Time domain radio transmission system

• US 4,813,057 A
• Filed: 02/03/1987
• Issued: 03/14/1989
• Est. Priority Date: 12/03/1984
• Status: Expired due to Term

• Current Assignee: Time Domain Corporation (Humatics Corporation)
• Original Assignee: Charles A. Phillips
• Inventors: Fullerton, Larry W.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Chin, Stephen
• Application Number:
  US07/010,440
• Time in Patent Office: 770 Days
• Field of Search: 375/1, 375/115, 375/37, 375/23, 375/96, 370/10, 370/107, 329/107, 332/9 R, 307/265, 307/271, 380/35
• US Class Current: 375/259
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00
• CPC Class Codes: H04B 1/69 Spread spectrum techniques
• CPC Class Codes: H04B 1/71637 Receiver aspects H04B1/7183 takes precedence
• CPC Class Codes: H04B 1/7174 Pulse generation in general H04L25/03834
• CPC Class Codes: H04B 14/026 using pulse time characteristics modulation, e.g. width, position, interval
• CPC Class Codes: H04L 27/103 Chirp modulation for spread spectrum techniques H04B1/69

Abstract

A time domain communications system wherein time modulated, impulse derived signals are multiplied by a template signal, integrated, and then demodulated. By this process, usable signals are obtained which would be otherwise obscured by noise.

Claims

1. A time domain radio transmission system comprising:

a radio transmitter comprising;

pulse generating means for generating reoccurring pulses units, wherein each pulse unit is comprised of at least one pulse signal,

a source of intelligence signals,

modulation means responsive to said pulse generating means and said source of intelligence signals for providing, as a modulated output, a train of signals wherein at least a discrete edge region of a last-named signal is varied in time position as a function of said intelligence signals,

transmitting antenna means comprising a wide band transmitting antenna,

a D.C. power source, and

power switching means coupled to said wideband transmitting antenna and said power source having a control input responsive to a said modulated output for switching between the states of power applied to said wideband antenna and not being applied to said wideband antenna, whereby discrete switched pulses are transmitted as transmitted signals;

a radio receiver comprising;

receiving means comprising a wide band antenna for receiving transmissions from said transmitting antenna and for providing received signals,

signal generating means responsive to a control signal for generating, repetitively, template signals generally corresponding in time to an average time of occurrence of a said signal portion of a said received signal from a said transmitted signal, and

signal timing means responsive to said received signals and said template signals for generating said control signal; and

demodulation means comprising;

multiplying means responsive to said template signals and said received signals for providing product signals,

signal means including integration means responsive to said product signals for providing an integral signal representative of the integral of said product signal, and

means responsive to said integral signal for reproducing said intelligence signals.

2. A system as set forth in claim 1 wherein said power switching means includes at least one avalanche mode operated transistor having a collector connected to said bias power input and further including a shorted transmission line connected across said switched power output, said shorted transmission line being of an electrical length approximately equal to one-half of a selected pulse width.

3. A system as set forth in claim 1 wherein said signal generating means includes signal controlled oscillating means responsive to a said control signal for maintaining the time position of said template signals independent of modulation.

4. A system as set forth in claim 1 wherein:

said signal portion of a said received signal including a major lobe of one polarity;

said signal timing means includes first and second signal multipliers and means responsive to said received signals for applying as a first input to each of said first and second multipliers said received signals;

said signal generating means includes means for providing a first set of said template signals as a second input to said first multiplier and a second set of said template signals to said second multiplier, and wherein said second set of discrete signals are delayed for a period of substantially one-half the period of said major lobe of said received signals; and

said timing means includes combining means for combining of the outputs of said first and second multipliers for providing said control signals.

5. A system as set forth in claim 4 wherein said combining means is a differential amplifier.

6. A system as set forth in claim 1 wherein;

said demodulation means includes means responsive to the output of said integration means for providing timed output signals indicative of the time of occurrence of said received signal;

said signal generating means includes means for providing reference output signals which are a function of the average time of occurrence of said received signals;

said demodulation means includes pulse width generation means responsive to said timed output signals and said reference output signals for generating rectangular pulses which vary in width as a function of the variation in time of occurrence of said received signals; and

said demodulation means includes low pass filter means responsive to said rectangular pulses for providing a signal output which varies in amplitude as a function of the width of said rectangular pulses.

7. A system as set forth in claim 1 wherein said power switching means is a light responsive switch, and said modulation means includes means for providing as said train of signals a train of pulses of light.

8. A system as set forth in claim 1 wherein said power switching means comprises at least one avalanche mode operated transistor including a collector electrode connected to said bias power input and capacitive means connected between said collector and across the output of said transistor for storing bias power input pending receipt of a said modulated output.