US4742570A
Expired / Lapsed
US
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Multipath noise detecting circuit
Assignee: ALPHINE ELECTRONICS Inc A CORP OF JAPAN
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Filing: 1986-08-25
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Granted: 1988-05-03
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Expires: 2006-08-25
Abstract
Abstract A multipath noise detecting circuit, which is not affected by ignition noise nor by the level of the antenna input voltage, includes a band pass filter having a mean frequency of 114 KH supplied with signals output from a FM demodulator, an AM detector for subjecting the signal input from said band pass filter to AM-detection, and a detector section for detecting as multipath noise the pulses included in the signal output from said AM-detector.
Inventors
- 👤 Nobuo Ichikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:43
CPC Classifications
H; H04; H04H; H04H40/00; H04H40/18; H04H40/27; H04H40/36; H04H40/45; H04H40/72; H04B; H04B1/00; H04B1/06; H04B1/10; H04B1/1027; H04B1/16; H04B1/1646; H04B1/1661
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
109 words
A multipath noise detecting circuit for detecting multipath noise pulses directly from a signal output of a FM signal demodulator, comprising: a band pass filter receiving the signal output of the FM signal demodulator having a mean frequency of three times a subcarrier frequency of the FM signal for outputting a third harmonic component signal of said FM signal; an AM detector receiving the third harmonic component output of said band pass filter for detecting and outputting an amplitude detection signal; and a detector section receiving the amplitude detection signal from said AM detector for detecting multipath noise pulses included therein and outputting a multipath noise detection signal therefrom.
Claim 2
Dependent Claim
109 words
A multipath noise detecting circuit for detecting multipath noise pulses directly from a signal output of a FM signal demodulator, comprising: a band pass filter receiving the signal output of the FM signal demodulator having a mean frequency of three times a subcarrier frequency of the FM signal for outputting a third harmonic component signal of said FM signal; an AM detector receiving the third harmonic component output of said band pass filter for detecting and outputting an amplitude detection signal; and a detector section receiving the amplitude detection signal from said AM detector for detecting multipath noise pulses included therein and outputting a multipath noise detection signal therefrom.
Claim 3
Dependent Claim
48 words
A multipath noise detecting circuit according to claim 1, wherein said detector section includes a peak hold circuit and a comparator, forming an automatically-following comparator circuit, for receiving the amplitude detection signal from said AM detector and outputting a pulse detection signal representing a detected mulipath noise pulse.
Claim 4
Dependent Claim
47 words
A multipath noise detecting circuit according to claim 2, wherein said detector section includes a counter circuit for counting pulse detection signals output from said automatically-following comparator circuit and for outputting the multipath noise detection signal when a predetermined number of pulse detection signals have been counted.
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) | 1991-05-03 | 1991-11-02 | 1992-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-03 | 1995-11-02 | 1996-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-03 | 1999-11-02 | 2000-05-03 | $7700.00 | Window Closed / Lapsed |