US4989260A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transmitter with power reduction to compensate for varying radiated electric field strength when switching between batteries and AC power
Assignee: Fisher Price Inc
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Filing: 1989-05-17
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Granted: 1991-01-29
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Expires: 2009-05-17
Abstract
Abstract A radio frequency transmitter of the type that is adapted to be powered from an internal battery power source, or from an external power supply that is connected to the transmitter by an electrical conductor, which conductor acts as a part of the antenna system for such transmitter and increases the strength of the signal radiated by the transmitter when the transmitter is powered from the external power supply, and which includes a circuit for reducing the power output of the transmitter, when the transmitter is connected to the external power supply.
Inventors
- 👤 James P. Meade
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:17
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/10; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/1607; H04B1/02; H04B1/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
81 words
In a radio transmitter of the type that is powered in the alternative from an internal power source or an external power source connected to the transmitter by an electrical conductor, and in which radiation by said electrical conductor increases the strength of the signal broadcast by the transmitter when the transmitter is powered from the external power source, the improvement comprising: means for reducing the power output of the transmitter when the transmitter is connected to the external power source.
Claim 2
Dependent Claim
81 words
In a radio transmitter of the type that is powered in the alternative from an internal power source or an external power source connected to the transmitter by an electrical conductor, and in which radiation by said electrical conductor increases the strength of the signal broadcast by the transmitter when the transmitter is powered from the external power source, the improvement comprising: means for reducing the power output of the transmitter when the transmitter is connected to the external power source.
Claim 3
Dependent Claim
60 words
The transmitter of claim 1 comprising a modulated oscillator, a drive-amplifier coupled to the modulated oscillator, and a power amplifier coupled to the driver amplifier, in which said means for reducing the power output of the transmitter comprises switchable means coupled between said modulated oscillator and said driver-amplifier for reducing the amplitude of the signal applied to said modulated oscillator.
Claim 4
Dependent Claim
35 words
The radio transmitter of claim 1 wherein said means for reducing the power output of said transmitter comprises means for switchably connecting an impedance from a radio frequency signal path in said transmitter to ground.
Claim 5
Dependent Claim
38 words
The radio transmitter of claim 3 wherein said switchable means comprises a switching transistor having an input connected to the output of said external power source for turning on said transistor when said external power source is connected.
Claim 6
Dependent Claim
25 words
The radio transmitter of claim 3 wherein said means for reducing the power output comprises a switch means activated by connection of said electrical conductor.
Claim 7
Dependent Claim
120 words
A low power radio frequency transmitter comprising: a modulated oscillator having an output; a microphone connected to said modulated oscillator; a driver-amplifier connected to said modulated oscillator by a coupling capacitor; a power amplifier connected to said driver-amplifier; impedance means switchably connected to the input of said driver-amplifier for shunting a portion of said input to ground; internal battery power supplying means connected to the modulated oscillator, driver amplifier and power amplifier; connector means coupled to the modulated oscillator, driver amplifier and power amplifier, and adapted to be connected to an external power source through a cable; and means coupled to the connector means responsive to the connection of said external power source for connecting said impedance means to ground.
Claim 8
Dependent Claim
120 words
A low power radio frequency transmitter comprising: a modulated oscillator having an output; a microphone connected to said modulated oscillator; a driver-amplifier connected to said modulated oscillator by a coupling capacitor; a power amplifier connected to said driver-amplifier; impedance means switchably connected to the input of said driver-amplifier for shunting a portion of said input to ground; internal battery power supplying means connected to the modulated oscillator, driver amplifier and power amplifier; connector means coupled to the modulated oscillator, driver amplifier and power amplifier, and adapted to be connected to an external power source through a cable; and means coupled to the connector means responsive to the connection of said external power source for connecting said impedance means to ground.
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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) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |