unit; said channel unit including processing section, encoding section and pulse position modulating section; said processing section including input means for coupling a composite waveform thereto, pre-emphasis means operatively receiving said composite waveform for accentuating crossover points in the composite waveform, clipping means operatively receiving the output of said pre-emphasis means for infinitely clipping the amplitude portion of said composite waveform and retaining the frequency information therein, pulse generating means operatively coupled to the output of said clipping means for generating pulses corresponding to said crossover points; gate generator means contained within said encoding section and operatively coupled to the output of said pulse generating means for generating gate pulses; buffer circuit means contained within said timing unit operatively connected to the output of said gate generator means for isolating the outputs of said plurality of channel units, sampling means for sampling the outputs of said channel units fed to said buffer circuit means, first coincidence circuit means operatively receiving the output of said buffer circuit means and said sampling means for generating an output pulse when pulses from said summing circuit and said sampling means are coincident therein, channel coding means comprising a delay line operatively receiving pulses from said coincidence circuit means for generating start stop and a plurality of channel pulses corresponding to the number of channel units; second coincidence circuit means operatively receiving pulses from said gate generating means and pulses from said delay line corresponding to the appropriate channel unit for generating an output pulse when pulses from said gate generator and said delay line are coincident therein, blocking oscillator means operatively receiving pulses from the output of said second coincidence circuit means for generating first output pulse which is operatively coupled to said gate generator means for turning off said gate generating means and generating a second pulse; comparator means in said pulse position modulator section and operatively receiving the second output pulse from said blocking oscillator and receiving a signal corresponding to said composite waveform and time modulating said second output pulse from said blocking oscillator wherein the modulation corresponds to the amplitude information of the input waveform; other buffer circuit means contained within said transmitting unit for receiving start-stop pulses from said delay line and time modulated channel pulses from said comparator means wherein said channel pulses are contained between said start-stop pulses, and propagating means operatively receiving the output trains of pulses from said other buffer circuit means for propagating said trains of pulses; said receiver terminal comprising

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Claims

1. A quantized pulse-modulated nonsynchronous clipped speech multi-channel coded communication system comprising transmitter terminals and receiver terminals;

said transmitter terminals comprising a plurality of channel units, a timing unit, and a transmitting unit;

said channel unit including processing section, encoding section and pulse position modulating section;

said processing section including input means for coupling a composite waveform thereto, preemphasis means operatively receiving said composite waveform for accentuating crossover points in the composite waveform, clipping means operatively receiving the output of said preemphasis means for infinitely clipping the amplitude portion of said composite waveform and retaining the frequency information therein, pulse generating means operatively coupled to the output of said clipping means for generating pulses corresponding to said crossover points;

gate generator means contained within said encoding section and operatively coupled to the output of said pulse generating means for generating gate pulses;

buffer circuit means contained within said timing unit operatively connected to the output of said gate generator means for isolating the outputs of said plurality of channel units, sampling means for sampling the outputs of said channel units fed to said buffer circuit means, first coincidence circuit means operatively receiving the output of said buffer circuit means and said sampling means for generating an output pulse when pulses from said summing circuit and said sampling means are coincident therein, channel coding means comprising a delay line operatively receiving pulses from said coincidence circuit means for generating start stop and a plurality of channel pulses corresponding to the number of channel units;

second coincidence circuit means operatively receiving pulses from said gate generating means and pulses from said delay line corresponding to the appropriate channel unit for generating an output pulse when pulses from said gate generator and said delay line are coincident therein, blocking oscillator means operatively receiving pulses from the output of said second coincidence circuit means for generating first output pulse which is operatively coupled to said gate generator means for turning off said gate generating means and generating a second pulse;

comparator means in said position modulator section and operatively receiving the second output pulse from said blocking oscillator and receiving a signal corresponding to said composite waveform and time modulating said second output pulse from said blocking oscillator wherein the modulation corresponds to the amplitude information of the input waveform;

other buffer circuit means contained within said transmitting unit for receiving start-stop pulses from said delay line and time modulated channel pulses from said comparator means wherein said channel pulses are contained between said start-stop pulses, and propagating means operatively receiving the output trains of pulses from said other buffer circuit means for propagating said trains of pulses;

said receiver terminal comprising a receiver unit for receiving and detecting trains of pulses;

master decoder means operatively receiving trains of pulses from said receiver unit for separating incoming trains of pulses into channels and for generating a time reference pulse;

at least one channel decoder means including coincidence means operatively receiving pulses from said master decoder means for determining the presence of information on a particular channel by comparing said reference pulse to individual channel pulses in the coincidence means;

at least one reprocessing means operatively receiving pulses from said channel decoder means for converting information applying to a particular channel from pulses to a reproduction of the originating signals;

each reprocessing unit including pulse position demodulator means operatively receiving pulses from said channel decoder means for converting time modulation information to a DC voltage which is proportional to the amplitude information;

a clipped speech section contained within said audio reprocessing means operatively receiving output pulses from said channel decoder means for recovering the frequency information contained therein;

variable amplifier means operatively receiving amplitude information from said pulse position demodulator means and audio frequency information from said clipped speech means for combining said amplitude information and said frequency information thereby improving the naturalness of the output speech and audio output means operatively receiving the output of said variable amplifier means for reproducing said output waveform from said variable amplifier means.

2. A quantized pulse modulated nonsynchronous clipped speech multi-channel coded communications system comprising;

at least one transmitter terminal and receiver terminal;

said transmitter terminal including, audio processing means for receiving a composite waveform and generating output pulses corresponding to zero crossover points in said composite waveform, gate generating means receiving output pulses from said audio processing means;

timing means including, oscillator means for generating output pulses at a desired frequency for sampling the output of said gate generator means, coincidence circuit means receiving pulses from said gate generator means and said oscillator means for generating an output pulse when pulses from said gate generator means and said oscillator means are coincident therein, channel multiplexing means for generating start stop pulses and channel pulses at predetermined time intervals therebetween;

other conicidence circuit means operatively receiving output pulses from said gate generator means and output pulses from said multiplexing means corresponding to a channel for generating an output respective pulses when said pulse are coincident therein, pulse generator means receiving output pulses from said second coincidence circuit means for generating a reset pulse which is operatively coupled to said gate generator means for turning off said gate generator and also generating a second output pulse;

pulse position modulating means including comparator means receiving said second output pulse corresponding to said zero crossover point from said pulse generating means and said composite wave for time modulating said output pulse from said pulse generating means in accordance with amplitude information in said composite waveform;

buffer circuit means receiving said start and stop pulses from said multiplexing means and output pulses from said voltage comparator means so that the output pulses from said voltage comparator means are correctly positioned according to predetermined channels between said start and stop pulses; and

radio frequency transmission means for propagating said start stop and channel pulses;

said receiver terminal comprising a receiver unit for detecting and producing transmitted pulse train configurations;

master decoder means operatively receiving pulse train configurations from said receiver means for separating the incoming pulse train configurations into corresponding channel pulses and for generating a time reference pulse;

channel decoder means operatively receiving said channel pulses and said time reference pulse for determining the presence of information on a particular channel by comparing said reference pulse to individual channel pulses;

reprocessing means corresponding to said channel decoder means including pulse position demodulator means operatively receiving pulses from said channel decoder means for converting the time modulation information to a potential which is proportional to amplitude information;

flip-flop means included in said reprocessing means operatively receiving output pulses from said channel decoder means for recovering amplitude information from said pulses;

integrating means operatively receiving the output of said flip-flop means for generating a potential corresponding to frequency information;

variable amplifier means operatively receiving said potentials corresponding to amplitude and frequency information and combining said information to improve the naturalness of the subsequent output waveform; and

output means operatively receiving the output of said variable amplifier means for reproducing said output waveform.

3. A clipped speech coded pulse communications system comprising transmitter terminals and receiver terminals;

said transmitter terminals comprising a plurality of channel units, a timing unit, and a transmitting unit;

said channel unit including an audio processing section, encoding section and pulse position modulating section;

said audio processing section including input means for coupling a composite waveform thereto, pre-emphasis means for accentuating crossover points present in the composite waveform, clipping means operatively coupled to said pre-emphasis network for infinitely clipping the amplitude portion of said composite waveform and retaining said frequency information contained therein, pulse generating means operatively coupled to the output of said clipping means for generating pulses corresponding to said crossover points;

gate generator means contained within said encoding section and operatively coupled to the output of said pulse generating means for generating gate pulses corresponding to input pulses thereto;

buffer circuit means contained within said timing unit operatively connected to the output of said gate generator means for isolating the outputs of said plurality of channel units, sampling means for sampling the outputs of said channel units to said buffer circuit means, first coincidence circuit means operatively receiving the output of said buffer circuit means and said sampling means for generating an output pulse when pulses from said buffer circuit and said sampling means are coincident therein, channel coding means operatively receiving pulses from said coincident circuit means for generating start stop and a multiplicity of channel pulses contained between said start and stop pulses;

second coincidence circuit means operatively receiving pulses from said gate generating means and pulses from said coding means corresponding to the appropriate channel unit for generating an output pulse when pulses from said gate generator and said coding means are coincident therein, blocking oscillator means included in said pulse position modulating section operatively receiving pulses from the output of said coincidence circuit means for generating a first output pulse which is operatively coupled to said gate generator means for turning off said gate and for generating a second pulse;

comparator means included in said pulse position modulator section operatively receiving output pulses from said second blocking oscillator and receiving a signal corresponding to said composite waveform and time modulating said output pulse from said second blocking oscillator through the use of the amplitude information contained within said composite waveform thereby generating an output pulse from said comparator means which is time modulated corresponding to amplitude information;

other buffer circuit means contained within said transmitting unit for receiving start and stop pulses from said delay line and time modulated channel pulses from said comparator means wherein said channel pulses are contained between said start and stop framing pulses, and propagating means operatively receiving output trains of pulses from said other buffer circuit means for propagating said trains of pulses;

said receiver terminal comprising a receiver unit for receiving and detecting trains of pulses;

master decoder means operatively receiving trains of pulses from said receiver unit for separating the incoming trains of pulses into channels and for generating a time reference pulse;

a multiplicity of channel decoder units operatively receiving pulses from said master decoder means for determining the presence of information on a particular channel by comparing said reference pulse to individual channel pulses in coincidence means contained therein;

a multiplicity of audio reprocessing means corresponding in number to said channel decoder means for converting information applying to a particular channel from pulses to a reproduction of the originating signals;

each said audio reprocessing unit including pulse position demodulator means operatively receiving pulses from said channel decoder means for converting said time modulation information to a DC voltage which is proportional to speech amplitude information;

a clipped speech section contained within said audio reprocessing means operatively receiving output pulses from said channel decoder means for recovering the infinitely clipped speech information from the time modulated pulses corresponding to the frequency information therein;

variable amplifier means operatively receiving audio amplitude information from said pulse position demodulator means and audio frequency information from said clipped speech means for combining said amplitude information and said frequency information thereby improving the naturalness of the output speech, and audio output means operatively receiving the output of said variable amplifier means for reproducing said output waveform.

4. A quantized pulse modulated nonsynchronous clipped speech multi-channel coded communications system comprising;

at least one transmitter terminal and receiver terminal;

said transmitter terminal including, audio processing means for receiving a composite waveform and generating output pulses corresponding to crossover points in said composite waveform, gate generating means receiving output pulses from audio processing means and generating gate pulses corresponding to said crossover points;

timing unit means including, sampling means for sampling the output of said gate generator means, coincidence circuit means receiving pulses from said gate generator means and said sampling means and generating an output pulse when pulses from said gate generator means and said sampling means are coincident therein, channel multiplexing means for generating start and stop pulses and channel pulses at predetermined time intervals therebetween;

second coincidence circuit means operatively receiving output pulses from said gate generator means and output pulses from said multiplexing means corresponding to a desired channel for generating an output pulse when said pulses are coincident therein, pulse generator means receiving output pulses from said second coincident circuit means for generating a reset pulse which is operatively coupled to said gate generator means for turning off said gate generator and also generating an output;

pulse position modulating means receiving output pulses from said pulse generating means and a signal corresponding to said original composite wave for time modulating said output pulses from said pulse generating means in accordance with amplitude information in said signal;

buffer circuit means receiving start and stop pulses from said multiplexing means and output pulses from said pulse position modulating means so that the output pulses from said voltage comparator means are correctly positioned between said start and stop pulses; and

radio frequency transmission means for propagating said trains of pulses;

said receiver terminal comprising a receiver unit for detecting said transmitted pulse train configurations;

master decoder means operatively receiving pulse train configurations from said receiver means for separating incoming pulse train configurations into corresponding channels and for generating a time reference pulse channel decoder means for determining the presence of information on a particular channel by comparing said reference pulse to individual channel pulses;

audio reprocessing means corresponding to said channel decoder means including pulse position demodulator means receiving output pulses from said channel decoder means for converting said pulse position modulation information to a DC potential which is proportional to speech amplitude information, clipped speech means included in said audio reprocessing means for recovering the speech information from pulses received from said channel decoder means, amplifier mixing means receiving the output of said pulse position demodulator means corresponding to audio amplitude information and the output of said clipped speech means corresponding to audio frequency information for mixing said outputs therein thereby combining said frequency information and said amplitude information in a form suitable for reproduction.

5. A quantized pulse-modulated nonsynchronous clipped speech multi-channel transmitter terminal comprising;

at least one input means for coupling a composite waveform thereto;

pulse generating means for generating pulses at zero crossover points in said composite waveform;

gate generator means operatively receiving the output pulses from said pulse generating means for generating gate pulses;

channel coding means including, sampling means for sampling the output of said gate generator at a predetermined rate, coincidence circuit means operatively receiving output pulses from said gate generator means and said sampling means for generating an output pulse when a sampling and gate pulse are coincident therein, delay means in said channel coding means operatively receiving output pulses from said first coincidence circuit means for generating start stop and channel pulses therebetween;

second coincidence circuit means operatively receiving pulses from said gate generator means and an appropriate channel pulse from said delay means for generating an output pulse when said gate generator pulse and channel pulse is coincident therein;

pulse modulator means operatively coupled to said input means operatively receiving output pulses from said second coincidence circuit means and said composite waveform for time modulating said pulses from said second coincidence circuit means in accordance with the amplitude of the composite waveform at that time so constructed and arranged that the sampling of said composite waveform occurs at a predetermined time after the output pulse from second coincidence circuit means corresponding to the zero crossover point in said composite waveform is present in said pulse modulator means; and

transmitter means operatively receiving modulated pulses from said pulse modulator means including multiplexing means for inserting said modulated pulses in their proper channel position between said start and stop pulses, and propagating means operatively receiving the output of said multiplexing means for propagating trains of pulses comprising start stop and channel pulses contained therebetween.

6. A quantized pulse modulated nonsynchronous clipped speech multi-channel coded transmitter terminal comprising;

input means for coupling a composite waveform thereto;

clipping means operatively receiving said composite waveform for infinitely clipping the amplitude portion thereof and retaining frequency information therein;

pulse generating means operatively receiving the output of said clipper means for generating pulses at zero crossover points in said infinitely clipped waveform;

sampling means operatively receiving the output of said pulse generating means for sampling said output at a predetermined frequency;

pulse position modulator means operatively receiving the output pulses corresponding to said zero crossover points and said original composite waveform for time modulating said output pulses in accordance with amplitude information in said composite waveform thereby effectively amplitude sampling said original composite waveform at a frequency determined by the sampling of the output pulses corresponding to zero crossover points;

channel timing means operatively receiving said sampled output pulses for generating start and stop pulses;

transmitter means operatively receiving said start and stop pulses and said time modulated pulses so constructed and arranged that said time modulated channel pulses are inserted between said start and stop pulses.

7. A pulse modulated nonsynchronous clipped speech channel coded communications receiver comprising;

a receiver unit for amplifying and detecting trains of pulses containing start stop and channel pulses contained between said start and stop pulses;

a master decoder unit operatively receiving output trains of pulses from said receiver unit for separating the incoming trains of pulses into appropriate channel pulse and for generating a time reference pulse;

at least one channel decoder unit operatively receiving said channel reference pulse and said time reference pulse so constructed and arranged that said channel reference pulse activates said channel decoder unit when information is present on a channel;

at least one audio reprocessing unit including pulse position demodulator means for reclaiming amplitude information contained in said time modulated channel pulse and frequency information recovering means;

said pulse position demodulator means operatively receiving time modulated pulse units corresponding to said channel pulse for generating a DC voltage which is proportional to the speech amplitude information contained therein;

said frequency information recovery means operatively receiving channel pulses for recovering the speech information from the time modulated pulses corresponding to said channel pulses and producing an output potential corresponding to said frequency information; and

audio amplifier means operatively receiving said DC potential corresponding to amplitude information and said potential corresponding to audio frequency information for combining the two potentials in such a manner that substantial duplicate of the original composite waveform is reproduced therein.

8. A pulse modulated nonsynchronous clipped speech multi-channel coded communications receiver terminal comprising;

detecting and reproducing means for receiving an original transmitted pulse train configuration wherein said configuration comprises start and stop pulses and time modulated channel pulses contained therebetween;

decoder means operatively receiving output pulse train configurations from said detecting and reproducing means for separating said incoming pulse train configurations into channel pulses;

at least one channel coincidence means operatively coupled to said decoder means for determining when a channel is present therein and generating an output pulse when a channel is present therein;

amplitude information recovery means operatively receiving output pulses from said coincidence means for generating a DC voltage which is proportional to the time modulation of said channel pulse;

frequency information recovery means operatively coupled to said channel coincident means for receiving output pulses therefrom and generating a DC potential which is proportional to frequency information contained therein and mixing means operatively receiving said DC voltage corresponding to amplitude information and said potential corresponding to frequency information for combining said outputs corresponding to frequency information and amplitude information generating an output composite waveform which is a substantial duplicate of an original composite waveform.

9. A quantized pulse-modulated nonsynchronous clipped speech multi-channel coded discrete address communications network comprising, at least one transmitter terminal and at least one receiver terminal;

said transmitter terminal comprising at least one input terminal for coupling a composite waveform thereto;

pulse generating means operatively receiving pulses from said input terminal for generating output pulses at the zero crossover points of said input waveform;

sampling means operatively connected to said pulse generator means for sampling said output pulses at a predetermined rate;

timing means operatively receiving output pulses from said sampling means corresponding to said sampled output for generating start stop and at least one address pulse therebetween;

pulse position modulator means operatively receiving said address pulse from said timing means for position modulating said pulse in accordance with amplitude information in said input waveform and wherein said address pulse determines the optimum sampling point at which the input waveform is amplitude sampled;

multiplexing means operatively coupled to said timing means and to said pulse position modulator means for receiving start stop and modulated address pulses from said respective units and inserting said address pulses into proper position between said start stop pulses;

transmitter means operatively receiving said trains of start stop and address pulses for transmitting said start stop and address pulses;

said receiver terminal comprising means for receiving and detecting said trains of start stop and address pulses;

master decoder means operatively coupled to said receiving and detecting means and including coincidence means for determining when a train of start stop and address pulses therebetween contains the address pulse corresponding to the address of the said receiver terminal and for generating an output pulse when the appropriate start stop and address pulse are coincident therein;

pulse position demodulator means operatively receiving time modulated output pulses from said coincidence means for extracting the amplitude information corresponding to said time modulation and producing an output DC level corresponding thereto;

frequency information recovery means operatively receiving said output pulses from said coincidence means for recovering the frequency information contained therein and generating an output level corresponding to the frequency information;

an output mixing means operatively receiving the outputs of said pulse position demodulator means and said frequency information recovery means for mixing said outputs and thereby generating an output composite waveform that approximates an original composite waveform.

10. A quantized pulse-modulated nonsynchronous clipped speech multi-channel coded communications network comprising;

at least one transmitter terminal and at least one receiver terminal;

said transmitter terminal comprising;

at least one input means for coupling a composite waveform thereto;

pulse generating means operatively coupled to said intput means for generating pulses corresponding to zero crossover points in the input composite waveform;

timing means receiving output pulses from said pulse generating means for generating start stop and address pulses;

pulse position modulating means operatively coupled to said timing means and to said input terminal for position time modulating said pulses corresponding to the address pulses by an amount corresponding to the amplitude information in the input composite waveform by said address pulses and wherein said input waveform is amplitude sampled at a time determined and transmitter multiplexing means operatively receiving time modulated pulses and said start and stop pulses for inserting said time modulated pulses at predetermined points between said start and stop pulses so that a predetermined coded train of pulses is generated;

said receiver terminal comprising means for receiving and detecting said coded trains of pulses;

master decoder means operatively receiving said detected trains of pulses comprising coincidence means responsive to the address of said receiver so that when a train of pulses comprising start stop and address pulses is coincident in said coincidence means an output pulse is generated;

pulse position demodulator means operatively coupled to said coincident means and receiving decoded time modulated pulses therefrom for extracting the amplitude information therein and producing an output DC level corresponding to said amplitude information;

frequency information recovery means operatively coupled to said coincidence means and receiving output pulses therefrom for extracting frequency information and producing an output potential corresponding thereto; and

mixing means operatively receiving the output DC level of said pulse position demodulator means and said potential from said frequency information recovery means for mixing said output levels and producing a composite waveform substantially corresponding to an original composite waveform.