US4595795A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic sensitivity switching circuit for a cordless telephone
Assignee: Uniden Corp
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Filing: 1984-07-18
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Granted: 1986-06-17
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Expires: 2004-07-18
Abstract
Abstract An automatically switching circuit for the receiving sensitivity in a cordless telephone comprises a base unit and a portable handset in wireless communication with the base unit, which is responsive to the flow of charging current from the base unit to the portable handset for reducing the gain of an antenna or amplifying stage to a desired low level, thereby preventing erroneous ringing due to surrounding noise signals or disturbances while the portable handset rests on the base unit.
Inventors
- 👤 Hiroshi Endo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:09
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/72; H04M1/724
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
133 words
An automatic sensitivity switching circuit for use in a cordless telephone comprising a base unit and a portable handset in wireless connection with the base unit, said portable handset including a charging circuit which has a secondary battery, and is responsive to the placement of the handset on the base unit for charging the secondary battery, a call signal amplifying circuit which is adapted to receive signals from the base unit by means of an antenna and supplied with electric power from the secondary battery in said charging circuit, which automatic sensitivity switching circuit comprises a switching element for turning itself on in response to a charging current fed from the base unit to the secondary battery of the handset so as to substantially lower the sensitivity of the call signal amplifying circuit.
Claim 2
Dependent Claim
133 words
An automatic sensitivity switching circuit for use in a cordless telephone comprising a base unit and a portable handset in wireless connection with the base unit, said portable handset including a charging circuit which has a secondary battery, and is responsive to the placement of the handset on the base unit for charging the secondary battery, a call signal amplifying circuit which is adapted to receive signals from the base unit by means of an antenna and supplied with electric power from the secondary battery in said charging circuit, which automatic sensitivity switching circuit comprises a switching element for turning itself on in response to a charging current fed from the base unit to the secondary battery of the handset so as to substantially lower the sensitivity of the call signal amplifying circuit.
Claim 3
Dependent Claim
35 words
An automatic sensitivity switching circuit according to claim 1 wherein the antenna circuit is supplied with a part of the charging current flowing into said secondary battery when the switching element is operated to close.
Claim 4
Dependent Claim
16 words
An automatic sensitivity switching circuit according to claim 2 wherein the switching element comprises a diode.
Claim 5
Dependent Claim
47 words
An automatic sensitivity switching circuit according to claim 1 wherein the call signal amplifying circuit is supplied with a part of the charging current flowing into said secondary battery when the switching element is operated to reduce the gain of the amplifier to a desired low level.
Claim 6
Dependent Claim
48 words
An automatic sensitivity switching circuit according to claim 4 wherein a selected transistor in the call signal amplifying circuit is supplied with a part of the charging current flowing into said secondary battery when the switching element is operated for depriving the selected transistory of its amplifying function.
Claim 7
Dependent Claim
39 words
An automatic sensitivity switching circuit according to claim 1 wherein a resonance coil in the call signal amplifying circuit is supplied with a part of the charging current flowing into said secondary battery when the switching element is operated.
References Cited (Backward Citations)
US4511761A
Cited
US4511761B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-16 | 1989-12-16 | 1990-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-16 | 1993-12-16 | 1994-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-16 | 1997-12-16 | 1998-06-17 | $7700.00 | Window Closed / Lapsed |