US3750057A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switchable band pass-band reject filter apparatus
Assignee: NARCO AVIONICS Inc 270 COMMERCE DRIVE FORT WASHINGTON PA A CORP OF
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Filing: 1972-01-31
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Granted: 1973-07-31
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Expires: 1992-01-31
Abstract
Abstract A frequency selective circuit switchable to provide alternately a band reject or band pass response, comprising a filter circuit connected to a double pole double throw switch so that in a first position a frequency band is attenuated while frequencies above and below the center of the band are passed, and in a second position a band about the same center is passed with a sharp drop-off in response both above and below the passband.
Inventors
- 👤 J Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:25
CPC Classifications
H; H01; H01H; H01H47/00; H01H47/02; H01H47/20; H03; H03H; H03H7/00; H03H7/01; H03H7/06; H03H7/07
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
A switchable filter circuit, for providing a band rejection response and a band pass response, comprising: a. a frequency selective circuit, having an input terminal and an output terminal, which frequency selective circuit has a band reject characteristic; b. a double pole double throw switch, having a pair of input terminals connected to said frequency selective circuit input and output terminals respectively; c. an audio input terminal connected to said frequency selective circuit input terminal, and an audio output terminal; and d. when said switch is in a first position said frequency selective circuit output terminal is connected to said audio output terminal, and when said switch is in said second position said frequency selective circuit output terminal is connected to a ground reference and said frequency selective circuit input terminal is connected to said audio output terminal.
Claim 2
Dependent Claim
138 words
A switchable filter circuit, for providing a band rejection response and a band pass response, comprising: a. a frequency selective circuit, having an input terminal and an output terminal, which frequency selective circuit has a band reject characteristic; b. a double pole double throw switch, having a pair of input terminals connected to said frequency selective circuit input and output terminals respectively; c. an audio input terminal connected to said frequency selective circuit input terminal, and an audio output terminal; and d. when said switch is in a first position said frequency selective circuit output terminal is connected to said audio output terminal, and when said switch is in said second position said frequency selective circuit output terminal is connected to a ground reference and said frequency selective circuit input terminal is connected to said audio output terminal.
Claim 3
Dependent Claim
118 words
A switchable frequency selective circuit, for providing a band rejection response and a band pass response, comprising: a. a band rejection frequency selective circuit having an input and an output; b. an input terminal connected to said frequency selective circuit input, and an output terminal; c. switch means, connected to said frequency selective circuit, and having a first position where said switch means connects said frequency selective circuit to said output terminal such that the overall circuit response is that of the frequency selective circuit, and a second position wherein said switch means connects said output of sAid frequency selective circuit to a ground reference so as to provide a band pass response with a high frequency roll-off.
Claim 4
Dependent Claim
118 words
A switchable frequency selective circuit, for providing a band rejection response and a band pass response, comprising: a. a band rejection frequency selective circuit having an input and an output; b. an input terminal connected to said frequency selective circuit input, and an output terminal; c. switch means, connected to said frequency selective circuit, and having a first position where said switch means connects said frequency selective circuit to said output terminal such that the overall circuit response is that of the frequency selective circuit, and a second position wherein said switch means connects said output of sAid frequency selective circuit to a ground reference so as to provide a band pass response with a high frequency roll-off.
Claim 5
Dependent Claim
18 words
The apparatus as described in claim 2, wherein said switch means is a double pole double throw switch.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |