JPH0897734A - Automatic transmission power control circuit for AM / FM transmitter - Google Patents
Automatic transmission power control circuit for AM / FM transmitterInfo
- Publication number
- JPH0897734A JPH0897734A JP25901294A JP25901294A JPH0897734A JP H0897734 A JPH0897734 A JP H0897734A JP 25901294 A JP25901294 A JP 25901294A JP 25901294 A JP25901294 A JP 25901294A JP H0897734 A JPH0897734 A JP H0897734A
- Authority
- JP
- Japan
- Prior art keywords
- control circuit
- transmission
- modulated wave
- output
- power amplifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Transmitters (AREA)
Abstract
(57)【要約】
【目的】ＡＭ送信機でディジタルデータなどのＦＭ変調
波の送信を共用する場合、自動送信電力制御回路の制御
動作が遅いために生ずる立上り時のデータ欠落をなく
す。
【構成】電力増幅器１から出力される送信電力の一部を
抽出して検波器２で検波した出力から直流信号を取り出
すＬＰＦ３の出力側の対接地間に切換器５と抵抗Ｒの直
列回路を設ける。ＡＭ変調波送信のときは切換器５をオ
フ状態とし、送信出力レベルに対応する直流信号をその
まま制御回路４に与えて電力増幅器１の利得を制御す
る。ＦＭ変調波送信のときは切換器５をオンにしてＬＰ
Ｆ３の出力インピーダンスより小さい値の抵抗Ｒを入
れ、制御回路４から一定の制御信号を出力させるように
構成した。
(57) [Abstract] [Purpose] When the AM transmitter shares the transmission of FM modulated waves such as digital data, the loss of data at the rising edge caused by the slow control operation of the automatic transmission power control circuit is eliminated. A series circuit of a switcher 5 and a resistor R is provided between the output side of an LPF 3 for grounding, which extracts a direct current signal from an output detected by a detector 2 by extracting a part of transmission power output from a power amplifier 1. Set up. At the time of AM modulated wave transmission, the switch 5 is turned off, and a DC signal corresponding to the transmission output level is directly applied to the control circuit 4 to control the gain of the power amplifier 1. When transmitting FM modulated wave, switch 5 is turned on and LP
A resistor R having a value smaller than the output impedance of F3 is inserted so that the control circuit 4 outputs a constant control signal.
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ＡＭ変調波，ＦＭ変調
波の送信を共用する送信機の自動送信電力制御（ＡＰ
Ｃ）回路に関し、特に、ＡＭ送信機でＦＭ送信を共用す
る場合の改良に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to automatic transmission power control (AP) of a transmitter that shares the transmission of AM modulated waves and FM modulated waves.
The present invention relates to a circuit, and particularly to an improvement in the case where an AM transmitter shares FM transmission.
【０００２】[0002]
【従来の技術】図２はＡＭ変調波を送信する送信機のＡ
ＰＣ回路部分のブロック図である。図において、１は送
信信号を増幅する電力増幅器、２は電力増幅器１の出力
送信電力の一部を抽出して検波する検波器、３は検波出
力から直流成分（ＤＣ信号）を取り出す低域ろ波器（Ｌ
ＰＦ）である。４は制御回路であり、送信出力レベルに
対応して変化するＤＣ信号を基準値と比較し、電力増幅
器１の利得を制御し送信出力を一定に保つ。ＬＰＦ３
は、ＡＭ変調する変調信号の変化には追従せず、送信出
力の緩やかな変動に追従するようなカットオフ周波数に
設定されており、自動電力制御（ＡＰＣ）動作の立ち上
り時間は、このＬＰＦ３の時定数により決定されてお
り、ＡＭ変調波を送信する場合はこの時定数により遅延
時間が発生するが実用上は問題はない。2. Description of the Related Art FIG. 2 shows a transmitter A for transmitting an AM modulated wave.
It is a block diagram of a PC circuit portion. In the figure, 1 is a power amplifier that amplifies a transmission signal, 2 is a detector that extracts and detects a part of the output transmission power of the power amplifier 1, and 3 is a low-pass filter that extracts a DC component (DC signal) from the detection output. Wave instrument (L
PF). Reference numeral 4 denotes a control circuit, which compares a DC signal that changes according to the transmission output level with a reference value, controls the gain of the power amplifier 1, and keeps the transmission output constant. LPF3
Is set to a cutoff frequency that does not follow the change in the modulation signal to be AM-modulated, but follows a gradual change in the transmission output, and the rise time of the automatic power control (APC) operation is It is determined by the time constant, and when transmitting an AM modulated wave, a delay time occurs due to this time constant, but there is no problem in practical use.
【０００３】[0003]
【発明が解決しようとする課題】しかし、このようなＡ
Ｍ送信機でＦＭ変調波を送信する場合は、立ち上りの速
いＡＰＣ特性が要求されるため、前述の遅延時間のため
立ち上り時間が遅いことが欠点となる。すなわち、変調
信号が音声信号の場合は問題ないが、特に、データ伝送
など送信の立ち上り部分に同期信号などの重要な情報が
ある場合は伝送情報が欠落するという欠点が生ずる。However, such A
When the FM transmitter is transmitted by the M transmitter, an APC characteristic with a fast rise is required, and thus the rise time is delayed due to the delay time described above, which is a drawback. That is, there is no problem when the modulated signal is a voice signal, but there is a drawback that the transmission information is lost particularly when important information such as a synchronization signal is present at the rising edge of transmission such as data transmission.
【０００４】本発明の目的は、ＡＭ変調波の送信機でデ
ィジタルデータなどのＦＭ変調波の送信を共用する場合
でも、従来技術の問題点となるＬＰＦの遅延時間による
ＡＰＣ動作の立ち上り時間の遅延を回避した自動送信電
力制御回路を提供することにある。An object of the present invention is to delay the rise time of the APC operation due to the delay time of the LPF, which is a problem of the prior art, even when the transmitter of the AM modulated wave shares the transmission of the FM modulated wave such as digital data. It is to provide an automatic transmission power control circuit that avoids the above.
【０００５】[0005]
【課題を解決するための手段】本発明のＡＭ・ＦＭ用送
信機のＡＰＣ回路は、ＡＭ変調波，ＦＭ変調波を電力増
幅する電力増幅器の出力送信電力の一部を抽出して検波
した後、低域ろ波器を通して得られた直流信号を制御回
路に入力して前記電力増幅器の送信出力が一定になるよ
うに該電力増幅器の利得を制御する自動送信電力制御回
路において、前記低域ろ波器の出力端と接地との間に、
該低域ろ波器の時定数を変えるための切換器と抵抗との
直列回路を設け、ＡＭ変調波を送信するとき該切換器を
オフにして前記直流信号をそのまま前記制御回路に入力
し、ＦＭ変調波を送信するとき該切換器をオンにして前
記低域ろ波器の時定数を変えて制御動作の立ち上り時間
を短くするように構成したことを特徴とするものであ
る。The APC circuit of the AM / FM transmitter of the present invention extracts and detects a part of the output transmission power of the power amplifier for power amplification of the AM modulation wave and the FM modulation wave. In the automatic transmission power control circuit for controlling the gain of the power amplifier so that the transmission output of the power amplifier becomes constant by inputting the DC signal obtained through the low-pass filter to the control circuit. Between the output end of the wave device and the ground,
A series circuit of a switch and a resistor for changing the time constant of the low-pass filter is provided, and when the AM modulated wave is transmitted, the switch is turned off and the DC signal is directly input to the control circuit. When the FM modulated wave is transmitted, the switch is turned on to change the time constant of the low-pass filter to shorten the rising time of the control operation.
【０００６】[0006]
【実施例】図１は本発明の実施例を示す回路ブロック図
であり、ＡＭ変調波，ＦＭ変調波の両方を送信できる送
信機のＡＰＣ回路である。図において、１は送信信号を
増幅する電力増幅器、２は電力増幅器１の出力送信電力
の一部を抽出して検波する検波回路、３は検波出力から
直流信号（ＤＣ信号）を取り出すＬＰＦ、４はＤＣ信号
により電力増幅器１の利得を制御する制御回路、５はＡ
Ｍ・ＦＭ変調波のいずれかに応じてＡＰＣ動作の時定数
を切換えるための切換器、Ｒは直列抵抗である。この回
路により、ＡＭ変調波を送信する場合は切換器５をオフ
にしてＬＰＦ３によりＡＭ変調波の送信電力レベルの変
動分を検出して電力増幅器１にフィードバックすること
によりＡＰＣ動作が行われる。一方、ＦＭ変調波を送信
する場合は、送信信号の振幅特性はＦＭ変調波の復調に
は関係ないため、切換器５をオンにして抵抗Ｒを接地間
に挿入し制御回路４の入力電圧を一定にすることによ
り、ＬＰＦ３の時定数に関係なく立ち上りの速いＡＰＣ
動作が行われる。抵抗Ｒの値はＬＰＦ３の出力インピー
ダンスの１／５以下に設定される。本発明により、ＡＭ
・ＦＭ変調波の両方の送信信号に対応できる送信機を実
現することができる。1 is a circuit block diagram showing an embodiment of the present invention, which is an APC circuit of a transmitter capable of transmitting both an AM modulated wave and an FM modulated wave. In the figure, 1 is a power amplifier that amplifies a transmission signal, 2 is a detection circuit that extracts and detects a part of the output transmission power of the power amplifier 1, 3 is an LPF that extracts a DC signal (DC signal) from the detection output, 4 Is a control circuit for controlling the gain of the power amplifier 1 by a DC signal, and 5 is A
A switch for switching the time constant of the APC operation according to either of the M and FM modulated waves, and R is a series resistor. With this circuit, when transmitting an AM modulated wave, the switch 5 is turned off, the LPF 3 detects a variation in the transmission power level of the AM modulated wave, and feeds it back to the power amplifier 1 to perform the APC operation. On the other hand, when the FM modulated wave is transmitted, the amplitude characteristic of the transmission signal is not related to the demodulation of the FM modulated wave, so that the switch 5 is turned on and the resistor R is inserted between the ground and the input voltage of the control circuit 4 is changed. By keeping it constant, APC with a fast start-up regardless of the time constant of LPF3
The action is taken. The value of the resistor R is set to 1/5 or less of the output impedance of the LPF 3. According to the present invention, AM
It is possible to realize a transmitter that can handle both transmission signals of FM modulated waves.
【０００７】[0007]
【発明の効果】本発明を実施することにより、ＡＭ変調
波とＦＭ変調波の送信を共用し、ＦＭ変調波の送信時に
速いアタックタイムが要求される場合に、立ち上り部分
のデータ伝送情報が欠落することなく送信することがで
きる。By implementing the present invention, when the transmission of the AM modulated wave and the FM modulated wave is shared and a fast attack time is required at the time of transmitting the FM modulated wave, the data transmission information at the rising portion is lost. Can be sent without doing.
【図１】本発明の実施例を示すブロック図である。FIG. 1 is a block diagram showing an embodiment of the present invention.
【図２】従来のＡＭ変調波の送信機におけるＡＰＣ回路
例図である。FIG. 2 is a diagram showing an example of an APC circuit in a conventional AM modulated wave transmitter.
１ 電力増幅器 ２ 検波器 ３ ＬＰＦ ４ 制御回路 ５ 切換器 1 Power Amplifier 2 Detector 3 LPF 4 Control Circuit 5 Switch
Claims (1)
電力増幅器の出力送信電力の一部を抽出して検波した
後、低域ろ波器を通して得られた直流信号を制御回路に
入力して前記電力増幅器の送信出力が一定になるように
該電力増幅器の利得を制御する自動送信電力制御回路に
おいて、 前記低域ろ波器の出力端と接地との間に、該低域ろ波器
の時定数を変えるための切換器と抵抗との直列回路を設
け、ＡＭ変調波を送信するとき該切換器をオフにして前
記直流信号をそのまま前記制御回路に入力し、ＦＭ変調
波を送信するとき該切換器をオンにして前記低域ろ波器
の時定数を変えて制御動作の立ち上り時間を短くするよ
うに構成したことを特徴とするＡＭ・ＦＭ用送信機の自
動送信電力制御回路。1. A part of output transmission power of a power amplifier for amplifying AM modulated wave and FM modulated wave is extracted and detected, and a DC signal obtained through a low-pass filter is input to a control circuit. In the automatic transmission power control circuit for controlling the gain of the power amplifier so that the transmission output of the power amplifier becomes constant, the low-pass filter is provided between the output terminal of the low-pass filter and the ground. A series circuit of a switch and a resistor for changing the time constant of is provided, and when the AM modulated wave is transmitted, the switch is turned off and the DC signal is directly input to the control circuit to transmit the FM modulated wave. At this time, the automatic transmission power control circuit of the AM / FM transmitter is characterized in that the switching device is turned on to change the time constant of the low-pass filter to shorten the rise time of the control operation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25901294A JPH0897734A (en) | 1994-09-29 | 1994-09-29 | Automatic transmission power control circuit for AM / FM transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25901294A JPH0897734A (en) | 1994-09-29 | 1994-09-29 | Automatic transmission power control circuit for AM / FM transmitter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0897734A true JPH0897734A (en) | 1996-04-12 |
Family
ID=17328129
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25901294A Pending JPH0897734A (en) | 1994-09-29 | 1994-09-29 | Automatic transmission power control circuit for AM / FM transmitter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0897734A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006238064A (en) * | 2005-02-25 | 2006-09-07 | Nec Corp | Transmission output controller, its method, and transmitter using the same |
-
1994
- 1994-09-29 JP JP25901294A patent/JPH0897734A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006238064A (en) * | 2005-02-25 | 2006-09-07 | Nec Corp | Transmission output controller, its method, and transmitter using the same |
| US7519133B2 (en) | 2005-02-25 | 2009-04-14 | Nec Corporation | Transmission output control apparatus and its method, transmitter using the same, and recording medium recording transmission output control program |
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