Patent US3743971A successfully refreshed from Google Patents.
US3743971A
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Vor am modulator
Assignee: Collins Radio Co
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Filing: 1971-09-03
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Granted: 1973-07-03
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Expires: 1991-09-03
Abstract
Abstract Amplitude modulation techniques are applied to a 9960 Hz subcarrier signal of the type defined by VOR navigation systems by means separately applying a 30 Hz variable phase test signal and a 9960 Hz subcarrier reference phase signal to an amplitude modulation means with the modulation means acting on the 9960 Hz frequency modulated subcarrier alone and selectively introducing controlled amplitude modulation levels of predetermined amplitude modulation components as exist in VOR transmission, with subsequent recombination with the 30 Hz variable phase signal to provide a selectively controlled composite modulation signal comprising a 30 Hz variable phase signal and a 9960 Hz frequency modulated reference subcarrier, the latter signal being amplitude modulated at selected modulation levels with predetermined amplitude modulation frequency components.
Inventors
- 👤 W Hemme
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:08
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/02; G01S1/022; G01S1/028
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
126 words
Means for amplitude modulating a carrier signal at a selected modulation level by a modulating signal source, comprising isolation amplifier means to which said carrier signal is applied as input, first linear signal mixing means to which said modulating signal is applied as a first input, a variable direct current voltage signal source applied as a second input to said first linear signal mixing means, signal multiplying means, the outputs from said first linear signal mixing means and said isolation amplifier means being applied as respective inputs to said signal multiplying means, the output from said signal multiplying means comprising said carrier signal amplitude modulated by said modulation input signal and with a percentage modulation level proportional to the magnitude of said variable DC voltage source.
Claim 2
Dependent Claim
126 words
Means for amplitude modulating a carrier signal at a selected modulation level by a modulating signal source, comprising isolation amplifier means to which said carrier signal is applied as input, first linear signal mixing means to which said modulating signal is applied as a first input, a variable direct current voltage signal source applied as a second input to said first linear signal mixing means, signal multiplying means, the outputs from said first linear signal mixing means and said isolation amplifier means being applied as respective inputs to said signal multiplying means, the output from said signal multiplying means comprising said carrier signal amplitude modulated by said modulation input signal and with a percentage modulation level proportional to the magnitude of said variable DC voltage source.
Claim 3
Dependent Claim
55 words
Modulation means as defined in claim 1 wherein said signal multiplying means comprises means for selectively adjusting the output level thereof and including means to null out undesired modulation products from said analog multiplier output as effected by voltage offsets in the carrier signal input to said multiplier as applied from said isolation amplifier means.
Claim 4
Dependent Claim
100 words
Modulation means as defined in claim 2 including a further linear signal mixing means to which the output from said multiplier means is applied as a first input, and means for applying a selectively variable level further input signal as second input to said further linear signal mixing means, the output from said further linear mixing means comprising said subcarrier input signal amplitude modulated at a selected modulation level at at least one of a plurality of tonal modulation input signals as applied to said first linear signal mixing means together with a selected level of said first input signal.
Claim 5
Dependent Claim
90 words
Modulation means as defined in claim 3 wherein said carrier signal input comprises a 9960 Hz subcarrier frequency modulated at a deviation rate of 30 Hz, said modulating signal input comprising at least one of tonal modulation signals of 30 Hz, 60 Hz, and 1500 Hz, and said further input signal comprising a 30 Hz input signal, whereby the output from said further linear mixing means comprises a composite VOR modulation signal with the subcarrier component thereof further amplitude modulated at a selected modulation level by said modulating signal input.
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) | 1976-07-02 | 1977-01-01 | 1977-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-02 | 1981-01-01 | 1981-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-02 | 1985-01-01 | 1985-07-03 | $7700.00 | Window Closed / Lapsed |