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US3641437A
Expired / Lapsed
US
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Maximal-ratio diversity receiving system
Assignee: TDK Micronas GmbH
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Filing: 1970-08-14
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Granted: 1972-02-08
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Expires: 1990-08-14
Abstract
Abstract n RF diversity signals are routed to separate channels and heterodyned to n IF signals having the same IF frequency. The IF signals are linearly combined to provide a common IF signal from which an AGC signal is generated and is used to control the gain of each IF signal produced to assure a constant amplitude, common IF signal. This common IF signal is also used as a reference signal for a phase comparator in each channel. Each phase comparator compares the phase of its associated IF signal to the reference signal and adjusts its associated IF signal to be inphase with the other IF signals. A variable impedance diode is coupled to be responsive to each IF signal. The impedance of each diode is controlled by comparing the amplitude of the associated IF signal to the remaining (n-1) IF signals. The IF signal output of each diode is combined to provide a maximal-ratio combined IF signal for utilization in the remainder of the receiver.
Inventors
- 👤 Richard J Gurak
- 👤 Milton D Reicher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:01
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/08; H04B7/0837; H04B7/0842; H04B7/0848; H04B7/0857
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
266 words
A diversity receiving system of the predetection combining type comprising: n sources of signals, the signals of each of said sources having random phase relation with respect to each other, where n is an integer greater than one; first means coupled to said sources to provide n intermediate frequency signals each having the same frequency; n gain control means each coupled to said first means responsive to a different one of said intermediate frequency signals; n variable impedance means each coupled to a different one of said gain control means; second means coupled to said gain control means to linearly combine said intermediate frequency signals; third means coupled to the output of said second means, the output of each of said gain control means and said first means to vary the phase relation of said intermediate frequency signals to render said intermediate frequency signals inphase at the outputs of said first means; fourth means coupled to the output of said second means to produce a control signal for coupling to each of said gain control means to control the amplitude of each of said intermediate frequency signals to produce a constant amplitude signal at the output of said second means; fifth means coupled to the output of each of said gain control means and each of said variable impedance means to control the impedance of each of said variable impedance means to provide square law signal addition; and sixth means coupled to each of said variable impedance means to combine said intermediate frequency signals and provide a maximal-ratio combined output intermediate frequency signal for said system.
Claim 2
Dependent Claim
266 words
A diversity receiving system of the predetection combining type comprising: n sources of signals, the signals of each of said sources having random phase relation with respect to each other, where n is an integer greater than one; first means coupled to said sources to provide n intermediate frequency signals each having the same frequency; n gain control means each coupled to said first means responsive to a different one of said intermediate frequency signals; n variable impedance means each coupled to a different one of said gain control means; second means coupled to said gain control means to linearly combine said intermediate frequency signals; third means coupled to the output of said second means, the output of each of said gain control means and said first means to vary the phase relation of said intermediate frequency signals to render said intermediate frequency signals inphase at the outputs of said first means; fourth means coupled to the output of said second means to produce a control signal for coupling to each of said gain control means to control the amplitude of each of said intermediate frequency signals to produce a constant amplitude signal at the output of said second means; fifth means coupled to the output of each of said gain control means and each of said variable impedance means to control the impedance of each of said variable impedance means to provide square law signal addition; and sixth means coupled to each of said variable impedance means to combine said intermediate frequency signals and provide a maximal-ratio combined output intermediate frequency signal for said system.
Claim 3
Dependent Claim
38 words
A system according to claim 1, wherein each of said gain control means includes an intermediate frequency amplifier with automatic gain control means; and further including a conductor interconnecting each of said amplifiers to compensate for variations therein.
Claim 4
Dependent Claim
16 words
A system according to claim 1, wherein each of said variable impedance means includes a diode.
Claim 5
Dependent Claim
70 words
A system according to claim 1, wherein said third means includes n phase comparators each coupled to the output of a different one of said gain control means and said second means, the outputs of each of said phase comparators being coupled to said first means to vary the phase relation of said intermediate frequency signals to render said intermediate frequency signals inphase at the outputs of said first means.
Claim 6
Dependent Claim
74 words
A system according to claim 1, wherein said first means includes n mixer means each coupled to a different one of said sources, and n variable frequency oscillator means each coupled to a different one of said mixer means, each of said oscillator means being controlled by said third means to vary the phase relation of said intermediate frequency signals to render said intermediate frequency signals inphase at the outputs of said mixer means.
Claim 7
Dependent Claim
214 words
A system according to claim 1, wherein n is equal to two; said variable impedance means includes a first diode having its input electrode coupled to the output of one of said gain control means and its output electrode coupled to said sixth means, and a second diode having its input electrode coupled to the output of the other of said gain control means and its output electrodes coupled to said sixth means; and said fifth means includes a reference voltage coupled to the output electrodes of each of said first and second diodes, seventh means coupled to the output of both of said gain control means to produce a first voltage equal to the algebraic addition of the positive peak of one of said intermediate frequency signals and the negative peak of the other of said intermediate frequency signals, said first voltage being coupled to the input electrode of said first diode, and eighth means coupled to the output of both of said gain control means to produce a second voltage equal to the algebraic addition of the positive peak of said other of said intermediate frequency signal and the negative peak of said one of said intermediate frequency signals, said second voltage being coupled to the input electrode of said second diode.
Claim 8
Dependent Claim
129 words
A system according to claim 6, wherein said seventh means includes a first positive peak detector coupled to one of said gain control means, a first negative peak detector coupled to the other of said gain control means, a first resistor coupled between the outputs of said first positive and negative peak detectors, and a first amplifier coupled to said first resistor to provide said first voltage; and said eighth means includes a second positive peak detector coupled to said other of said gain control means, a second negative peak detector coupled to said one of said gain control means, a second resistor coupled between the outputs of said second positive and negative peak detectors, and a second amplifier coupled to said second resistor to provide said seconD voltage.
Claim 9
Dependent Claim
92 words
A system according to claim 1, wherein n is equal to an integer greater than two; each of said variable impedance means including a diode having its input electrode coupled to a different one of said gain control means and its output electrode coupled to said sixth means; and said fifth means includes n maximal-ratio circuits each coupled to a different one of said diodes and the output of all of said gain control means to control the impedance of the associated one of said diodes to provide square law signal addition.
Claim 10
Dependent Claim
96 words
A system according to claim 8, wherein each of said maximal-ratio circuits includes a reference voltage coupled to the output electrode of the associated one of said diodes, and seventh means coupled to the output of all of said gain control means to produce a control voltage equal to the algebraic addition of the positive peak of one of said intermediate frequency signals and the negative peak of a predetermined value of the remaining (n-1) of said intermediate frequency signal, said control voltage being coupled to the input electrode of the associated one of said diodes.
Claim 11
Dependent Claim
129 words
A system according to claim 9, wherein said seventh means includes a positive peak detector coupled to the output of one of said gain control means, eighth means coupled to the output of the remaining (n-1) of said gain control means to provide a signal equal to the average value of the remaining (n-1) of said intermediate frequency signals, a first amplifier having a predetermined gain coupled to the output of said eighth means, a negative peak detector coupled to the output of said first amplifier, a resistor coupled between the output of said positive and negative peak detector, and a second amplifier having a given gain coupled to said resistor to provide said control voltage for coupling to the input electrode of the associated one of said diodes.
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) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |