US4359692A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rapid acquisition shift keyed signal demodulator
Assignee: Motorola Solutions Inc
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Filing: 1980-11-07
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Granted: 1982-11-16
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Expires: 2000-11-07
Abstract
Abstract A shift keyed phase detector having a first input for receiving a signal including data shift keyed modulated on a carrier, such as BPSK, QPSK, MSK, SMSK, etc., and a second input for receiving a reference frequency from a local oscillator, to supply in-phase and quadrature channel data signals at differing phase error angles relative to the local oscillator reference frequency. The in-phase and quadrature channel signals are squared, and the squared signals are summed and filtered to provide a first phase error signal. The in-phase and quadrature channel signals are also multiplied with each other and filtered to provide a second phase error signal. The in-phase and quadrature channel signals are cross-multiplied with each of the phase error signals and then combined to provide a data signal in phase with the original data signal.
Inventors
- 👤 Carl R. Ryan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:06
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/233; H04L27/2332; H04L27/10; H04L27/14; H04L27/144; H04L27/152; H04L27/1525
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
173 words
A rapid acquisition carrier demodulator comprising: (a) a shift keyed phase detector having an input for receiving a signal including data shift keyed modulated on a carrier, a local oscillator connected to supply a reference frequency to said phase detector, and an in-phase channel and a quadrature channel each providing a signal generated from the received signal and each including data at differing phase error angles relative to the local oscillator reference frequency; (b) first combining means coupled to said phase detector to receive the in-phase and quadrature channel signals and generate a plurality of phase error signals differing from each other by a fixed phase angle; (c) low pass filter means coupled to pass the plurality of phase error signals and substantially reduce noise prevalent in the plurality of phase error signals; and (d) second combining means coupled to said phase detector and said low pass filter means to receive the in-phase and quadrature channel signals and the plurality of phase error signals for combining the signals to provide a data signal.
Claim 2
Dependent Claim
173 words
A rapid acquisition carrier demodulator comprising: (a) a shift keyed phase detector having an input for receiving a signal including data shift keyed modulated on a carrier, a local oscillator connected to supply a reference frequency to said phase detector, and an in-phase channel and a quadrature channel each providing a signal generated from the received signal and each including data at differing phase error angles relative to the local oscillator reference frequency; (b) first combining means coupled to said phase detector to receive the in-phase and quadrature channel signals and generate a plurality of phase error signals differing from each other by a fixed phase angle; (c) low pass filter means coupled to pass the plurality of phase error signals and substantially reduce noise prevalent in the plurality of phase error signals; and (d) second combining means coupled to said phase detector and said low pass filter means to receive the in-phase and quadrature channel signals and the plurality of phase error signals for combining the signals to provide a data signal.
Claim 3
Dependent Claim
55 words
A rapid acquisition carrier demodulator as claimed in claim 1 wherein the first combining means is constructed to generate two phase error signals in the general form of sin Nφ and cos Nφ, where N is a positive integer and φ is the phase error angle between the received signal carrier and the local oscillator.
Claim 4
Dependent Claim
39 words
A rapid acquisition carrier demodulator as claimed in claim 2 wherein the shift keyed phase detector is constructed for receiving one of biphase shift keyed and serial minimum phase shift keyed modulated signals and N is equal to 2.
Claim 5
Dependent Claim
36 words
A rapid acquisition carrier demodulator as claimed in claim 1 wherein the second combining means includes a plurality of multipliers connected to cross-multiply the in-phase and quadrature channel signals with the plurality of phase error signals.
Claim 6
Dependent Claim
43 words
A rapid acquisition carrier demodulator as claimed in claim 4 wherein the second combining means further includes a plurality of summing circuits connected to the plurality of multipliers for combining the cross-multiplied signals to provide output signals representative of in-phase and quadrature data.
Claim 7
Dependent Claim
40 words
A rapid acquisition carrier demodulator as claimed in claim 5 wherein the second combining means further includes a hybrid coupler connected to receive the in-phase and quadrature data signals and supply a single output signal representative of the original data.
Claim 8
Dependent Claim
56 words
A rapid acquisition carrier demodulator as claimed in claim 1 wherein the low pass filter means includes a plurality of low pass filters, one for each of the plurality of phase error signals and the low pass filters are designed with a frequency response to provide a minimum noise with minimum acquisition time for the demodulator.
Claim 9
Independent Claim
125 words
A method of providing rapid acquisition carrier demodulation in conjunction with a shift keyed phase detector constructed to receive a signal, including data shift keyed modulated on a carrier, and having a local oscillator connected to supply a reference frequency to said detector for providing an in-phase channel signal and a quadrature channel signal, said method comprising the steps of: (a) combining the in-phase and quadrature channel signals to generate a plurality of phase error signals differing from each other by a fixed phase angle; (b) filtering the plurality of phase error signals to substantially reduce the noise therein; (c) combining the filtered phase error signals with the in-phase and quadrature channel signals to provide a data signal substantially similar to the original data signal.
Claim 10
Independent Claim
125 words
A method of providing rapid acquisition carrier demodulation in conjunction with a shift keyed phase detector constructed to receive a signal, including data shift keyed modulated on a carrier, and having a local oscillator connected to supply a reference frequency to said detector for providing an in-phase channel signal and a quadrature channel signal, said method comprising the steps of: (a) combining the in-phase and quadrature channel signals to generate a plurality of phase error signals differing from each other by a fixed phase angle; (b) filtering the plurality of phase error signals to substantially reduce the noise therein; (c) combining the filtered phase error signals with the in-phase and quadrature channel signals to provide a data signal substantially similar to the original data signal.
Claim 11
Dependent Claim
92 words
A method as claimed in claim 8 wherein the step of combining the in-phase and quadrature channel signals includes squaring each signal and summing the squared signals to provide a first phase error signal approximately equal to the cosine of the phase error between the carrier of the received signal and the local oscillator frequency, and multiplying the in-phase and quadrature channel signals together to provide a second phase error signal approximately equal to the sine of the phase error between the carrier of the received signal and the local oscillator frequency.
Claim 12
Dependent Claim
58 words
A method as claimed in claim 8 wherein the step of combining the filtered phase error signals with the in-phase and quadrature channel signals includes cross-multiplying the in-phase and quadrature channel signals with each of the plurality of filtered phase error signals and combining the products to provide a data signal in phase with the original data signal.
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) | 1985-11-15 | 1986-05-17 | 1986-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-15 | 1990-05-17 | 1990-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-15 | 1994-05-17 | 1994-11-16 | $7700.00 | Window Closed / Lapsed |