EP0523718A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Output level control circuit for use in RF transmitter
Assignee: NEC Corp
•
Filing: 1992-07-17
•
Granted: —
•
Expires: 2012-07-17
Abstract
Abstract An output level control circuit for radio-frequency transmitter which intermittently transmits radio-frequency carrier waves such as seen in the TDMA radio communication system and the digital cellular mobile telephone system. The variable gain amplifier unit of this transmitter amplifies the transmitting signal to a predetermined output power level in response to a control signal, the output power level is detected by a detecting diode which receives the application of a temperature-compensated bias voltage, and the sum of the detected output and the bias voltage becomes the detection output to the control loop. The bias voltage of the detecting diode is stored by bias voltage detection means during the off-period of the transmitting signal, an input reference voltage that is supplied in synchronism with the turning-on of the transmitting signal and the stored bias voltage are added by reference signal addition means, and the added output is served as the reference voltage that corresponds to the predetermined output power level. Power control means generates the control signal in response to the added output and the detection output, and the control signal controls the output power level of the variable gain amplifier unit.
Inventors
- 👤 Shinichi C/O Nec Corporation Miyazaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 11:22
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/02; H04B1/04; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3036; H03G3/3042; H03G3/3047; H04B2001/0408; H04B2001/0416
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
132 words
An output level control circuit for use in a radio-frequency transmitter, comprising: variable gain amplifier means for amplifying an intermittently supplied radio-frequency input signal with a gain corresponding to a control signal to proeuce an amplified signal; detector means having a detecting diode biased by a bias voltage, said detector means detecting the power level of said amplified signal to produce a detected voltage, and producing a detector output which is the sum of the detected voltage, said bias voltage and a reference voltage; control means responsive to said detector output for generating said control signal which corresponds to said reference voltage; and reference voltage control means for generating said reference voltage by adding said bias voltage to an input reference voltage supplied in synchronism with the turning-on of said transmitting signal.
Claim 2
Dependent Claim
49 words
An output level control circuit as claimed in claim 1, wherein said detector means comprises signal coupler means for supplying a part of said amplified signal to said detecting diode and bias means for keeping said bias voltage of said detecting diode substantially constant irrespective of the temperature variations.
Claim 3
Dependent Claim
97 words
An output level control circuit as claimed in claim 2, wherein said bias means comprises first, second and third resistors and a compensating diode having an anode connected to a bias voltage supply point via a first resistor and a cathode grounded, and wherein the anode of said detecting diode is connected to said bias voltage supply point via said second resistor and said signal coupler and wherein the cathode of said detecting diode is connected to said third resistor, said bias voltage and the output voltage of said detector means being outputted through said third resistor.
Claim 4
Dependent Claim
47 words
An output level control circuit as claimed in claim 2 or 3, wherein said control means comprises comparator means for comparing said reference voltage and said detector output and power control means for generating said control signal in response to the output voltage of said comparator means.
Claim 5
Dependent Claim
80 words
An output level control circuit as claimed in claim 4, wherein said power control means comprises a first transistor receiving the output of said comparator means at its base and having an emitter grounded; and a second transistor having a base connected to the collector of said first transistor via a resistor and a collector served as the output terminal of said control signal, said emitter of the second transistor being served as the input terminal of a power supply.
Claim 6
Dependent Claim
43 words
An output level control circuit as claimed in claim 5, wherein said variable gain amplifier means comprises a field effect transistor as an amplifier element for said transmitting signal and wherein said control signal controls the drain voltage of said field effect transistor.
Claim 7
Dependent Claim
63 words
An output level control circuit as claimed in any one of claims 1 to 6, wherein said reference voltage control means comprises bias voltage detector means for storing the bias voltage of said detecting diode during the off-period of said transmitting signal and reference voltage addition means for generating said reference voltage by adding said stored bias voltage to said input reference voltage.
Claim 8
Dependent Claim
92 words
An output level control circuit as claimed in any one of claims 1 to 6, wherein said reference voltage control means comprises analog to digital conversion means for converting the output voltage of said detector means into a digital signal; memory means for storing said digital signal; controller means connected to said analog to digital conversion means and said memory means for generating an added output by adding said stored bias voltage to said input reference voltage; and digital to analog conversion means for converting said added output to an analog signal.
Claim 9
Dependent Claim
78 words
An output level control circuit as claimed in any one of claims 1 to 6, wherein said reference voltage control means comprises memory means for storing a bias voltage set in advance of said detecting diode; controller means for generating an added output by adding said stored bias voltage to said input reference voltage; and digital to analog conversion means for converting said added output into an analog signal and providing said analog signal as said reference voltage.
Claim 10
Dependent Claim
88 words
A: output level control circuit as claimed in any one of claims 1 to 6, wherein said reference voltage control means comprises memory means for storing the bias voltage set in advance and said input reference voltage; controller means for generating an added output by adding said stored bias voltage and said stored input reference voltage synchronized with the on-state of said transmitting signal; and digital to analog conversion means for converting said added output to an analog signal and producing said analog signal as said reference voltage.
Claim 11
Dependent Claim
156 words
An output level control circuit for radio-frequency transmitter, comprising: variable gain amplifier means for amplifying an intermittently supplied radio-frequency transmitting signal in response to a control signal to produce an amplified signal; signal detection means including a signal coupler which branches off a part of said amplified, a detecting diode which outputs to a load resistor the added output voltage of the output of detection means and an input bias voltage, and bias means which keeps the bias voltage of said detecting diode at substantially constant level irrespective of the temperature variations; comparator means for comparing a reference voltage and said added output voltage; power control means for generating said control signal in response to the output of said comparator means; and reference voltage control means for generating said reference voltage by adding the bias voltage of said detecting diode to an input reference voltage that is supplied synchronized with the on-state of said transmitting signal.
Claim 12
Dependent Claim
57 words
An output level control circuit as claimed in claim 11, wherein said reference voltage control means includes bias voltage detection means for storing the bias voltage of the detecting diode during the off-state of said transmitting signal, and reference voltage addition means for generating said reference voltage by adding said bias voltage to said input reference voltage.
Claim 13
Dependent Claim
107 words
An output level control circuit as claimed in claim 11, wherein said reference voltage control means includes analog to digital conversion means for converting said added output voltage to a first digital signal, memory means for storing a second digital signal that corresponds to the bias voltage of said detecting diode constituting a part of said first digital signal, controller means connected to said analog to digital conversion means and said memory means for generating the added output by adding said stored bias voltage to said input reference voltage of digital mode, and digital to analog conversion means for converting said added output to said reference voltage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.