Patent US3748495A successfully refreshed from Google Patents.
US3748495A
Expired / Lapsed
US
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Beacon marker interrupt device
Assignee: NARCO AVIONICS Inc 270 COMMERCE DRIVE FORT WASHINGTON PA A CORP OF
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Filing: 1971-12-06
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Granted: 1973-07-24
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Expires: 1991-12-06
Abstract
Abstract Apparatus for providing adjustable time-limited attenuation of a marker beacon receiver audio signal, comprising a variable attentuator connected between the audio signal source and the audio signal output, and shunted by a normally closed timer switch. An adjustable RC timing circuit, actuated by an automatic or manually operable mute switch, drives a two state amplifier, the output of which is connected to and operates the timer switch.
Inventors
- 👤 N Messinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:41
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H03G3/301; H03G3/3015
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
230 words
Apparatus for timed interruption of a marker beacon audio signal, comprising: a. attenuator means, connected in the path of said audio signal, and having switchable attenuating and non-attenuating states and an input for receiving a switching signal; b. switching signal means, for switching said attenuator means into one of said states, having an output connected to said input of said attenuator means, and having first and second input terminals, the output of said switching signal means switching said attenuator means to a first low attenuation state when the signal connected to said first input terminal is greater than the signal connected to said second input terminal, and driving said attenuator means to a second high attenuation state when the signal connected to the second input terminal is greater than the signal connected to the first input terminal, c. timing means, connected to said first and second inputs, and adapted to provide a time varying signal to one of said inputs, and a constant signal to the other of said inputs said constant signal being such that said switching means normally maintains said attenuator means in its low attenuation state, and d. switch means, connected to said timing means for triggering said timing means through a timing cycle, whereby said switching circuit means switches said attenuator means into said attenuating state, causing attenuation of said audio signal during such timing cycle.
Claim 2
Dependent Claim
230 words
Apparatus for timed interruption of a marker beacon audio signal, comprising: a. attenuator means, connected in the path of said audio signal, and having switchable attenuating and non-attenuating states and an input for receiving a switching signal; b. switching signal means, for switching said attenuator means into one of said states, having an output connected to said input of said attenuator means, and having first and second input terminals, the output of said switching signal means switching said attenuator means to a first low attenuation state when the signal connected to said first input terminal is greater than the signal connected to said second input terminal, and driving said attenuator means to a second high attenuation state when the signal connected to the second input terminal is greater than the signal connected to the first input terminal, c. timing means, connected to said first and second inputs, and adapted to provide a time varying signal to one of said inputs, and a constant signal to the other of said inputs said constant signal being such that said switching means normally maintains said attenuator means in its low attenuation state, and d. switch means, connected to said timing means for triggering said timing means through a timing cycle, whereby said switching circuit means switches said attenuator means into said attenuating state, causing attenuation of said audio signal during such timing cycle.
Claim 3
Dependent Claim
20 words
The apparatus as described in claim 1, wherein said attenuaTor means comprises a variable resistor shunted by a semiconductor switch.
Claim 4
Dependent Claim
16 words
The apparatus as described in claim 2, wherein said semiconductor switch is an enhancement mode FET.
Claim 5
Dependent Claim
16 words
The apparatus as described in claim 1, wherein said switching signal means comprises a comparator amplifier.
Claim 6
Dependent Claim
19 words
The apparatus as described in claim 1, wherein said timing means comprises an RC circuit, with a variable resistor.
Claim 7
Dependent Claim
32 words
The apparatus as described in claim 1, wherein said timing means includes a divider circuit for determining the relative amplitudes of the signals connected to said first and second input terminals respectively.
Claim 8
Independent Claim
86 words
A method for providing a timed interruption of a detected marker beacon audio signal in an aircraft, comprising: a. detecting the approximate peak of said audio signal, corresponding to the point where said aircraft is substantially over the transmitter of said marker beacon; b. attenuating said audio signal by switchably placing an attenuator in the electrical path of said detected audio signal; c. automatically maintaining said attenuator in said path for a predetermined time; and d. automatically removing said attenuator after said predetermined period is timed.
Claim 9
Independent Claim
86 words
A method for providing a timed interruption of a detected marker beacon audio signal in an aircraft, comprising: a. detecting the approximate peak of said audio signal, corresponding to the point where said aircraft is substantially over the transmitter of said marker beacon; b. attenuating said audio signal by switchably placing an attenuator in the electrical path of said detected audio signal; c. automatically maintaining said attenuator in said path for a predetermined time; and d. automatically removing said attenuator after said predetermined period is timed.
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) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |