Automatic output power controller
First Claim
1. An automatic output power controller wherein gain adjustment of a power amplifier is performed automatically so that the output of the power amplifier amplifying signals modulated by base band signals is held constant, said controller comprising:
- an output power detector for detecting the output power of said power amplifier and outputting a voltage in response to the output power so detected;
a sample-and-hold circuit for sampling said voltage in response to the output power detected by said output power detector at selected time intervals and for holding the sampled voltage which is sampled at each time interval to a next sample point at a next time interval;
a voltage difference output means for comparing the voltage sampled-and-held in said sample-and-hold circuit with a selected reference voltage and for outputting the voltage difference between said sampled-and-held voltage and said selected reference voltage;
a low pass filter for smoothing the voltage difference obtained in said voltage difference output means and outputting a feedback control signal which is a function of the smoothed voltage difference;
an output power adjusting means for adjusting the output power in response to the feedback control signal output by said low pass filter; and
an equi-output point extraction means for extracting timing at which the output power becomes a constant value based on a phase signal set by a switch group and for outputting the extracted timing as a sample timing signal for determining said selected time intervals of said sample-and-hold circuit.
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Accused Products
Abstract
An automatic output power controller controls signals output by an amplifier amplifying a modulated wave with its envelope varying due to the modulation so that the mean power becomes constant. An equi-output point extraction circuit extracts timing of the output power of the amplifier becoming a constant value from a base band signal or the like, and supplies the timing to a sample-and-hold circuit. The sample-and-hold circuit samples and holds the output power. Difference between the sample-and-hold value and the reference value is supplied to an output power adjusting circuit, and the output power adjusting circuit controls signals output by the amplifier in accordance with the difference so that the mean power becomes constant.
37 Citations
9 Claims
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1. An automatic output power controller wherein gain adjustment of a power amplifier is performed automatically so that the output of the power amplifier amplifying signals modulated by base band signals is held constant, said controller comprising:
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an output power detector for detecting the output power of said power amplifier and outputting a voltage in response to the output power so detected; a sample-and-hold circuit for sampling said voltage in response to the output power detected by said output power detector at selected time intervals and for holding the sampled voltage which is sampled at each time interval to a next sample point at a next time interval; a voltage difference output means for comparing the voltage sampled-and-held in said sample-and-hold circuit with a selected reference voltage and for outputting the voltage difference between said sampled-and-held voltage and said selected reference voltage; a low pass filter for smoothing the voltage difference obtained in said voltage difference output means and outputting a feedback control signal which is a function of the smoothed voltage difference; an output power adjusting means for adjusting the output power in response to the feedback control signal output by said low pass filter; and an equi-output point extraction means for extracting timing at which the output power becomes a constant value based on a phase signal set by a switch group and for outputting the extracted timing as a sample timing signal for determining said selected time intervals of said sample-and-hold circuit. - View Dependent Claims (2, 3, 4)
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5. An automatic output power controller wherein gain adjustment of a power amplifier is performed automatically so that the output of the power amplifier amplifying signals modulated by base band signals is held constant, said controller comprising:
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an output power detector for detecting the output power of said power amplifier and outputting a voltage in response to the output power so detected; a sample-and-hold circuit for sampling said voltage in response to the output power detected by said output power detector at selected time intervals and for holding the sampled voltage which is sampled at each time interval to a next sample point at a next time interval; a voltage difference output means for comparing the voltage sampled-and-held in said sample-and-hold circuit with a selected reference voltage and for outputting the voltage difference between said sampled-and-held voltage and said selected reference voltage; a low pass filter for smoothing the voltage difference obtained in said voltage difference output means and outputting a feedback control signal which is a function of the smoothed voltage difference; an output power adjusting means for adjusting the output power in response to the feedback control signal outputted by said low pass filter; and an equi-output point extraction means for extracting the timing at which output power becomes a constant value from the base band signal and for outputting the extracted timing as a sample timing signal for determining said selected time intervals of said sample-and-hold circuit. - View Dependent Claims (6, 7, 8, 9)
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Specification