EP0261967A2
Expired / Lapsed
EP
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Automatic electrical power control circuit
Assignee: NEC Corp
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Filing: 1987-09-24
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Granted: —
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Expires: 2007-09-24
Abstract
Abstract A power control circuit comprises a signal input (1), a controllable attenuator (2), an amplifier (3), an output (5), a power detector (4), a reference circuit, a comparator (6), an external control input (7), an error detector (8), and a controller (9). The comparator (6), error detector (8), and controller (9) are digital circuits realized by a microprocessor. The attenuator (2) is between the signal input (1) and the input (3A) to the amplifier (3) to regulate the amplifier's output (3b). The power detector (3) couples to the amplifier output to generate a measurement signal representing the power at the output. The reference circuit generates a reference signal representing a predetermined minimum output when the signal input is nonzero. The comparator (6) compares the measurement and reference signals and generates a decision signal (6b) indicating if the signal input is nonzero. The external control input (7) receives an external control signal. The error detector (8) is coupled to the power detector (4) and the external control input (7) and computes the difference between the external control signal and the measurement signal. When the measurement signal is at or above the minimum power, the controller (9) provides an integral of the computed difference to control the variable attenuator (2). When the measurement signal is below the minimum power, the controller (9) keeps the attenuator at a prior constant value.
Inventors
- 👤 Toshinori C/O Nec Corporation Hotta
- 👤 Osamu C/O Nec Corporation Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 07:25
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3036; H03G3/3042; H03G3/3047
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
202 words
An automatic power control circuit comprising: variable attenuator means disposed ahead of a power amplifier for variably setting the amount of attenuation of an input signal for the power amplifier; power detection means for detecting a portion of the output from the power amplifier and for generating a power output signal corresponding to the power output level of the power amplifier; comparison means for comparing the magnitude of the power output signal against a predetermined threshold value and for generating a decision signal based on said comparison indicating the presence or absence of power output from the power amplifier; error detection means for detecting the difference between control data from an external power output control signal and the power output signal from the detection means and generating an error signal corresponding to said difference; attenuator control means for integrating the error signal and generating an integrated correction value when the decision signal indicates the presence of power output from the power amplifier, and for generating the most recent prior integrated correction value when the decision signal indicates the absence of power output from the power amplifier; and means for transmitting said integrated correction value as a control signal to the variable attenuator.
Claim 2
Dependent Claim
202 words
An automatic power control circuit comprising: variable attenuator means disposed ahead of a power amplifier for variably setting the amount of attenuation of an input signal for the power amplifier; power detection means for detecting a portion of the output from the power amplifier and for generating a power output signal corresponding to the power output level of the power amplifier; comparison means for comparing the magnitude of the power output signal against a predetermined threshold value and for generating a decision signal based on said comparison indicating the presence or absence of power output from the power amplifier; error detection means for detecting the difference between control data from an external power output control signal and the power output signal from the detection means and generating an error signal corresponding to said difference; attenuator control means for integrating the error signal and generating an integrated correction value when the decision signal indicates the presence of power output from the power amplifier, and for generating the most recent prior integrated correction value when the decision signal indicates the absence of power output from the power amplifier; and means for transmitting said integrated correction value as a control signal to the variable attenuator.
Claim 3
Dependent Claim
60 words
The automatic power control circuit of claim 1 wherein power detection means outputs the power output signal as digital data, the control data derived by the error detection means from the external power output control signal is digital control data and the error signal it generates is a digital signal, and the attenuator control means digitally integrates the error signal.
Claim 4
Dependent Claim
28 words
The automatic power control circuit of claim 1 wherein the comparison means, error detection means, and attenuator control means include a common microprocessor means for performing their functions.
Claim 5
Dependent Claim
219 words
A power control circuit comprising: an amplifying transmission path having an input for a communication signal, an output for an amplified version of the communication signal, an external control input for an external power control signal, and a controllable variable attenuation means in the amplifying transmission path for regulating the power of the amplified communication signal; reference means for generating a first signal representing a predetermined minimum power at the output when the communication signal fed to the input is nonzero, and detector means coupled to the transmission path for generating a second signal representing the actual power at the output, and comparison means responsive to the first and second signals for indicating their relative size by generating a third signal; error means coupled to the power detector and the external control input and responsive to the second signal and the external power control signal for generating a fourth signal proportional to their difference; and controller means responsive to the third and fourth signals for generating a fifth signal for negative feedback control of the variable attenuator means, the fifth signal being proportional to the integral of the fourth signal only when the third signal indicates that the second signal is equal to or greater than the first signal, and otherwise being held constant at its most recent value.
Claim 6
Dependent Claim
219 words
A power control circuit comprising: an amplifying transmission path having an input for a communication signal, an output for an amplified version of the communication signal, an external control input for an external power control signal, and a controllable variable attenuation means in the amplifying transmission path for regulating the power of the amplified communication signal; reference means for generating a first signal representing a predetermined minimum power at the output when the communication signal fed to the input is nonzero, and detector means coupled to the transmission path for generating a second signal representing the actual power at the output, and comparison means responsive to the first and second signals for indicating their relative size by generating a third signal; error means coupled to the power detector and the external control input and responsive to the second signal and the external power control signal for generating a fourth signal proportional to their difference; and controller means responsive to the third and fourth signals for generating a fifth signal for negative feedback control of the variable attenuator means, the fifth signal being proportional to the integral of the fourth signal only when the third signal indicates that the second signal is equal to or greater than the first signal, and otherwise being held constant at its most recent value.
Claim 7
Dependent Claim
33 words
The power control circuit of claim 5 wherein the amplifying transmission path includes a power amplifier and the controllable variable attenuation means is disposed in the transmission path ahead of the power amplifier.
Claim 8
Dependent Claim
28 words
The power control circuit of claim 5 wherein the first, second, and third signals respectively generated by the reference means, detector means, and comparison means are digital signals.
Claim 9
Dependent Claim
48 words
The power control circuit of claim 6 wherein the fourth and fifth signals respectively generated by the error means and controller means are also digital signals, and the controller means includes means for converting the fifth signal to an analog signal for feedback to the variable attenuator means.
Claim 10
Dependent Claim
25 words
The power control circuit of claim 6 wherein the reference means, detector means, and comparison means include a common microprocessor means for performing their functions.
Claim 11
Dependent Claim
28 words
The power control circuit of claim 7 wherein the reference means, detector means, comparison means, error means, and controller means include a common microprocessor for performing their functions.
Claim 12
Dependent Claim
155 words
A power control circuit comprising variable attenuation means in a transmission path extending from an input terminal to an output terminal for controlling the transmission power level within the transmission path; means responsive to the variable attenuation means and coupled to the transmission path for generating a first digital signal which is representative of the transmission power level within the transmission path; means for generating a second digital signal which represents a desired transmission power level for the transmission path; comparison means for comparing the first and second digital signals to determine whether the transmission power level is at, above, or below a desired minimum level; and control means responsive to the comparison means for adjusting the level of the variable attenuator means in order to maintain the desired transmission power level in the transmission path only when the comparison means determines that the transmission power level is at or above said desired minimum level.
Claim 13
Dependent Claim
155 words
A power control circuit comprising variable attenuation means in a transmission path extending from an input terminal to an output terminal for controlling the transmission power level within the transmission path; means responsive to the variable attenuation means and coupled to the transmission path for generating a first digital signal which is representative of the transmission power level within the transmission path; means for generating a second digital signal which represents a desired transmission power level for the transmission path; comparison means for comparing the first and second digital signals to determine whether the transmission power level is at, above, or below a desired minimum level; and control means responsive to the comparison means for adjusting the level of the variable attenuator means in order to maintain the desired transmission power level in the transmission path only when the comparison means determines that the transmission power level is at or above said desired minimum level.
Claim 14
Dependent Claim
52 words
The power control means of claim 10 wherein the comparator means further comprises a preset digital value representing a desired minimum transmission power level, and means for giving either a "YES" or a "NO" decision signal depending upon the value of the first digital signal, as compared to the pre-set digital value.
Claim 15
Dependent Claim
54 words
The power control means of claim 11 and means in said control means responsive to a "Yes" signal for forwarding an existing level control signal to said variable attenuation means, said means in said control means responsive to a "No" signal for forwarding an increase transmission power level control signal to said variable attenuator.
Claim 16
Dependent Claim
34 words
The power control means of claim 12 and adder means for adding said transmission power control signal to said decision signal to generate the transmission power control signal forwarded to said variable attenuator means.
Claim 17
Dependent Claim
22 words
The control means of claim 13 wherein signals transmitted over said transmission path are packet signals transmitted in a satellite communication system.
Claim 18
Dependent Claim
23 words
The control means of claim 10 including microprocessor means for digitally performing the functions of the reference means, comparison means and control means.
References Cited (Backward Citations)
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