Battery-powered transmitter including current control circuit
AssigneeGTE Products Corporation
InventorColin B. Weir
Life of this patent
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Abstract
A portable, battery powered transmitter including a current control circuit for controlling the output power of the transmitter over a wide range of variations in battery voltage, rf input power and frequency, and ambient temperature. The transmitter includes an amplifier operative to receive a voltage from the current control circuit and to draw load current from the current control circuit. The load current drawn by the amplifier is limited by the current control circuit to a predetermined maximum value thereby to prolong the mission life of the battery source powering the transmitter.
Claims14
A transmitter powered by a dc voltage of a battery source and arranged to amplify a rf signal over a range of variations in the value of the voltage of the battery source, said transmitter comprising:
- amplifier means arranged to receive said rf signal and having a control input;
- control circuit means coupled to the battery source and to the control input of the amplifier means and powered by the battery source;
- said control circuit means being operative to produce a control voltage at the control input of the amplifier means and said amplifier means being operative in response to said control voltage to draw load current from the control circuit means having a value related to the value of the control voltage and to amplify the rf signal received thereby in accordance with the value of the control voltage;
- said control circuit means comprising:
- sensing circuit means operative to sense the value of load current drawn by the amplifier means and to produce a voltage related thereto;
- and
- control means operative to compare the voltage produced by the sensing circuit means with a voltage varying with variations in the voltage of the battery source and to produce a control voltage related to the difference at the control input of the amplifier means, said control voltage having a value such that the load current drawn by the amplifier means does not exceed a specified maximum value, thereby conserving the battery source.
A transmitter powered by a dc voltage of a battery source and arranged to amplify a rf signal over a range of variations in the frequency and/or power level of the rf signal and over a range of variations in the value of the voltage of the battery source, said transmitter comprising:
- rf input source means powered by the battery source and operative to produce a rf signal of a predetermined frequency;
- amplifier means arranged to receive said rf signal and having a control input;
- control circuit means coupled to the battery source and to the control input of the amplifier means and powered by the battery source, said control circuit means being operative to produce a control voltage at the control input of the amplifier means having a value related to the frequency and power level of the rf signal and to the value of voltage of the battery source and further operative to produce a related load current limited to a predetermined maximum value, and said amplifier means being operative in response to said control voltage to amplify the rf signal in accordance with the value of the control voltage and to draw load current from the control circuit means having a value related to the value of the control voltage but not to exceed the predetermined maximum value;
- said control circuit means comprising:
- sensing circuit means operative to sense the value of load current drawn by the amplifier means and to produce a voltage related thereto;
- and
- control means operative to compare the voltage produced by the sensing circuit means with a voltage varying with variations in the voltage of the battery source and to produce a control voltage related to the difference at the control input of the amplifier means, said control voltage having a value such that the load current drawn by the amplifier means does not exceed the specified maximum value, thereby conserving the battery source.
Dependencies are inferred from the claim text.