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US4085367A
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Method and detection of phase and frequency modulation
Assignee: RCA Corp
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Filing: 1976-12-10
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Granted: 1978-04-18
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Expires: 1996-12-10
Abstract
Abstract There is disclosed a measurement and recording system having means for simultaneously displaying and recording the spectrum of a signal and the instantaneous phase of selected spectral components of the signal with respect to a local reference signal. Means are disclosed for displaying and recording the signal element lengths as a function of time. The system and method enables an analysis of digitally modulated signals of unknown modulation. The system also provides a means to detect faults in the system equipment that may be generating signals having undesirable variations in phase, frequency, or amplitude.
Inventors
- 👤 John Chamberlin Williams
- 👤 William Braxton Sisco
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:29
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/0012; H04B; H04B14/00; H04B14/002
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
107 words
A method of determining the frequency and modulation of a signal of unknown frequency and digital modulation comprising the steps of: a. analyzing the frequency components of said digitally modulated signal into frequency component signals; b. detecting the phase variations of each of said frequency components of said signal by comparing each of said frequency component signals with a reference signal having a frequency that is the same frequency, respectively, of each component signal; c. displaying phase variations that exist; d. displaying said frequency components, and e. examining said frequency components display in conjunction with said phase display to determine the modulation of said unknown frequency signal.
Claim 2
Independent Claim
107 words
A method of determining the frequency and modulation of a signal of unknown frequency and digital modulation comprising the steps of: a. analyzing the frequency components of said digitally modulated signal into frequency component signals; b. detecting the phase variations of each of said frequency components of said signal by comparing each of said frequency component signals with a reference signal having a frequency that is the same frequency, respectively, of each component signal; c. displaying phase variations that exist; d. displaying said frequency components, and e. examining said frequency components display in conjunction with said phase display to determine the modulation of said unknown frequency signal.
Claim 3
Dependent Claim
59 words
The method according to claim 1 wherein said unknown frequency signal is derived from equipment that may provide a characteristic signature to said signal and, further comprising the step of analyzing the respective phase and frequency displays to identify changes in the phase of a frequency component indicating thereby a characteristic in the equipment providing said unknown frequency signal.
Claim 4
Dependent Claim
144 words
Apparatus for analyzing the unknown modulation of a complex digitally modulated electromagnetic signal of unknown frequency; a. means for receiving said modulated signal; b. spectrum analyzer means responsive to said modulated signal for analyzing frequency components and providing signals manifesting each of said frequency components; c. frequency synthesizer means for providing a reference signal of a selected frequency; d. means for selecting the frequency of said synthesizer means to correspond to the frequency of each frequency component manifested by said spectrum analyzer means; e. phase detection means responsive to said modulated signal and said reference signal for providing a signal manifesting phase differences between said reference signal and said modulated signal; and f. first means for displaying said frequency component signals and second means for displaying said phase difference signal, both display means conjunctively enabling a determination of the modulation of said complex signal.
Claim 5
Dependent Claim
144 words
Apparatus for analyzing the unknown modulation of a complex digitally modulated electromagnetic signal of unknown frequency; a. means for receiving said modulated signal; b. spectrum analyzer means responsive to said modulated signal for analyzing frequency components and providing signals manifesting each of said frequency components; c. frequency synthesizer means for providing a reference signal of a selected frequency; d. means for selecting the frequency of said synthesizer means to correspond to the frequency of each frequency component manifested by said spectrum analyzer means; e. phase detection means responsive to said modulated signal and said reference signal for providing a signal manifesting phase differences between said reference signal and said modulated signal; and f. first means for displaying said frequency component signals and second means for displaying said phase difference signal, both display means conjunctively enabling a determination of the modulation of said complex signal.
Claim 6
Dependent Claim
37 words
Apparatus according to claim 3 further including an X-Y recorder responsive to said spectrum analyzer signals or to phase detection means signal for displaying said frequency spectrum or said phase difference signal, respectively, in the frequency spectrum.
Claim 7
Dependent Claim
24 words
Apparatus according to claim 3 comprising a Z recorder responsive to said spectrum analyzer to record variations in spectrum as a function of time.
Claim 8
Dependent Claim
23 words
Apparatus according to claim 4 further comprising amplitude display means responsive to said receiving means for displaying variations in amplitude of said signal.
Claim 9
Dependent Claim
35 words
Apparatus according to claim 4 further including cathode ray oscilloscope means coupled to the output of said spectrum analyzer to display spectrum, phase and time-domain magnitude of said modulated received signal as functions of time.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-17 | 1981-10-17 | 1982-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-17 | 1985-10-17 | 1986-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-17 | 1989-10-17 | 1990-04-18 | $7700.00 | Window Closed / Lapsed |