Systems and methods for generating pulsed output signals using a gated RF oscillator circuit

• US 20100277248A1
• Filed: 05/01/2009
• Published: 11/04/2010
• Est. Priority Date: 05/01/2009
• Status: Active Grant

• Current Assignee: L-3 Communications Integrated Systems LP (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Integrated Systems LP (L3Harris Technologies, Inc.)
• Inventors: Rutherford, Brian C., McClain, Ross A. JR.
• Granted Patent: US 8,665,035 B2
• Time in Patent Office: Days
• US Class Current: 331/108R
• CPC Class Codes: H03K 3/28 using means other than a transformer for feedback
• CPC Class Codes: H03K 3/80 Generating trains of sinusoidal oscillations by keying or interruption of sinusoidal oscillations H03C; for transmission of digital information H04L

Abstract

Systems and methods for generating pulsed output signals that employ a gated RF oscillator circuit having an output that is switchably grounded through the emitter of a transistor and including feedback from the output of the circuit to the base of the transistor to create oscillations and to allow a digital input pulse of a desired length to control the start and stop of oscillations created by the transistor.

Claims

1. Oscillator circuitry, comprising:

a transistor switching element having a control terminal, input terminal and output terminal, the input terminal of the transistor switching element being coupled to a power source and an output of the oscillator circuitry, the control terminal of the transistor switching element being coupled to an input voltage pulse source, and the output terminal of the transistor being coupled to ground; and

a feedback path coupled between the input terminal and control terminal of the transistor switching element;

wherein the transistor switching element remains in the off condition during the absence of an input voltage pulse applied to the control terminal of the transistor switching element; and

wherein the transistor switching element cycles between on and off in response to an input voltage pulse applied to the control terminal of the transistor switching element while voltage is supplied from the power source to the input terminal of the transistor element to generate voltage oscillations at the output of the oscillator circuitry for the duration of time that the input voltage pulse is applied to the control terminal of the transistor device, the transistor device coupling the power source to ground each time the transistor cycles to the on condition, and the transistor device isolating the power source from ground each time the transistor cycles to the off condition.

2. The oscillator circuitry of claim 1, wherein the transistor switching element is a bipolar junction transistor device;

wherein the control terminal is a base;

wherein the input terminal is a collector;

wherein the output terminal is an emitter;

wherein the transistor switching element turns on in less than a nanosecond to couple the power source to ground and then turns off in less than a nanosecond to isolate the power source from ground; and

wherein the frequency of the voltage oscillations generated at the output of the oscillator circuitry is from about 3GHz to about 30GHz.

3. The oscillator circuitry of claim 1, further comprising a DC blocking capacitor coupled between the power source and the output of the oscillator circuitry.

4. The oscillator circuitry of claim 1, wherein the feedback path is coupled to the control terminal of the transistor switching element at a first node;

and wherein the oscillator circuitry further comprises a first resistor coupled between the power source and the first node, and a second resistor coupled between the power source and the input terminal of the transistor switching element.

5. The oscillator circuitry of claim 1, wherein the control terminal of the transistor switching element is coupled to ground.

6. The oscillator circuitry of claim 1, wherein the feedback path is coupled to the control terminal of the transistor switching element at a first node;

wherein the control terminal of the switching element is coupled to ground;

wherein the oscillator circuitry further comprises;

a first resistor coupled between the power source and the first node,

a second resistor coupled between the power source and the input terminal of the transistor switching element,

a third resistor coupled between the control terminal of the transistor switching element and ground, and

a first blocking capacitor coupled between the power source and the output of the oscillator circuitry;

wherein the feedback path comprises a fourth resistor and a second blocking capacitor coupled in series between the first node and the output of the oscillator circuitry.

7. A RF signal generation system, comprising:

input pulse creation circuitry configured to produce an input voltage pulse; and

oscillator circuitry having a signal input coupled to receive the input voltage pulse from the input pulse creation circuitry, having a signal output to produce an RF output signal, and having a power input coupled to receive power from a power source;

wherein the oscillator circuitry comprises;

a transistor switching element having a control terminal, input terminal and output terminal, the input terminal of the transistor switching element being coupled to the power input of the oscillator circuitry and the signal output of the oscillator circuitry, the control terminal of the transistor switching element being coupled to the signal output of the oscillator circuitry, and the output terminal of the transistor being coupled to ground, and

a feedback path coupled between the input terminal and control terminal of the transistor switching element,

wherein the transistor switching element remains in the off condition during the absence of an input voltage pulse applied to the control terminal of the transistor switching element, and

wherein the transistor switching element cycles between on and off in response to an input voltage pulse applied to the control terminal of the transistor switching element while voltage is supplied from the power source to the input terminal of the transistor element to generate voltage oscillations at the output of the oscillator circuitry for the duration of time that the input voltage pulse is applied to the control terminal of the transistor device, the transistor device coupling the power source to ground each time the transistor cycles to the on condition, and the transistor device isolating the power source from ground each time the transistor cycles to the off condition.

8. The system of claim 7, wherein the transistor switching element is a bipolar junction transistor device;

wherein the control terminal is a base;

wherein the input terminal is a collector; and

wherein the output terminal is an emitter.

9. The system of claim 8, wherein the input pulse creation circuitry is configured to produce and supply an intermittent input voltage pulse to the signal input of the oscillator circuitry;

and wherein the oscillator circuitry is coupled to a power source that is configured to only supply power to the power input of the oscillator circuitry at the same time an intermittent input voltage pulse is supplied to the signal input of the oscillator circuitry, and to not supply power to the power input of the oscillator circuitry when an intermittent input voltage pulse is not being supplied to the signal input of the oscillator circuitry.

10. The system of claim 9, wherein the input pulse creation circuitry comprises pulse sequence control circuitry and pulse generator circuitry, the pulse sequence control circuitry being configured to simultaneously control the supply of power and a pulse sequence signal to the pulse generator circuitry such that power is only supplied to the pulse generator circuitry when a pulse sequence signal is provided to the pulse generator circuitry, and the pulse generator circuitry being configured to produce and supply the intermittent input voltage pulse to the signal input of the oscillator circuitry for the duration of the pulse sequence signal provided by the pulse sequence control circuitry;

and wherein the pulse sequence control circuitry is further configured to control the supply of power from the power source to the power input of the oscillator circuitry such that power is supplied to the power input of the oscillator circuitry at the same time an intermittent input voltage pulse is supplied to the signal input of the oscillator circuitry, and such that power is not supplied to the power input of the oscillator circuitry when an intermittent input voltage pulse is not being supplied to the signal input of the oscillator circuitry .

11. The system of claim 8, further comprising an antenna coupled to receive the RF output signal from the oscillator circuitry.

12. The system of claim 8, wherein the RF output signal is a RF signal in the range of from 3.1 GHz to 10.6 GHz at a limited transmit power of −

41.3 dBm/MHz with an emitted signal bandwidth that exceeds the lesser of 500 MHz or 20% of the center frequency.

13. A method for generating an oscillating signal, comprising:

providing oscillator circuitry comprising;

a transistor switching element having a control terminal, input terminal and output terminal, the input terminal of the transistor switching element being coupled to a power source and an output of the oscillator circuitry, the control terminal of the transistor switching element being coupled to an input voltage pulse source, and the output terminal of the transistor being coupled to ground, and

a feedback path coupled between the input terminal and control terminal of the transistor switching element;

maintaining the transistor switching element in an off condition during the absence of an input voltage pulse applied to the control terminal of the transistor switching element; and

simultaneously supplying voltage to the input terminal of the transistor element and applying an input voltage pulse to the control terminal of the transistor switching element to cause the transistor switching element to cycle between on and off so as to generate voltage oscillations at the output of the oscillator circuitry for the duration of time that the input voltage pulse is applied to the control terminal of the transistor device, the transistor device coupling the power source to ground each time the transistor cycles to the on condition, and the transistor device isolating the power source from ground each time the transistor cycles to the off condition.

14. The method of claim 13, wherein the transistor switching element is a bipolar junction transistor device;

wherein the control terminal is a base;

wherein the input terminal is a collector;

wherein the output terminal is an emitter;

wherein the transistor switching element turns on in less than a nanosecond to couple the power source to ground and then turns off in less than a nanosecond to isolate the power source from ground; and

wherein the frequency of the voltage oscillations generated at the output of the oscillator circuitry is from about 3 GHz to about 30 GHz.

15. The system of claim 13, wherein the transistor switching element is a bipolar junction transistor device;

wherein the control terminal is a base;

wherein the input terminal is a collector;

wherein the output terminal is an emitter;

wherein the RF output signal is a RF signal in the range of from 3.1 GHz to 10.6 GHz at a limited transmit power of −

41.3 dBm/MHz with an emitted signal bandwidth that exceeds the lesser of 500 MHz or 20% of the center frequency.

16. The method of claim 13, further comprising providing a DC blocking capacitor coupled between the power source and the output of the oscillator circuitry.

17. The method of claim 13, wherein the feedback path is coupled to the control terminal of the transistor switching element at a first node;

and wherein the method further comprises providing a first resistor coupled between a power source and the first node and a second resistor coupled between the power source and the input terminal of the transistor switching element, and supplying the voltage to the input terminal of the transistor element from the power source.

18. The method of claim 13, wherein the control terminal of the transistor switching element is coupled to ground.

19. The method of claim 13, wherein the feedback path is coupled to the control terminal of the transistor switching element at a first node;

wherein the control terminal of the switching element is coupled to ground;

wherein the method further comprises;

providing a first resistor coupled between the power source and the first node,

providing a second resistor coupled between the power source and the input terminal of the transistor switching element,

providing a third resistor coupled between the control terminal of the transistor switching element and ground, and

providing a first blocking capacitor coupled between the power source and the output of the oscillator circuitry,

providing the feedback path with a fourth resistor and a second blocking capacitor coupled between the first node and the output of the oscillator circuitry.

20. The method of claim 13, further comprising:

providing input pulse creation circuitry coupled to a signal input of the oscillator circuitry, the control terminal of the transistor switching element being coupled to the signal input;

providing a power source coupled to a power input of the oscillator circuitry, the input terminal of the transistor switching element being coupled to the power input;

supplying an intermittent input voltage pulse from the pulse creation circuitry to the signal input of the oscillator circuitry;

supplying power from the power source to a power input of the oscillator circuitry at the same time an intermittent input voltage pulse is supplied to the signal input of the oscillator circuitry, and not supplying power to the power input of the oscillator circuitry when an intermittent input voltage pulse is not being supplied to the signal input of the oscillator circuitry;

producing a RF output signal at a signal output of the oscillator circuitry, the signal output being coupled to the input terminal of the transistor switching element, and the RF output signal being produced in response to the intermittent input voltage pulse applied through the signal input to the control terminal of the transistor switching element while voltage is supplied through the power input to the input terminal of the transistor element to generate voltage oscillations of the RF output signal at the signal output of the oscillator circuitry for the duration of time that the input voltage pulse is applied to the control terminal of the transistor device, the transistor device coupling the power source to ground each time the transistor cycles to the on condition, and the transistor device isolating the power source from ground each time the transistor cycles to the off condition.

21. The method of claim 20, wherein the input pulse creation circuitry comprises pulse sequence control circuitry and pulse generator circuitry;

and wherein the method further comprises;

using the pulse sequence control circuitry to simultaneously control the supply of power and a pulse sequence signal to the pulse generator circuitry such that power is only supplied to the pulse generator circuitry when a pulse sequence signal is provided to the pulse generator circuitry,

using the pulse generator circuitry to produce and supply the intermittent input voltage pulse to the signal input of the oscillator circuitry for the duration of the pulse sequence signal provided by the pulse sequence control circuitry, and

using the pulse sequence control circuitry to control the supply of power from the power source to the power input of the oscillator circuitry such that power is supplied to the power input of the oscillator circuitry at the same time an intermittent input voltage pulse is supplied to the signal input of the oscillator circuitry, and such that power is not supplied to the power input of the oscillator circuitry when an intermittent input voltage pulse is not being supplied to the signal input of the oscillator circuitry.

22. The method of claim 13, further comprising providing an antenna coupled to the signal output of the oscillator circuitry;

and providing the RF output signal from the signal output of the oscillator circuitry to the antenna.