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

• US 8,665,035 B2
• Filed: 05/01/2009
• Issued: 03/04/2014
• Est. Priority Date: 05/01/2009
• Status: Expired due to Fees

• Current Assignee: L-3 Communications Integrated Systems LP (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Integrated Systems LP (L3Harris Technologies, Inc.)
• Inventors: McClain, Ross A. Jr., Rutherford, Brian C.
• Primary Examiner(s): Johnson, Ryan
• Application Number:
  US12/387,490
• Publication Number:
  US 20100277248A1
• Time in Patent Office: 1,768 Days
• Field of Search: 331/165, 331172-174, 331/55, 331/153, 331/108.R, 331/108.B, 331/138, 331/140, 332/149, 332/115, 332/116, 375/268, 375/300, 375/309
• US Class Current: 332/149
• 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, a first node and a second node, the first node 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 second node of the transistor being coupled to ground; and

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

wherein the transistor switching element is configured to remain in the off condition to isolate the first node from the second node and ground during the absence of an input voltage pulse applied to the control terminal of the transistor switching element and wherein the transistor switching element is configured to be in the on position to couple the first node to the second node and ground during the presence of an input voltage pulse applied to the control terminal of the transistor switching element;

wherein the transistor switching element is configured to repetitively cycle between on and off multiple times 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 first node of the transistor element to generate voltage oscillations at the output of the oscillator circuitry for a duration of time that the input voltage pulse is applied to the control terminal of the transistor device, the transistor device being configured to couple the power source to ground each time the transistor cycles to the on condition, and the transistor device being configured to isolate the power source from ground each time the transistor cycles to the off condition;

where a sequence in which the transistor switching element repetitively cycles between on and off multiple times acts to generate the respective voltage oscillations at the output of the oscillator circuitry; and

wherein the transistor switching element is a bipolar junction transistor device and the control terminal is a base of the transistor, or wherein the transistor switching element is a field effect transistor (FET) transistor and the control terminal is a gate of the transistor;

wherein the feedback path is coupled to the control terminal of the transistor switching element at a third node of the circuitry; and

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

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

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

4. The oscillator circuitry of claim 1, wherein the feedback path comprises a series feedback circuit coupled between the first node and control terminal of the transistor switching element.

5. Oscillator circuitry, comprising:

a transistor switching element having a control terminal, a first node and a second node, the first node 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 second node of the transistor being coupled to ground; and

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

wherein the transistor switching element is configured to remain in the off condition to isolate the first node from the second node and ground during the absence of an input voltage pulse applied to the control terminal of the transistor switching element and wherein the transistor switching element is configured to be in the on position to couple the first node to the second node and ground during the presence of an input voltage pulse applied to the control terminal of the transistor switching element;

wherein the transistor switching element is configured to repetitively cycle between on and off multiple times 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 first node of the transistor element to generate voltage oscillations at the output of the oscillator circuitry for a duration of time that the input voltage pulse is applied to the control terminal of the transistor device, the transistor device being configured to couple the power source to ground each time the transistor cycles to the on condition, and the transistor device being configured to isolate the power source from ground each time the transistor cycles to the off condition;

where a sequence in which the transistor switching element repetitively cycles between on and off multiple times acts to generate the respective voltage oscillations at the output of the oscillator circuitry; and

wherein the transistor switching element is a bipolar junction transistor device and the control terminal is a base of the transistor, or wherein the transistor switching element is a field effect transistor (FET) transistor and the control terminal is a gate of the transistor;

wherein the feedback path is coupled to the control terminal of the transistor switching element at a third node of the circuitry;

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

wherein the oscillator circuitry further comprises;

a first resistor coupled between the input voltage pulse source and the third node,

a second resistor coupled between the power source and the first node 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 third node and the output of the oscillator circuitry.

6. The oscillator circuitry of claim 5, wherein the transistor switching element is a bipolar junction transistor device;

wherein the control terminal is a base;

wherein the first node is a collector;

wherein the second node an emitter;

wherein the transistor switching element is configured to turn on in less than a nanosecond to couple the power source to ground and then turn 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.

7. The oscillator circuitry of claim 5, where the transistor switching element is either one of:

a bipolar junction transistor in which the control terminal is a base of the transistor, the first node is a collector of the transistor, and the second node is an emitter of the transistor;

or

a field effect transistor (FET) transistor in which the control terminal is a gate of the transistor, the first node is a source of the transistor, and the second node is a drain of the transistor.

8. The oscillator circuitry of claim 5,

where the transistor switching element is a three-terminal transistor having three terminals that are terminals of the same common transistor, the three terminals being the control terminal of the transistor, a second terminal that is the first node of the transistor, and a third terminal that is the second node of the transistor;

where the control terminal is configured to turn on the transistor by selectably electrically connecting the first node to the second node across the transistor upon application of a higher voltage to the control terminal; and

where the control terminal is configured to selectably turn off the transistor by electrically disconnecting the first node from the second node across the transistor upon application of a lower voltage or no voltage to the control terminal.

9. 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, a first node and a second node, the first node 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 second node of the transistor being coupled to ground, and

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

wherein the transistor switching element is configured to remain in the off condition to isolate the first node from the second node and ground during the absence of an input voltage pulse applied to the control terminal of the transistor switching element and wherein the transistor switching element is configured to be in the on position to couple the first node to the second node and ground during the presence of an input voltage pulse applied to the control terminal of the transistor switching element,

wherein the transistor switching element is configured to repetitively cycle between on and off multiple times 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 first node 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 being configured to couple the power source to ground each time the transistor cycles to the on condition, and the transistor device being configured to isolate the power source from ground each time the transistor cycles to the off condition,

where a sequence in which the transistor switching element repetitively cycles between on and off multiple times acts to generate the respective voltage oscillations at the output of the oscillator circuitry,

wherein the transistor switching element is a bipolar junction transistor device and the control terminal is a base of the transistor, or wherein the transistor switching element is a field effect transistor (FET) transistor and the control terminal is a gate of the transistor;

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 9, further comprising an antenna coupled to receive the RF output signal from the oscillator circuitry.

12. The system of claim 9, 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. The RF signal generation system of claim 9

where the transistor switching element is a three-terminal transistor having three terminals that are terminals of the same common transistor, the three terminals being the control terminal of the transistor, a second terminal that is the first node of the transistor, and a third terminal that is the second node of the transistor;

where the control terminal is configured to turn on the transistor by selectably electrically connecting the first node to the second node across the transistor upon application of a higher voltage to the control terminal; and

where the control terminal is configured to selectably turn off the transistor by electrically disconnecting the first node from the second node across the transistor upon application of a lower voltage or no voltage to the control terminal.

14. The system of claim 9, wherein the feedback path comprises a series feedback circuit coupled between the first node and control terminal of the transistor switching element.

27. The oscillator circuitry of claim 9, wherein the transistor switching element is a bipolar junction transistor device;

wherein the control terminal is a base, wherein the first node is a collector; and

wherein the second node is an emitter.

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

providing oscillator circuitry comprising;

a transistor switching element having a control terminal, a first node and a second node, the first node 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 second node of the transistor being coupled to ground, and

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

maintaining the transistor switching element in an off condition to isolate the first node from the second node and ground during the absence of an input voltage pulse applied to the control terminal of the transistor switching element and placing the transistor switching element in the on position to couple the first node to the second node and ground during the presence of an input voltage pulse applied to the control terminal of the transistor switching element; and

simultaneously supplying voltage to the first node 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 repetitively cycle between on and off multiple times while voltage is supplied to the first node of the transistor element 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;

where a sequence in which the transistor switching element repetitively cycles between on and off multiple times acts to generate the respective voltage oscillations at the output of the oscillator circuitry;

wherein the transistor switching element is a bipolar junction transistor device and the control terminal is a base of the transistor, or wherein the transistor switching element is a field effect transistor (FET) transistor and the control terminal is a gate of the transistor;

wherein the feedback path is coupled to the control terminal of the transistor switching element at a third node of the circuitry; and

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

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

providing oscillator circuitry comprising;

a transistor switching element having a control terminal, a first node and a second node, the first node 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 second node of the transistor being coupled to ground, and

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

maintaining the transistor switching element in an off condition to isolate the first node from the second node and ground during the absence of an input voltage pulse applied to the control terminal of the transistor switching element and placing the transistor switching element in the on position to couple the first node to the second node and ground during the presence of an input voltage pulse applied to the control terminal of the transistor switching element; and

simultaneously supplying voltage to the first node 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 repetitively cycle between on and off multiple times while voltage is supplied to the first node of the transistor element 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;

where a sequence in which the transistor switching element repetitively cycles between on and off multiple times acts to generate the respective voltage oscillations at the output of the oscillator circuitry;

wherein the transistor switching element is a bipolar junction transistor device and the control terminal is a base of the transistor, or wherein the transistor switching element is a field effect transistor (FET) transistor and the control terminal is a gate of the transistor;

wherein the feedback path is coupled to the control terminal of the transistor switching element at a third node of the circuitry;

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

wherein the method further comprises;

providing a first resistor coupled between the input voltage pulse source and the third node,

providing a second resistor coupled between the power source and the first node 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 third node and the output of the oscillator circuitry.

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

providing oscillator circuitry comprising;

a transistor switching element having a control terminal, a first node and a second node, the first node 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 second node of the transistor being coupled to ground, and

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

maintaining the transistor switching element in an off condition to isolate the first node from the second node and ground during the absence of an input voltage pulse applied to the control terminal of the transistor switching element and placing the transistor switching element in the on position to couple the first node to the second node and ground during the presence of an input voltage pulse applied to the control terminal of the transistor switching element; and

simultaneously supplying voltage to the first node 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 repetitively cycle between on and off multiple times while voltage is supplied to the first node of the transistor element 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;

where a sequence in which the transistor switching element repetitively cycles between on and off multiple times acts to generate the respective voltage oscillations at the output of the oscillator circuitry;

wherein the transistor switching element is a bipolar junction transistor device and the control terminal is a base of the transistor, or wherein the transistor switching element is a field effect transistor (FET) transistor and the control terminal is a gate of the transistor; and

where the method further comprises;

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 first node 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 first node 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 first node 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.

18. The method of claim 17, wherein the transistor switching element is a bipolar junction transistor device;

wherein the control terminal is a base;

wherein the first node is a collector;

wherein the second node 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.

19. The method of claim 17, wherein the transistor switching element is a bipolar junction transistor device;

wherein the control terminal is a base;

wherein the first node is a collector;

wherein the second node 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.

20. The method of claim 17, further comprising providing a DC blocking capacitor coupled between the power source and the output of the oscillator circuitry.

21. The method of claim 17, wherein the control terminal of the transistor switching element is coupled to ground.

22. The method of claim 17, 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.

23. The method of claim 17, 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.

24. The method of claim 17, where the transistor switching element is either one of:

a bipolar junction transistor in which the control terminal is a base of the transistor, the first node is a collector of the transistor, and the second node is an emitter of the transistor;

or

a field effect transistor (FET) transistor in which the control terminal is a gate of the transistor, the first node is a source of the transistor, and the second node is a drain of the transistor.

25. The method of claim 17,

where the transistor switching element is a three-terminal transistor having three terminals that are terminals of the same common transistor, the three terminals being a first terminal that is the control terminal of the transistor, a second terminal that is the first node of the transistor, and a third terminal that is the second node of the transistor;

where the control terminal is configured to turn on the transistor by selectably electrically connecting the first node to the second node across the transistor upon application of a higher voltage to the control terminal; and

where the control terminal is configured to selectably turn off the transistor by electrically disconnecting the first node from the second node across the transistor upon application of a lower voltage or no voltage to the control terminal.

26. The method of claim 17, wherein the feedback path comprises a series feedback circuit coupled between the first node and control terminal of the transistor switching element.