System for improving the dynamic range of transmitter power measurement in a cellular telephone
First Claim
1. In a mobile station having a transmitter including a transmitter variable gain amplifier developing an RF output signal applied to an antenna, an improved power output control circuit comprising:
- a detector circuit for rectifying an input signal to produce a DC output representing power level of the input signal;
a sampling circuit connected to the transmitter and the detector circuit for alternately connecting and disconnecting the RF signal from the transmitter to the detector circuit, whereby the detector circuit develops an alternating DC output signal;
a variable gain AC amplifier coupled to the detector circuit for amplifying the detector output;
a gain control circuit coupled to the AC amplifier for receiving the amplified detector output and comparing it to a select reference to develop a feedback signal used to vary gain of the AC amplifier to maintain a desired constant output level, the feedback signal representing transmitter output power; and
a comparator for comparing the feedback signal to a control reference to control gain of the transmitter variable gain amplifier.
1 Assignment
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Accused Products
Abstract
An improved power output control circuit is used in a mobile station having a transmitter including a transmitter variable gain amplifier developing an RF output signal applied to an antenna. The improved power output control circuit includes a detector circuit for rectifying an input signal to produce a DC output representing power level of the input signal. A sampling circuit is connected to the transmitter and the detector circuit for alternately connecting and disconnecting the RF signal from the transmitter to the detector circuit, whereby the detector circuit develops an alternating DC output signal. A variable gain AC amplifier is coupled to the detector circuit for amplifying the detector output. A gain control circuit is coupled to the AC amplifier for receiving the amplified detector output and comparing it to a select reference to develop a feedback signal used to vary gain of the AC amplifier to maintain a desired constant output level, the feedback signal representing transmitter output power. A comparator compares the feedback signal to a control reference to control gain of the transmitter variable gain amplifier.
133 Citations
20 Claims
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1. In a mobile station having a transmitter including a transmitter variable gain amplifier developing an RF output signal applied to an antenna, an improved power output control circuit comprising:
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a detector circuit for rectifying an input signal to produce a DC output representing power level of the input signal; a sampling circuit connected to the transmitter and the detector circuit for alternately connecting and disconnecting the RF signal from the transmitter to the detector circuit, whereby the detector circuit develops an alternating DC output signal; a variable gain AC amplifier coupled to the detector circuit for amplifying the detector output; a gain control circuit coupled to the AC amplifier for receiving the amplified detector output and comparing it to a select reference to develop a feedback signal used to vary gain of the AC amplifier to maintain a desired constant output level, the feedback signal representing transmitter output power; and a comparator for comparing the feedback signal to a control reference to control gain of the transmitter variable gain amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of controlling output power in a mobile station having a transmitter including a transmitter variable gain amplifier developing an RF output signal applied to an antenna, comprising the steps of:
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alternately operating a switch to connect and disconnect the RF signal from the transmitter to a voltage detector for developing an alternating DC output signal; amplifying the alternating DC output signal; comparing the amplified alternating DC signal to a select reference to develop a feedback value, the feedback value representing transmitter output power; varying gain of the amplified alternating DC signal based on the feedback value to maintain a desired fixed amplified alternating DC signal; and controlling gain of the transmitter variable gain amplifier using the feedback value. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification