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US4345211A
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Digital phaselock demodulator
Assignee: Boeing North American Inc
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Filing: 1980-09-15
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Granted: 1982-08-17
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Expires: 2000-09-15
Abstract
Abstract A digital phaselock demodulator suitable for demodulating a variety of phase or frequency modulated signals including an FM'd VOR signal component. A digital phase detector receives the modulated input signal and a feedback signal, and outputs demodulated signal. Two sets of digital words of different word rates are provided wherein one set is reversible in order as a function of phase between input and feedback signals. Digital word comparison occasions the feedback signal.
Inventors
- 👤 Joe D. Longworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:03
CPC Classifications
H; H03; H03K; H03K9/00; H03K9/06
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
210 words
A digital phaselock system for demodulating a frequency modulated or phase modulated signal S in comprising: digital first means, connected for receiving S in and a feedback signal S f , for providing as output a digital signal indicative of phase between S in and S f , second means for providing as output a predetermined number M of different digital words, said words being provided at a rate R 1 , and said words being provided in a forward or reverse order as a function of phase between S in and S f , third means for providing as output a predetermined number N of different digital words, said words being provided at a rate R 2 which is greater than R 1 , comparison fourth means for receiving the second means words and the third means words and for providing a digital output signal when a predetermined relationship between a second means word and a third means word is incurred, fifth means receiving the fourth means output and providing S f to said first means, and sixth means for providing recovered modulation information to utilizing apparatus, said sixth means being connected for receiving a predetermined one of (a) the first means output or (b) the second means output.
Claim 2
Dependent Claim
210 words
A digital phaselock system for demodulating a frequency modulated or phase modulated signal S in comprising: digital first means, connected for receiving S in and a feedback signal S f , for providing as output a digital signal indicative of phase between S in and S f , second means for providing as output a predetermined number M of different digital words, said words being provided at a rate R 1 , and said words being provided in a forward or reverse order as a function of phase between S in and S f , third means for providing as output a predetermined number N of different digital words, said words being provided at a rate R 2 which is greater than R 1 , comparison fourth means for receiving the second means words and the third means words and for providing a digital output signal when a predetermined relationship between a second means word and a third means word is incurred, fifth means receiving the fourth means output and providing S f to said first means, and sixth means for providing recovered modulation information to utilizing apparatus, said sixth means being connected for receiving a predetermined one of (a) the first means output or (b) the second means output.
Claim 3
Dependent Claim
29 words
The system as defined in claim 1 wherein said second means comprises a signal source and an up/down counter appropriately connected thereto for registering counts from said signal source.
Claim 4
Dependent Claim
44 words
The system as defined in claim 2 wherein said signal source comprises a predetermined one of (i) a source of fixed frequency signal or (ii) a source of variable frequency signal whose instantaneous frequency is proportional to the instantaneous frequency of S in .
Claim 5
Dependent Claim
17 words
The system as defined in claim 3 wherein the predetermined one of (i) or (ii) is (ii).
Claim 6
Dependent Claim
46 words
The system as defined in claim 3 wherein the variable frequency signal instantaneous frequency is approximately equal to 2 k times the instantaneous frequency of S in , where k is a predetermined one of (a) zero, (b) a positive integer or (c) a negative integer.
Claim 7
Dependent Claim
19 words
The system as defined in claim 3 wherein the variable frequency signal and S in are synchronized in phase.
Claim 8
Dependent Claim
21 words
The system as defined in claim 3 wherein the source of variable frequency signal comprises means for supplying S in .
Claim 9
Dependent Claim
13 words
The system as defined in claim 1 wherein M is equal to N.
Claim 10
Dependent Claim
18 words
The system as defined in claim 1 where R 2 is no less than approximately 2R 1 .
Claim 11
Dependent Claim
32 words
The system as defined in claim 1 wherein said fourth means provides its output signal when a second means output word and a third means output word simultaneously have the same value.
Claim 12
Dependent Claim
30 words
The system as defined in claim 1 wherein said first means comprises a delay flipflop having D and C inputs connected for receiving, respectively, S in and S f .
Claim 13
Dependent Claim
44 words
The system as defined in claim 11 wherein said second means comprises a signal source and an up/down counter appropriately connected thereto for registering counts therefrom, and said up/down counter is connected for being controlled in direction of counting by the delay flipflop output.
Claim 14
Dependent Claim
24 words
The system as defined in claim 1 wherein, the frequency of S f is proportional to the frequency of the fourth means output signal.
Claim 15
Dependent Claim
16 words
The system as defined in claim 13 wherein S f is the fourth means output signal.
Claim 16
Dependent Claim
22 words
The system as defined in claim 1 wherein (R 2 /N) is approximately equal to the frequency of the S in carrier.
Claim 17
Dependent Claim
13 words
The system as defined in claim 15 wherein M is equal to N.
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) | 1985-08-16 | 1986-02-15 | 1986-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-08-16 | 1990-02-15 | 1990-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-08-16 | 1994-02-15 | 1994-08-17 | $7700.00 | Window Closed / Lapsed |