JP3082922B2 - Radio receiver - Google Patents
Radio receiverInfo
- Publication number
- JP3082922B2 JP3082922B2 JP01296933A JP29693389A JP3082922B2 JP 3082922 B2 JP3082922 B2 JP 3082922B2 JP 01296933 A JP01296933 A JP 01296933A JP 29693389 A JP29693389 A JP 29693389A JP 3082922 B2 JP3082922 B2 JP 3082922B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- signal
- agc
- wideband
- radio receiver
- 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.)
- Expired - Fee Related
Links
Landscapes
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
Description
【発明の詳細な説明】 （イ）産業上の利用分野 本発明は、自動選局動作時の誤停止を防止し得るラジ
オ受信機に関する。The present invention relates to a radio receiver capable of preventing an erroneous stop during an automatic channel selection operation.
（ロ）従来の技術 混合回路の出力端に得られる広帯域IF（中間周波）信
号を用いて、RF（ラジオ周波）増幅回路の利得制御を行
なう広帯域AGC回路を備えるラジオ受信機が知られてい
る。前記広帯域AGC回路は、前記広帯域IF信号のレベル
が大になると、RF増幅回路の利得を下げ、混合回路に印
加されるRF信号のレベルを低下させているので、混合回
路の飽和を防止することが出来、相互変調妨害特性を改
善することが出来る。(B) Conventional technology A radio receiver having a wideband AGC circuit for controlling a gain of an RF (radio frequency) amplifier circuit using a wideband IF (intermediate frequency) signal obtained at an output terminal of a mixing circuit is known. . The wideband AGC circuit reduces the gain of the RF amplifier circuit when the level of the wideband IF signal increases, and lowers the level of the RF signal applied to the mixing circuit, thereby preventing saturation of the mixing circuit. And the intermodulation interference characteristic can be improved.
（ハ）発明が解決しようとする課題 しかしながら、前記広帯域AGC回路をかけると、希望
信号が弱く妨害信号が強い場合に利得制御が行なわれ、
希望信号に対する感度抑圧が生じるという問題があっ
た。(C) Problems to be Solved by the Invention However, when the wideband AGC circuit is applied, gain control is performed when a desired signal is weak and an interference signal is strong,
There is a problem that sensitivity suppression for a desired signal occurs.
前記感度抑圧を防止する為には、受信信号（希望信
号）の電界強度を検出し、それに応じて広帯域AGC信号
の制御を行なえばよい。例えば、希望信号のレベルが小
の場合は、広帯域AGC信号を抑さえ、AGCのきき具合を悪
化させれば、希望信号の感度抑圧を防止し得る。しかし
ながら、その場合、希望信号が無い場合、AGCがかから
ない状態となり、特に自動選局時においては、妨害信号
チャンネルにて誤停止するという問題があった。In order to prevent the sensitivity suppression, the electric field strength of the received signal (desired signal) may be detected, and the wideband AGC signal may be controlled accordingly. For example, when the level of the desired signal is small, the suppression of the sensitivity of the desired signal can be prevented by suppressing the wideband AGC signal and deteriorating the AGC performance. However, in this case, if there is no desired signal, AGC is not applied, and there is a problem that the automatic stop causes an erroneous stop on the interference signal channel.
（ニ）課題を解決するための手段 本発明は、上述の点に鑑み成されたもので、広帯域AG
C回路と、受信信号の電界強度に応じて前記広帯域AGC回
路を制御する制御回路と、自動選局時に前記制御回路の
動作を強制的に停止させる停止手段とを備える点を特徴
とする。(D) Means for Solving the Problems The present invention has been made in view of the above points, and has been made in consideration of the above-described problems.
It is characterized by comprising a C circuit, a control circuit for controlling the wideband AGC circuit according to the electric field strength of the received signal, and a stopping means for forcibly stopping the operation of the control circuit during automatic channel selection.
（ホ）作 用 本発明に依れば、自動選局時においては、停止手段が
動作し、広帯域AGC回路のみが動作する為、正常な広帯
域AGC動作が行なわれ、自動選局が妨害信号チャンネル
で誤停止するのを防止し得る。また、受信時において
は、広帯域AGC回路及び制御回路が動作するので、相互
変調妨害特性及び希望信号の感度抑圧を同時に改善する
ことが出来る。(E) Operation According to the present invention, at the time of automatic channel selection, the stop means operates and only the wideband AGC circuit operates, so that normal wideband AGC operation is performed, and automatic channel selection is performed by the interference signal channel. To prevent an erroneous stop. Also, at the time of reception, since the wideband AGC circuit and the control circuit operate, it is possible to simultaneously improve the intermodulation interference characteristics and the suppression of the sensitivity of the desired signal.
（ヘ）実施例 第１図は、本発明の一実施例を示す回路図で、（１）
はアンテナ、（２）は該アンテナ（１）に受信されたRF
信号を増幅するRF増幅回路、（３）は該RF増幅回路
（２）の出力信号と局部発振回路（４）の出力信号とを
混合してIF信号を作成する混合回路、（５）は前記IF信
号を増幅するIF増幅回路、（６）は該IF増幅回路（５）
の出力信号を検波する検波回路、（７）は前記混合回路
（３）から得られる広帯域IF信号に応じたAGC信号を発
生し、RF増幅回路（２）の利得制御を行なう広帯域AGC
回路、（８）は前記IF増幅回路（５）から得られる受信
信号の電界強度を示す信号に応じて、前記広帯域AGC回
路（７）を制御する制御回路、及び（９）は自動選局時
に前記制御回路（８）の動作を停止させる停止信号が印
加される入力端子である。尚、広帯域AGC回路（７）の
入力としては、混合回路（３）に印加されるRF信号を用
いてもよい。(F) Embodiment FIG. 1 is a circuit diagram showing one embodiment of the present invention.
Is the antenna, (2) is the RF received by the antenna (1)
An RF amplifier circuit for amplifying a signal; (3) a mixing circuit for mixing an output signal of the RF amplifier circuit (2) and an output signal of a local oscillation circuit (4) to generate an IF signal; IF amplifier circuit for amplifying the IF signal, (6) is the IF amplifier circuit (5)
(7) generates an AGC signal corresponding to the wideband IF signal obtained from the mixing circuit (3) and controls the gain of the RF amplifier circuit (2).
A circuit, (8) a control circuit for controlling the wideband AGC circuit (7) in accordance with a signal indicating the electric field strength of the received signal obtained from the IF amplifier circuit (5), and (9) a circuit for automatic channel selection. An input terminal to which a stop signal for stopping the operation of the control circuit (8) is applied. Note that an RF signal applied to the mixing circuit (3) may be used as an input of the wideband AGC circuit (7).
いま、ラジオ受信機が自動選局状態にあるとすれば、
入力端子（９）に停止信号が印加され、制御回路（８）
の動作が強制停止させられる。その為、広帯域AGC回路
（７）は混合回路（３）から得られる広帯域IF信号のみ
に基づき動作し、強大な妨害信号が存在する場合にも前
記広帯域AGC回路（７）が動作して混合回路（３）が飽
和するのを防止し得る。また、AGC動作により、妨害信
号のレベルが十分に抑圧されるので、自動選局が妨害信
号チャンネルで停止するのを防止出来、誤停止の防止が
達成される。Now, if the radio receiver is in the automatic tuning state,
The stop signal is applied to the input terminal (9), and the control circuit (8)
Operation is forcibly stopped. Therefore, the wideband AGC circuit (7) operates based only on the wideband IF signal obtained from the mixing circuit (3), and the wideband AGC circuit (7) operates even when a strong interfering signal is present. (3) can be prevented from being saturated. Further, since the level of the interference signal is sufficiently suppressed by the AGC operation, it is possible to prevent the automatic tuning from being stopped in the interference signal channel, and to prevent the erroneous stop.
自動選局が受信信号（希望信号）に応じて停止する
と、ラジオ受信機は受信状態となるが、それに応じて入
力端子（９）に停止信号が印加されなくなり、制御回路
（８）が動作を開始する。前記制御回路（８）は、IF増
幅回路（５）から得られる受信信号の電界強度を示す信
号に応じて、広帯域AGC回路（７）を制御する。前記電
界強度を示す信号が大レベルであれば、制御回路（８）
は、RF増幅回路（２）の利得が十分に低下する様、広帯
域AGC回路（７）を制御する。また、前記電界強度を示
す信号が小レベルであれば、制御回路（８）は、RF増幅
回路（２）の利得を低下させない様、広帯域AGC回路
（７）を制御する。従って、受信時においては、制御回
路（８）の作用により、二信号特性が改善され、良好な
受信特性が得られる。When the automatic tuning stops in response to the received signal (desired signal), the radio receiver enters a receiving state, but the stop signal is not applied to the input terminal (9) in response thereto, and the control circuit (8) operates. Start. The control circuit (8) controls the wideband AGC circuit (7) according to a signal indicating the electric field strength of the received signal obtained from the IF amplifier circuit (5). If the signal indicating the electric field strength is a large level, the control circuit (8)
Controls the wideband AGC circuit (7) so that the gain of the RF amplifier circuit (2) is sufficiently reduced. If the signal indicating the electric field strength is at a low level, the control circuit (8) controls the wideband AGC circuit (7) so as not to lower the gain of the RF amplifier circuit (2). Therefore, at the time of reception, the two-signal characteristics are improved by the operation of the control circuit (8), and good reception characteristics are obtained.
第２図は、本発明の具体回路例を示すもので、入力端
子（10）に印加された広帯域IF信号は、レベル検波回路
（11）で検波され、第１トランジスタ（12）で増幅さ
れ、そのコレクタからAGC信号としてRF増幅回路（２）
を構成するFET（13）の第２ゲートに印加される。前記
レベル検波回路（11）の出力信号レベルが大であれば、
前記第１トランジスタ（12）のコレクタ電圧が低下し、
FET（13）の第２ゲートの電圧が低下するので、RF増幅
回路の利得が低下する。また、前記レベル検波回路（1
1）の出力信号レベルが小であれば、第１トランジスタ
（12）のコレクタ電圧が上昇し、FET（13）の第２ゲー
トの電圧が上昇するので、RF増幅回路の利得が上昇す
る。FIG. 2 shows a specific circuit example of the present invention. A wide-band IF signal applied to an input terminal (10) is detected by a level detection circuit (11) and amplified by a first transistor (12). RF amplification circuit (2) from the collector as AGC signal
Is applied to the second gate of the FET (13). If the output signal level of the level detection circuit (11) is high,
The collector voltage of the first transistor (12) decreases,
Since the voltage of the second gate of the FET (13) decreases, the gain of the RF amplifier circuit decreases. In addition, the level detection circuit (1
If the output signal level of 1) is low, the collector voltage of the first transistor (12) increases and the voltage of the second gate of the FET (13) increases, so that the gain of the RF amplifier circuit increases.
一方、入力端子（14）には、IF増幅回路からの受信信
号の電界強度を示す信号が印加される。前記信号が大の
場合、第２及び第３トランジスタ（15）及び（16）がオ
フになり、第４トランジスタ（17）のベースが抵抗（1
8）及び（19）とダイオード（20）とによってバイアス
され、前記第４トランジスタ（17）がオンとなる。従っ
て、第１トランジスタ（12）は、前記第４トランジスタ
（17）のコレクタ電流により制限を受けず、レベル検波
回路（11）の出力信号に応じた広帯域AGC動作を行な
う。入力端子（14）に印加される信号が小になると、そ
れに応じて第２及び第３トランジスタ（15）及び（16）
が導通を開始し、第４トランジスタ（17）のベースバイ
アス電流が減少する。その為、レベル検波回路（11）の
出力信号レベルが大になったとき、第１トランジスタ
（12）は前記出力信号レベルに応じたコレクタ電流を流
すことが出来なくなり、前記第１トランジスタ（12）の
コレクタ電圧が十分に低下せず、広帯域AGC回路のAGC減
衰量が制約される。入力端子（14）に印加される信号が
極く小になると、抵抗（18）を流れる電流はすべて第３
トランジスタ（16）に流れ、第４トランジスタ（17）が
オフになる。その為、第１トランジスタ（12）のエミッ
タ電流路が形成されなくなり、広帯域AGC信号が発生し
なくなる。従って、RF増幅回路は、最大利得で動作し、
受信信号は十分に増幅される。On the other hand, a signal indicating the electric field strength of the received signal from the IF amplifier circuit is applied to the input terminal (14). When the signal is large, the second and third transistors (15) and (16) are turned off, and the base of the fourth transistor (17) is connected to the resistor (1).
Biased by 8) and (19) and diode (20), the fourth transistor (17) is turned on. Accordingly, the first transistor (12) is not limited by the collector current of the fourth transistor (17) and performs a wideband AGC operation according to the output signal of the level detection circuit (11). When the signal applied to the input terminal (14) becomes small, the second and third transistors (15) and (16)
Starts conducting, and the base bias current of the fourth transistor (17) decreases. Therefore, when the output signal level of the level detection circuit (11) increases, the first transistor (12) cannot flow a collector current corresponding to the output signal level, and the first transistor (12) , The AGC attenuation of the broadband AGC circuit is restricted. When the signal applied to the input terminal (14) becomes extremely small, all the current flowing through the resistor (18) becomes the third current.
The current flows to the transistor (16), and the fourth transistor (17) is turned off. Therefore, the emitter current path of the first transistor (12) is not formed, and the wide band AGC signal is not generated. Therefore, the RF amplifier operates at the maximum gain,
The received signal is sufficiently amplified.
自動選局時には、入力端子（21）に停止信号が印加さ
れ、受信時には前記入力端子（21）に停止信号が印加さ
れない。前記入力端子（21）に停止信号が印加される
と、第５トランジスタ（22）がオンし、第６及び第７ト
ランジスタ（23）及び（24）もオンする。その為、抵抗
（25）に電流が流れ、第２トランジスタ（15）のベース
電圧が上昇し、該第２トランジスタ（15）が強制オフと
なる。また、前記入力端子（21）に停止信号が印加され
ない場合は、第５乃至第７トランジスタ（22）乃至（2
4）がオフになり、制御回路は入力端子（14）に印加さ
れる信号に応じた動作を行なう。At the time of automatic channel selection, a stop signal is applied to the input terminal (21), and at the time of reception, no stop signal is applied to the input terminal (21). When a stop signal is applied to the input terminal (21), the fifth transistor (22) turns on, and the sixth and seventh transistors (23) and (24) also turn on. Therefore, a current flows through the resistor (25), the base voltage of the second transistor (15) increases, and the second transistor (15) is forcibly turned off. When the stop signal is not applied to the input terminal (21), the fifth to seventh transistors (22) to (2)
4) is turned off, and the control circuit performs an operation according to the signal applied to the input terminal (14).
（ト）発明の効果 以上述べた如く、本発明に依れば、広帯域AGC回路を
備えているので、相互変調妨害特性を改善することが出
来る。また、制御回路を備え、受信信号の電界強度に応
じて広帯域AGC回路を制御しているので、妨害信号に起
因する受信信号（希望信号）の感度抑圧を防止出来る。
更に、自動選局時に前記制御回路の動作を停止させてい
るので、自動選局の誤停止を防止し得る。(G) Effects of the Invention As described above, according to the present invention, since the wideband AGC circuit is provided, the intermodulation interference characteristic can be improved. Further, since the control circuit is provided to control the wideband AGC circuit according to the electric field strength of the received signal, it is possible to prevent the sensitivity of the received signal (desired signal) from being suppressed due to the interference signal.
Further, since the operation of the control circuit is stopped at the time of automatic channel selection, erroneous stop of automatic channel selection can be prevented.
第１図は、本発明の一実施例を示す回路図及び第２図は
その具体回路例を示す回路図である。 （７）……広帯域AGC回路、（８）……制御回路、
（９）……入力端子。FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a specific circuit example. (7) ... broadband AGC circuit, (8) ... control circuit,
(9) ... input terminal.
Claims (3)
じて前記広帯域AGC回路のきき具合を制御する制御回路
とを備えるラジオ受信機において、自動選局時に前記制
御回路の動作を強制的に停止させ、前記広帯域AGC回路
のみを動作させることを特徴とするラジオ受信機。1. A radio receiver comprising a wide-band AGC circuit and a control circuit for controlling the degree of the wide-band AGC circuit according to the electric field strength of an IF signal, the operation of the control circuit is forcibly performed during automatic channel selection. A radio receiver, wherein only the wideband AGC circuit is operated.
に得られる広帯域IF信号又は前記混合回路に印加される
RF信号のレベルを検出し、RF増幅回路の利得を制御する
様に構成されている請求項１記載のラジオ受信機。2. The wideband AGC circuit is applied to a wideband IF signal obtained at an output terminal of the mixing circuit or to the mixing circuit.
2. The radio receiver according to claim 1, wherein the level of the RF signal is detected and the gain of the RF amplifier circuit is controlled.
出する検出回路を備え、該検出回路の出力信号が低下し
たとき、前記広帯域AGC回路からAGC信号が発生するのを
阻止する方向の制御を行うことを特徴とする請求項１記
載のラジオ受信機。3. The control circuit according to claim 1, further comprising a detection circuit for detecting an electric field intensity of the received signal, wherein the output signal of the detection circuit decreases to prevent an AGC signal from being generated from the wideband AGC circuit. The radio receiver according to claim 1, wherein the radio receiver performs control.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01296933A JP3082922B2 (en) | 1989-11-15 | 1989-11-15 | Radio receiver |
| US07/612,551 US5321851A (en) | 1989-11-15 | 1990-11-13 | Radio receiver comprising automatic gain controlling function |
| KR1019900018422A KR960000524B1 (en) | 1989-11-15 | 1990-11-14 | Radio receiver |
| DE69025546T DE69025546T2 (en) | 1989-11-15 | 1990-11-15 | Radio receiver with automatic gain control |
| EP90121896A EP0428170B1 (en) | 1989-11-15 | 1990-11-15 | Radio receiver comprising automatic gain controlling function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01296933A JP3082922B2 (en) | 1989-11-15 | 1989-11-15 | Radio receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03158021A JPH03158021A (en) | 1991-07-08 |
| JP3082922B2 true JP3082922B2 (en) | 2000-09-04 |
Family
ID=17840052
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP01296933A Expired - Fee Related JP3082922B2 (en) | 1989-11-15 | 1989-11-15 | Radio receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3082922B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5481226A (en) * | 1994-10-25 | 1996-01-02 | Motorola, Inc. | Low-voltage intermediate frequency amplifier providing automatic gain control of a source amplifier |
-
1989
- 1989-11-15 JP JP01296933A patent/JP3082922B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03158021A (en) | 1991-07-08 |
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