US4644299A
Expired / Lapsed
US
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Multimode noise generator using digital FM
Assignee: Raytheon Co
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Filing: 1986-02-14
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Granted: 1987-02-17
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Expires: 2006-02-14
Abstract
Abstract A pseudorandom noise generator which operates in different modes is disclosed. The pseudorandom noise generator (10) includes circuitry (11,13) for providing a digital signal having a pseudorandom sequence at a selected clock rate; a modulation control circuit (15, 17, 20, 23) for selectively providing a modulation control signal that corresponds to either a non-filtered or filtered version of the digital signal, and for controlling the mode of operation of the noise generator; a modulation circuit (27, 29, 31, 33) responsive to the modulation control signal for providing a modulation signal; and a voltage controlled oscillator (VCO) (35) responsive to the modulation signal for providing a VCO output having a relatively constant output spectrum and high spectral containment for each mode of operation pursuant to control by the modulation control circuit and the modulation circuit.
Inventors
- 👤 Frank Amoroso
- 👤 John S. Cullings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:08
CPC Classifications
H; H03; H03B; H03B29/00
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
111 words
A noise generator comprising: means for providing a digital signal having a pseudorandom sequence at a selected clock rate; modulation control means for selectively providing a modulation control signal that corresponds to either a non-filtered or filtered version of said digital signal, said modulation control means controlling the mode of operation of the noise generator; modulation means responsive to said modulation control signal for providing a modulation signal; and a voltage controlled oscillator (VCO) responsive to said modulation signal for providing a VCO output having a relatively constant output spectrum and high spectral containment for each mode of operation pursuant to control by said modulation control means and said modulation means.
Claim 2
Dependent Claim
111 words
A noise generator comprising: means for providing a digital signal having a pseudorandom sequence at a selected clock rate; modulation control means for selectively providing a modulation control signal that corresponds to either a non-filtered or filtered version of said digital signal, said modulation control means controlling the mode of operation of the noise generator; modulation means responsive to said modulation control signal for providing a modulation signal; and a voltage controlled oscillator (VCO) responsive to said modulation signal for providing a VCO output having a relatively constant output spectrum and high spectral containment for each mode of operation pursuant to control by said modulation control means and said modulation means.
Claim 3
Dependent Claim
34 words
The noise generator of claim 1 wherein said modulation control means includes a low pass filter responsive to said digital signal for providing said filtered version of said digital signal to said modulation means.
Claim 4
Dependent Claim
38 words
The noise generator of claim 2 wherein said low pass filter has a time constant which is selected to provide a relatively constant probability density function for said filtered version of said digital signal over its voltage range.
Claim 5
Dependent Claim
30 words
The noise generator of claim 3 wherein said modulation control means includes switching circuitry for bypassing said low pass filter to directly provide said digital signal to said modulation means.
Claim 6
Dependent Claim
71 words
The noise generator of claim 4 wherein said modulation control means provides for two modes of operation including (a) a first mode of operation wherein a low index of modulation is utilized and said digital signal is provided to said modulation means, and (b) a second mode of operation wherein a high index of modulation is utilized and said filtered version of said digital signal is provided to said modulation means.
Claim 7
Dependent Claim
69 words
The noise generator of claim 5 wherein said modulation means comprises: means for controlling the level of said modulation control signal; an operational amplifier responsive to said modulation control signal for providing said modulation signal which has a swing determined by the level of said modulation control signal; and means for controlling the offset of said operational amplifier which determines the center frequency of the output of said VCO.
Claim 8
Dependent Claim
35 words
The noise generator of claim 6 wherein said level control means controls the modulation index for said first mode of operation and controls the bandwidth of said VCO output for said second mode of operation.
Claim 9
Dependent Claim
30 words
The noise generator of claim 7 wherein said level controlling means is adjusted in said first mode of operation to control said VCO output to have a maximally flat spectrum.
Claim 10
Dependent Claim
14 words
The noise generator of claim 6 wherein said level controlling means includes a potentiometer.
Claim 11
Dependent Claim
14 words
The noise generator of claim 6 wherein said offset controlling means includes a potentiometer.
Claim 12
Dependent Claim
69 words
A noise generator comprising: means for providing a digital signal having a pseudorandom sequence at a selected clock rate; a voltage controlled oscillator (VCO); and control means responsive to said digital signal for selectively controlling the mode of operation of the noise generator and for modulating said VCO to provide a VCO output which has a relatively constant output spectrum and high spectral containment for each mode of operation.
Claim 13
Dependent Claim
69 words
A noise generator comprising: means for providing a digital signal having a pseudorandom sequence at a selected clock rate; a voltage controlled oscillator (VCO); and control means responsive to said digital signal for selectively controlling the mode of operation of the noise generator and for modulating said VCO to provide a VCO output which has a relatively constant output spectrum and high spectral containment for each mode of operation.
Claim 14
Dependent Claim
77 words
The noise generator of claim 11 wherein said control means comprises: filter means selectively responsive to said digital signal for providing a baseband version of said digital signal; modulation means for providing a modulation signal to said VCO; and switching means responsive to said digital signal for selectively providing to said modulation means a modulation control signal which is either said digital signal or a baseband version of said digital signal as provided by said filter means.
Claim 15
Dependent Claim
29 words
The noise generator of claim 12 wherein said filter means comprises a low pass filter having a time constant adjusted pursuant to said clock rate of said digital signal.
Claim 16
Dependent Claim
32 words
The noise generator of claim 13 wherein said time constant is selected to provide a relatively constant probability density function for said baseband version of said digital signal over its voltage range.
Claim 17
Dependent Claim
70 words
The noise generator of claim 12 wherein said control means provides for two modes of operation including (a) a first mode of operation wherein a low index of modulation is utilized and said digital signal is provided to said modulation means, and (b) a second mode of operation wherein a high index of modulation is utilized and said baseband version of said digital signal is provided to said modulation means.
Claim 18
Dependent Claim
69 words
The noise generator of claim 15 wherein said modulation means comprises: means for controlling the level of said modulation control signal; an operational amplifier responsive to said modulation control signal for providing said modulation signal which has a swing determined by the level of said modulation control signal; and means for controlling the offset of said operational amplifier which determines the center frequency of the output of said VCO.
Claim 19
Dependent Claim
35 words
The noise generator of claim 16 wherein said level control means controls the modulation index for said first mode of operation and controls the bandwidth of said VCO output for said second mode of operation.
Claim 20
Dependent Claim
30 words
The noise generator of clam 17 wherein said level controlling means is adjusted in said first mode of operation to control said VCO output to have a maximally flat spectrum.
Claim 21
Dependent Claim
30 words
The noise generator of clam 17 wherein said level controlling means is adjusted in said first mode of operation to control said VCO output to have a maximally flat spectrum.
Claim 22
Dependent Claim
14 words
The noise generator of claim 16 wherein said level controlling means includes a potentiometer.
Claim 23
Dependent Claim
14 words
The noise generator of claim 16 wherein said offset controlling means includes a potentiometer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-16 | 1990-08-18 | 1991-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-16 | 1994-08-18 | 1995-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-16 | 1998-08-18 | 1999-02-17 | $7700.00 | Window Closed / Lapsed |