US4878252A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modified multi-path detector
Assignee: US Philips Corp
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Filing: 1987-11-30
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Granted: 1989-10-31
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Expires: 2007-11-30
Abstract
Abstract A receiver comprising a multi-path detector which comprises a frequency noise peak detector, an AM-detector and a weighting circuit. When noise peaks and amplitude modulations occur in an antenna input signal selected by a diversity switch on account of a control signal of the weighting circuit one of a number of antennas is switched to. This switching is audible to an annoying degree. By inserting a threshold arrangement (31, 32) in the detector, by means of a low-pass filter and a rectifier circuit, an instantaneous threshold voltage is generated varying with the frequency swing of the modulating signal. With a large swing, corresponding with a large amplitude of the modulating signal, switching is audible to a less annoying degree. On the other hand, at moments when the modulating signal has a small amplitude, switching may take place more frequently and is less audible because of the small amplitude of the modulating signal. Improved relaibility in detecting multi-path distortion is achieved by also supplying the instantaneous threshold voltage to the AM-detector.
Inventors
- 👤 Franciscus J. A. M. Sessink
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:31
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/08; H04B7/0802; H04B7/0805; H04B7/0814; H04B1/00; H04B1/06; H04B1/10; H04B1/1081
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
168 words
A receiver for angle-modulated signals, coming from one or a plurality of antennas, comprising a diversity switch having a signal input connected to at least one antenna, a signal output and a control input for selecting at the signal output an angle-modulated signal by means of a control signal on the control input, and comprising a multi-path detector coupled to the signal output and connected to the control input for supplying the control signal to the control input when the multi-path detector detects multi-path distortion in the selected signal, the multi-path detector comprising a threshold arrangement coupled to the output of the diversity switch for generating a threshold voltage having an amplitude value depending on the frequency swing of the angle-modulated signal, characterized in that the threshold voltage has an amplitude value instantaneously varying with the frequency swing of the angle-modulated signal, and in that said multi-path detector has a sensitivity the variation of which instantaneously corresponds to the variation of the amplitude value of the threshold voltage.
Claim 2
Dependent Claim
168 words
A receiver for angle-modulated signals, coming from one or a plurality of antennas, comprising a diversity switch having a signal input connected to at least one antenna, a signal output and a control input for selecting at the signal output an angle-modulated signal by means of a control signal on the control input, and comprising a multi-path detector coupled to the signal output and connected to the control input for supplying the control signal to the control input when the multi-path detector detects multi-path distortion in the selected signal, the multi-path detector comprising a threshold arrangement coupled to the output of the diversity switch for generating a threshold voltage having an amplitude value depending on the frequency swing of the angle-modulated signal, characterized in that the threshold voltage has an amplitude value instantaneously varying with the frequency swing of the angle-modulated signal, and in that said multi-path detector has a sensitivity the variation of which instantaneously corresponds to the variation of the amplitude value of the threshold voltage.
Claim 3
Dependent Claim
87 words
A receiver as claimed in claim 1, in which the multi-path detector comprises a comparator circuit having two inputs, of which a first input is designed for supplying a signal which depends on the extend of multi-path distortion in the selected angle-modulated signal, characterized in that the threshold arrangement is composed of a series arrangement coupled to the intermediate frequency section of the receiver, this series arrangement comprising a low-pass filter and a rectifier circuit and an output connected to the second input of the comparator circuit.
Claim 4
Dependent Claim
38 words
A receiver as claimed in claim 2, wherein the multi-path detector comprises a frequency noise peak detector, characterized in that the output of the frequency noise peak detector is connected to the first input of the comparator circuit.
Claim 5
Dependent Claim
32 words
A receiver as claimed in claim 2, wherein the multi-path detector comprises an AM-detector, characterized in that the output of the AM-detector is connected to the first input of the comparator circuit.
Claim 6
Dependent Claim
143 words
A multi-path detector for use in a receiver for angle-modulated signals comprising a diversity switch having a signal input connected to at least one antenna, a signal output and a control input for selecting at the signal output an angle-modulated signal by means of a control signal on the control input, said multi-path detector being coupled to the signal output and connected to the control input for supplying the control signal to the control input when said multi-path detector detects multi-path distortion in the selected signal, said multi-path detector comprising a threshold arrangement coupled to the output of the diversity switch for generating a threshold voltage having an amplitude value depending on the frequency swing of the angle modulated signal, and said multi-path detector having a sensitivity the variation of which corresponds to the variation of the amplitude value of the threshold voltage.
Claim 7
Dependent Claim
143 words
A multi-path detector for use in a receiver for angle-modulated signals comprising a diversity switch having a signal input connected to at least one antenna, a signal output and a control input for selecting at the signal output an angle-modulated signal by means of a control signal on the control input, said multi-path detector being coupled to the signal output and connected to the control input for supplying the control signal to the control input when said multi-path detector detects multi-path distortion in the selected signal, said multi-path detector comprising a threshold arrangement coupled to the output of the diversity switch for generating a threshold voltage having an amplitude value depending on the frequency swing of the angle modulated signal, and said multi-path detector having a sensitivity the variation of which corresponds to the variation of the amplitude value of the threshold voltage.
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) | 1992-10-30 | 1993-05-01 | 1993-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-30 | 1997-05-01 | 1997-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-30 | 2001-05-01 | 2001-10-31 | $7700.00 | Window Closed / Lapsed |