Precision microwave/millimeter wave modulated signal source

• US 6,396,431 B1
• Filed: 09/07/1999
• Issued: 05/28/2002
• Est. Priority Date: 09/07/1999
• Status: Expired due to Fees

• 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: Misra, Gautam, Swanick, David J., Cho, Kichul
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US09/391,881
• Time in Patent Office: 994 Days
• Field of Search: 341/177 455/115,102 370/205,212 324/458,527
• US Class Current: 341/177
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits

Abstract

The precision microwave/millimeter wave modulated signal source is a relatively low cost, compact, highly accurate and stable signal source covering the 2 to 40 Gigahertz frequency range. The pulse width and amplitude level of the output signal can be changed on every pulse in the signal pulse train. Pulse width range is 5 nanoseconds to 1 millisecond. Pulse repetition intervals can be changed between each pulse set with usable range from 10 nanoseconds to 100 milliseconds. Interval parameters can be adjusted with 1 nanosecond resolutions with stabilities of +/−200 picoseconds. The highly accurate and versatile selection of signal parameters, along with its compact size, makes this design useful as an embedded built in test signal source. This built in signal source can be used for verification of system performance for many electronic warfare systems.

Claims

1. An apparatus for producing a high frequency pulse modulated output signal, comprising:

a signal generator for producing a broad-band radio frequency signal comprised of a plurality of discrete frequencies;

a modulator for modulating said broad-band radio frequency signal using a control signal to produce a plurality of pulse modulated discrete frequency signals, said control signal representing a desired signal pulse train; and

means for selecting one of said plurality of pulse modulated discrete frequency signals as the output signal.

2. The apparatus of claim 1 wherein said signal generator comprises:

an oscillator for producing a base frequency signal; and

a step recovery diode for receiving said base frequency signal and for producing said broad-band radio frequency signal.

3. The apparatus of claim 2 wherein said step recovery diode is a comb generator for producing each of said plurality of discrete frequencies.

4. The apparatus of claim 1 wherein said modulator comprises a PIN diode.

5. The apparatus of claim 4 further comprising a microprocessor for producing said control signal based on a desired signal pulse train, said microprocessor providing said control signal to said PIN diode to control pulse modulation of said broad-band radio frequency signal.

6. The apparatus of claim 1 wherein said selecting means comprises a YIG filter.

7. The apparatus of claim 6 wherein said selecting means further comprises a microprocessor for controlling said YIG filter to select one of said plurality of pulse modulated discrete frequencies as the output signal.

8. The apparatus of claim 7 wherein said microprocessor further controls frequency drift of said selected one of said frequencies.

9. The apparatus of claim 5 wherein said selecting means comprises a YIG filter, said microprocessor controlling said YIG filter to select one of said plurality of pulse modulated discrete frequencies signals as the output signal.

10. The apparatus of claim 9 wherein said microprocessor is part of a microprocessor circuit, said microprocessor circuit further comprising:

a plurality of FIFO memories receiving signals from said microprocessor;

a series of programmable logic devices, said plurality of FIFO memories feeding said series of programmable logic devices, one of said programmable logic devices providing said control signal to said PIN diode.

11. The apparatus of claim 1 further comprising a digital attenuator.

12. The apparatus of claim 11 further comprising a microprocessor for controlling said digital attenuator to attenuate the high frequency pulse modulated output signal.

13. The apparatus of claim 12 wherein the high frequency pulse modulated output signal is comprised of a plurality of pulses, each of said pulses being attenuated individually and independently.

14. The apparatus of claim 1 wherein said plurality of pulse modulated discrete frequency signals is comprised of a plurality of pulses and a corresponding plurality of intervals, each of said plurality of pulses having a pulse duration, said pulse duration being a pulse width, each of said plurality of intervals having an interval duration, said interval duration being a pulse repetition interval, wherein:

said modulator modulates said broad band radio frequency signal such that said pulse width of each of said pulses is individually and independently variable; and

said modulator modulates said broad band radio frequency signal such that said pulse repetition interval of each of said intervals is individually and independently variable.

15. The apparatus of claim 14 wherein:

said pulse width has a range between 5 nanoseconds and 1 millisecond with 1 nanosecond resolution; and

said pulse repetition interval has a range between 10 nanoseconds and 100 milliseconds with 1 nanosecond resolution.

16. A method for producing a high frequency pulse modulated output signal, comprising:

generating a broad-band radio frequency signal comprised of a plurality of discrete frequencies;

modulating said broad-band radio frequency signal using a control signal to produce a plurality of pulse modulated discrete frequency signals, said control signal representing a desired signal pulse train; and

selecting one of said plurality of pulse modulated discrete frequencies signals as the output signal.

17. The method of claim 16 wherein said generating step comprises:

providing a base frequency signal; and

receiving said base frequency signal and producing said broad-band radio frequency signal.

18. The method of claim 16 further comprising controlling frequency drift of said selected one of said frequencies.

19. The method of claim 16 further comprising attenuating the high frequency pulse modulated output signal.

20. The method of claim 19 wherein said attenuating step attenuates, individually and independently, each of a plurality of pulses of the high frequency pulse modulated output signal.

21. The method of claim 16 wherein each of said plurality of pulse modulated discrete frequency signals is comprised of a plurality of pulses and a corresponding plurality of intervals, each of said plurality of pulses having a pulse duration, said pulse duration being a pulse width, each of said plurality of intervals having an interval duration, said interval duration being a pulse repetition interval, the method further comprising:

modulating said pulse width of each of said pulses individually and independently; and

modulating said pulse repetition interval of each of said intervals individually and independently.