Transmission of electronic information by pulse position modulation utilizing low average power

• US 5,586,145 A
• Filed: 11/10/1994
• Issued: 12/17/1996
• Est. Priority Date: 01/11/1993
• Status: Expired due to Fees

• Current Assignee: Harry C. Morgan, William H. Boyd
• Original Assignee: Harry C. Morgan, William H. Boyd
• Inventors: Morgan, Harry C., Boyd, William H.
• Primary Examiner(s): Tse, Young T.
• Assistant Examiner(s): Webster, Bryan E.
• Application Number:
  US08/337,045
• Time in Patent Office: 768 Days
• Field of Search: 375/239, 375/237, 375/238, 375/219, 375/257, 375/258, 375/287, 375/288, 375/296, 375/297, 375/317, 375/318, 375/319, 370/8, 370/9, 370/10, 329/311, 329/312, 329/313, 332/112, 332/113, 332/114, 326/62.68, 327/31-38
• US Class Current: 375/239
• CPC Class Codes: H03K 11/00 Transforming types of modulations, e.g. position-modulated pulses into duration-modulated pulses
• CPC Class Codes: H03K 7/04 Position modulation, i.e. PPM
• CPC Class Codes: H03K 9/04 of position-modulated pulses
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/24 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

A method and apparatus are shown for generating and transmitting very short and widely separated high frequency sine-wave pulses of electromagnetic energy into space. A transistor, a charging capacitor, and an inductor are coupled into a first series loop path to form a discharge circuit. A bias voltage source, the same charging capacitor, and a charging resistor are coupled into a second series loop path to form a recharging circuit. The bias voltage source is selected to be capable of biasing the forward conduction path of the transistor near its breakdown condition. An original information signal is sampled upon each occurrence of a periodic reference signal, and the transistor is then triggered into its breakdown or avalanche mode. The starting times of successive transmitted pulses are modified in accordance with a pulse position modulation protocol.

Claims

1. An electrical circuit for generating intermittent high frequency pulses of extremely brief duration, comprising:

(a) a transistor having a base, emitter, and collector;

(b) an inductor connected to the emitter of said transistor;

(c) a charging capacitor coupled between said inductor and the collector of said transistor to form a series loop circuit with the emitter-collector conduction path of said transistor;

(d) a source of bias voltage;

(e) a charging resistor connected between said bias voltage source and the collector of said transistor, for biasing said transistor near its avalanche breakdown voltage as well as supplying a charge to be stored on said charging capacitor that may be discharged through said transistor;

(f) a bias resistor connected between the base of said transistor and one end of said inductor;

(g) a coupling capacitor coupled to the base of said transistor for applying intermittent triggering pulses thereto to produce an avalanche of current from said charging capacitor through said transistor in response to each said triggering pulse;

(h) said charging resistor being selected of sufficiently large value to permit the recharging of said charging capacitor at only a slow rate so that the avalanche current discharged through said transistor in response to each pulse is essentially limited to the charge previously stored on said charging capacitor; and

(i) the capacity of said charging capacitor, the maximum voltage applied to said charging capacitor, and the time interval between successive triggering pulses, being such as to avoid destruction of said transistor.

2. An electrical circuit as in claim 1 wherein said transistor is of the N-P-N type.

3. An electrical circuit as in claim 1 which includes a delay line forming said charging capacitor.

4. An electrical circuit as in claim 3 wherein said delay line is a coaxial cable.

5. An electrical circuit as in claim 1 which further includes an antenna coupled in parallel with said inductor.

6. Art electrical circuit for generating intermittent high frequency pulses of extremely brief duration, comprising:

(a) a transistor having a base, emitter, and collector;

(b) an inductor having one end connected to the base of said transistor;

(c) a first resistor connected between the other end of said inductor and ground;

(d) a charging capacitor coupled between ground and the collector of said transistor to form a series loop circuit with the base-collector conduction path of said transistor;

(e) a source of bias voltage;

(f) a charging resistor connected between said bias voltage source and the collector of said transistor, for biasing said transistor near its avalanche breakdown voltage as well as supplying a charge to said charging capacitor that may be discharged through said transistor;

(g) a bias resistor connected between the emitter of said transistor and the other end of said inductor;

(h) a coupling capacitor coupled to the emitter of said transistor for applying intermittent triggering pulses thereto to produce an avalanche of current from said charging capacitor through said transistor in response to each said triggering pulse;

(i) said charging resistor being selected of sufficiently large value to permit the recharging of said charging capacitor at only a slow rate so that the avalanche current discharged through said transistor in response to each pulse is essentially limited to the charge previously stored on said charging capacitor; and

(j) the capacity of said charging capacitor, the maximum voltage applied to said charging capacitor, and the time interval between successive triggering pulses, being such as to avoid destruction of said transistor.

7. An electrical circuit as in claim 6 wherein said transistor is of the N-P-N type.

8. An electrical circuit as in claim 6 which includes a delay line forming said charging capacitor.

9. An electrical circuit as in claim 8 wherein said delay line is a coaxial cable.

10. An electrical circuit as in claim 6 which further includes an antenna coupled in parallel with said inductor.

11. An electrical circuit for producing short, widely separated, high frequency pulses, comprising:

(a) a transistor having a base, a collector, and an emitter, and having a forward conduction path extending from its collector to one of said base and emitter;

(b) an inductor;

(c) a delay line connected in a series loop circuit with said inductor and with said forward conduction path of said transistor;

(d) circuit means for charging said delay line and holding said forward conduction path of said transistor near its breakdown condition; and

(e) means for intermittently triggering said transistor into its breakdown condition,

so that an avalanche of current then flows from said delay line through said forward conduction path into said inductor, and there appears across said inductor essentially a single sine wave cycle of voltage representing an oscillation frequency that is determined essentially by inductance value of said inductor and resistance value of said forward conduction path during conduction.

12. An electrical circuit as claimed in claim 11 wherein said forward conduction path is the collector-emitter path.

13. An electrical circuit as claimed in claim 11 wherein said forward conduction path is the collector-base path.

21. An electrical circuit as in claim 11 wherein said triggering means is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

22. An electrical circuit as in claim 11 wherein said triggering means is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

14. An electrical circuit for generating intermittent high frequency pulses of extremely brief duration, comprising:

(a) a transistor having a base, a collector, and an emitter, and a forward conduction path from its collector through one of said base and emitter;

(b) an inductor connected in series with said forward conduction path of said transistor;

(c) voltage means for placing said forward conduction path of said transistor near its breakdown condition;

(d) triggering means for actuating said transistor so that said forward conduction path breaks down at least momentarily and conducts in the avalanche mode; and

(e) means associated with said voltage means for supplying a large current to said forward conduction path of said transistor during its breakdown mode, whereby said inductor produces essentially a single sine wave cycle of voltage representing an oscillation frequency determined essentially by the ratio of the inductance of said inductor to the resistance of said forward conduction path.

15. An electrical circuit as claimed in claim 14 wherein said forward conduction path is the collector-emitter path.

23. An electrical circuit as in claim 14 wherein said triggering means is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

24. An electrical circuit as in claim 14 wherein said triggering means is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

16. An electrical circuit for generating intermittent high frequency pulses of extremely brief duration, comprising:

(a) a transistor;

(b) circuit means biasing said transistor near its avalanche breakdown voltage;

(c) an inductor and a capacitor coupled in a series loop circuit with the emitter-collector conduction path of said transistor;

(d) a charging circuit for supplying a charge to said capacitor so that said capacitor will hold a charge ready to be discharged through said avalanche transistor;

(e) means for applying intermittent triggering pulses to said transistor to produce avalanche conduction therethrough in response to each said triggering pulse;

(f) said charging circuit also being adapted to re-charge said charging capacitor at a slow rate so that an avalanche current is discharged through said transistor which is essentially limited to the charge previously stored on said charging capacitor;

(g) a transmitting antenna coupled in parallel with said inductor; and

(h) the capacity of said charging capacitor, the maximum voltage applied to said charging capacitor, and the time interval between successive triggering pulses, being such as to avoid destruction of said transistor.

17. An electrical circuit as in claim 16 wherein said means for applying triggering pulses is adapted to apply said pulses to the base of said transistor.

18. An electrical circuit as in claim 16 which includes a delay line forming said charging capacitor.

19. An electrical circuit as in claim 18 wherein said delay line is a coaxial cable.

25. An electrical circuit as in claim 16 wherein said triggering means is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

26. An electrical circuit as in claim 16 wherein said triggering means is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

20. An electrical circuit for generating intermittent high frequency pulses of extremely brief duration and providing them to a twisted pair transmission line, comprising:

(a) a transistor having a base, a collector, and an emitter, and a forward conduction path from its collector through one of said base and emitter;

(b) a resistor and a twisted pair transmission line connected in a series loop circuit with said forward conduction path of said transistor;

(c) voltage means for placing said forward conduction path of said transistor near its breakdown condition;

(d) triggering means for actuating said transistor so that said forward conduction path breaks down at least momentarily and conducts in the avalanche mode; and

(e) delay line means associated with said voltage means for supplying a large current to said forward conduction path of said transistor during its breakdown mode, whereby said resistor produces a voltage wave that is applied through said resistor to said twisted pair transmission line.

27. An electrical circuit as in claim 20 wherein said triggering means is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

28. An electrical circuit as in claim 20 wherein said triggering means is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

29. An electrical circuit utilizing a transistor in the avalanche mode for generating and transmitting very short and widely separated high frequency sine-wave pulses of electrical energy, comprising:

a discharge circuit including a charging capacitor and an inductor connected in a first series loop path with two electrodes of the transistor that are part of a forward conduction path;

a triggering circuit including a coupling capacitor connected to the other electrode of the transistor to provide an input for triggering it into its breakdown or avalanche mode;

antenna means coupled to said inductor for transmitting electromagnetic energy into space;

a recharging circuit including a charging resistor and a bias voltage source coupled with said charging capacitor into a second series loop path, said bias voltage source being capable of biasing the forward conduction path of the transistor near its breakdown condition; and

the time constant of said recharging circuit being at least many times greater than the time constant of said discharge circuit, so that when current is being discharged from said capacitor into said inductor through said forward conduction path of said transistor the avalanche mode current carriers will recombine concurrently with or soon after the generation of the RF cycle or cycles, and then end the low resistance avalanche mode.

30. An electrical circuit as in claim 29 wherein said charging resistor is selected of sufficiently large value to permit the recharging of said charging capacitor at such a slow rate that the avalanche current discharged through said transistor in response to each pulse is essentially limited to the charge previously stored on said charging capacitor.

31. An electrical circuit as in claim 29 wherein the capacity of said charging capacitor, the maximum voltage applied to it, and the time interval between successive triggering pulses, are so selected as to avoid destruction of said transistor.

32. An electrical circuit as claimed in claim 29 wherein said transistor is of the N-P-N type having a base, a collector, and emitter, and a forward conduction path extending from its collector to one of said base and emitter;

one terminal of said bias voltage source is connected to said collector; and

one terminal of said charging capacitor is also connected to said collector.

33. An electrical circuit as claimed in claim 32 wherein said forward conduction path is the collector-emitter path.

34. An electrical circuit as claimed in claim 32 wherein said forward conduction path is the collector-base path.

35. The electrical circuit of claim 29 which includes a delay line forming said capacitor.

36. An electrical circuit as in claim 30 wherein said inductor produces essentially a single sine wave cycle of voltage representing an oscillation frequency determined essentially by the ratio of the inductance of said inductor to the resistance of said forward conduction path of said transistor during breakdown.

37. An electrical circuit as in claim 33 wherein said coupling capacitor is connected to the base of said transistor, and which further includes a bias resistor having one end connected to the base of said transistor, said inductor being connected between the other end of said bias resistor and the emitter of said transistor.

38. An electrical circuit as in claim 34 wherein said coupling capacitor is connected to the emitter of said transistor, said first series loop further includes a load resistor connected between said inductor and said charging capacitor, and which further includes a bias resistor connected between the emitter of said transistor and said load resistor.

39. An electrical circuit as in claim 38 wherein said antenna means is connected to the juncture between said inductor and said load resistor.

40. An electrical circuit as in claim 29 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

41. An electrical circuit as in claim 29 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

42. An electrical circuit as in claim 33 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

43. An electrical circuit as in claim 33 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

44. An electrical circuit as in claim 35 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

46. An electrical circuit as in claim 37 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

47. An electrical circuit as in claim 37 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

48. An electrical circuit as in claim 39 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

49. An electrical circuit as in claim 39 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

45. An electrical circuit as in claim 45 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

50. An electrical circuit for generating and transmitting very short and widely separated high frequency sine-wave pulses of electrical energy, comprising:

a transistor of the N-P-N type having a base, a collector, and emitter, and a forward conduction path extending from its collector to its emitter;

a discharge circuit including a delay line and an inductor connected in a first series loop with said forward conduction path of said transistor, said inductor being connected to said emitter;

a triggering circuit including a coupling capacitor connected to said base of said transistor to provide an input for triggering it into its breakdown or avalanche mode;

an antenna connected in parallel with said inductor for transmitting electromagnetic energy into space;

a recharging circuit including a charging resistor and a bias voltage source coupled with said delay line into a second series loop, said bias voltage source being capable of biasing the forward conduction path of the transistor near its breakdown condition; and

the time constant of said recharging circuit being at least many times greater than the time constant of said discharge circuit, so that when current is being discharged from said delay line into said inductor through said forward conduction path of said transistor the avalanche mode current carriers will recombine and end the low resistance avalanche mode upon exhaustion of the charge stored in the charge line.

51. An electrical circuit as in claim 50 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

52. An electrical circuit as in claim 50 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

53. An electrical circuit utilizing a transistor in the avalanche mode for generating and transmitting very short and widely separated high frequency sine-wave pulses of electrical energy, comprising:

a discharge circuit including a charging capacitor and an inductor connected in a first series loop, with two electrodes of the transistor forming its forward conduction path;

a triggering circuit including a coupling capacitor connected to the other electrode of the transistor to provide an input for triggering it into its breakdown or avalanche mode;

antenna means coupled to said inductor for transmitting electromagnetic energy into space;

a recharging circuit including a bias voltage source coupled with said charging capacitor into a second series loop, said bias voltage source being capable of biasing the forward conduction path of the transistor near its breakdown condition; and

said recharging circuit being inoperable for recharging said charging capacitor at least until sufficient current has been discharged from said capacitor into said inductor through said forward conduction path of said transistor to cause the avalanche mode current carriers to recombine so as to end the low resistance avalanche mode.

54. An electrical circuit as in claim 53 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are many times the duration of said single sine wave of voltage.

55. An electrical circuit as in claim 53 wherein said triggering circuit is adapted for triggering said transistor at time intervals that are more than a thousand times the duration of said single sine wave of voltage.

56. The method of generating and transmitting very short and widely separated high frequency sine-wave pulses of electrical energy, comprising:

coupling a transistor, a charging capacitor, and a load device into a first series loop path forming a discharge circuit;

coupling a bias voltage source and the same charging capacitor into a second series loop path forming a recharging circuit with a large RC time constant compared to the first series loop path, the bias voltage source being selected to be capable of biasing the forward conduction path of the transistor near its breakdown condition;

coupling an antenna means to the load device for transmitting electromagnetic energy pulses into space;

sampling an original information signal upon each occurrence of a periodic reference signal; and

in response to the signal samples, triggering the transistor into its breakdown or avalanche mode so as to create a series of successive transmitted pulses whose starting times are modified in accordance with the value of the original information signal upon each occurrence of the periodic reference signal.

57. The method of claim 56 wherein the time period of the periodic reference signal is at least many times the length of each transmitted pulse.