JPS5941605B2 - electronic tuning receiver - Google Patents
electronic tuning receiverInfo
- Publication number
- JPS5941605B2 JPS5941605B2 JP6916279A JP6916279A JPS5941605B2 JP S5941605 B2 JPS5941605 B2 JP S5941605B2 JP 6916279 A JP6916279 A JP 6916279A JP 6916279 A JP6916279 A JP 6916279A JP S5941605 B2 JPS5941605 B2 JP S5941605B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- time constant
- signal
- tuning
- frequency
- 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
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J7/00—Automatic frequency control; Automatic scanning over a band of frequencies
- H03J7/18—Automatic scanning over a band of frequencies
Landscapes
- Circuits Of Receivers In General (AREA)
- Control Of Amplification And Gain Control (AREA)
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
Description
【発明の詳細な説明】
この発明は自動選局動作を速くしても誤選局を起こすこ
とがない電子同調式受信装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronically tuned receiver that does not cause erroneous channel selection even when the automatic channel selection operation is accelerated.
第１図は従来の電子同調式受信機を示すブロック図であ
る。FIG. 1 is a block diagram showing a conventional electronically tuned receiver.
同図において、１はアンテナ、２は可変同調回路および
可変利得回路を含む高周波増幅回路、３は高周波を中間
周波数に変換するための局部発振周波数との混合回路、
４は同調回路を含む中間周波増幅回路、５は検波回路を
含む音声周波増幅回路、６はスピーカ、Ｔは発振周波数
の可変可能な局部発振器、８はこの局部発振器□の発振
周波数またはその発振周波数の位相を制御すると共に高
周波増幅回路２の同調周波数を制御する同調周波数制御
回路、９は急峻な選択特性の同調回路をもつ信号検知回
路、１０はこの信号検知回路９から入力する検知信号に
より、選局動作を止めるまたは継続するなどの信号を送
り出す総合制御回路、１１はその詳細な回路を第３図に
示すように、検波回路を含む利得制御時定数（ＡＧＣル
ープフィルタ）回路である。なお、第２図は第１図のＡ
点からＢ点までの各周波数または各チャンネルに同調さ
せたときの周波数−利得曲線を示す図である。In the figure, 1 is an antenna, 2 is a high frequency amplification circuit including a variable tuning circuit and a variable gain circuit, 3 is a mixing circuit with a local oscillation frequency for converting the high frequency into an intermediate frequency,
4 is an intermediate frequency amplification circuit including a tuning circuit, 5 is an audio frequency amplification circuit including a detection circuit, 6 is a speaker, T is a local oscillator whose oscillation frequency is variable, and 8 is an oscillation frequency of this local oscillator □ or its oscillation frequency. 9 is a signal detection circuit having a tuning circuit with steep selection characteristics, and 10 is a detection signal inputted from this signal detection circuit 9. The general control circuit 11 sends out a signal to stop or continue the channel selection operation, the detailed circuit of which is shown in FIG. 3, is a gain control time constant (AGC loop filter) circuit including a detection circuit. Note that Figure 2 is A of Figure 1.
It is a figure which shows the frequency-gain curve when it tunes to each frequency or each channel from point B.
また、第３図に示す利得制御時定数（ＡＧＣループフィ
ルタ）回路１１において、Ｉｌａは入力端子、Ｉｌｂは
ダイオード、１１ｃは抵抗、Ｉｌｄはコンデンサ、Ｉｌ
ｅは出力端子である。次に、上記構成に係る電子同調式
受信機の動作について説明する。In addition, in the gain control time constant (AGC loop filter) circuit 11 shown in FIG. 3, Ila is an input terminal, Ilb is a diode, 11c is a resistor, Ild is a capacitor, Il
e is an output terminal. Next, the operation of the electronically tuned receiver having the above configuration will be explained.
まず、アンテナ１に受信された信号波は受信機の同調周
波数と一致しているとき、この信号波は高周波増幅回路
２で増幅されたのち、混合回路３において、局部発振器
７から入力する局部発振周波数と混合され、中間周波と
なる。そして、中間周波増幅回路４に人力した中間周波
の一部は信号検知回路９に入力し、出力検知動作を行な
い、総合制御回路１０および同調周波数制御回路８を介
して高周波増幅回路２の同調周波数および局部発振器７
の発振周波数を固定する。−方、前記中間周波増幅回路
４を通過した信号の一部は利得制御時定数回路１１に入
力し、その出力信号によつて、高周波増幅回路２の利得
可変回路を制御し、中間周波増幅回路４の信号出力レベ
ルを一定にするよう動作する。また、中間周波増幅回路
４の出力の残りの信号波は音声周波増幅回路５を通つて
スピーカ６に入り、音声として出力される。このように
、電子同調式受信機は放送信号波を自動選局するとき、
局部発振周波数と高周波増幅回路の同調周波数を同時に
順次高くするか、または低くするかしながら、信号検知
回路が動作する点を探し、信号検知回路が動作した周波
数で局部発振周波数および同調周波数を固定し、放送受
信状態となる。しかしながら、従来の電子同調式受信機
ではチャンネルを順次切換えてゆく速度、すなわち自動
選局動作を速くすると、誤選択が起る。First, when the signal wave received by the antenna 1 matches the tuning frequency of the receiver, this signal wave is amplified by the high-frequency amplifier circuit 2, and then the local oscillator input from the local oscillator 7 is sent to the mixing circuit 3. It is mixed with the frequency and becomes an intermediate frequency. A part of the intermediate frequency manually input to the intermediate frequency amplification circuit 4 is input to the signal detection circuit 9, performs an output detection operation, and is transmitted through the general control circuit 10 and the tuning frequency control circuit 8 to the tuning frequency of the high frequency amplifier circuit 2. and local oscillator 7
Fix the oscillation frequency. - On the other hand, a part of the signal that has passed through the intermediate frequency amplifier circuit 4 is input to the gain control time constant circuit 11, and the output signal controls the variable gain circuit of the high frequency amplifier circuit 2, and the intermediate frequency amplifier circuit It operates to keep the signal output level of 4 constant. Further, the remaining signal wave output from the intermediate frequency amplification circuit 4 passes through the audio frequency amplification circuit 5, enters the speaker 6, and is output as audio. In this way, when electronically tuned receivers automatically tune into broadcast signal waves,
While simultaneously raising or lowering the local oscillation frequency and the tuning frequency of the high-frequency amplifier circuit, find the point where the signal detection circuit operates, and fix the local oscillation frequency and tuning frequency at the frequency at which the signal detection circuit operates. Then, it enters the broadcast reception state. However, in conventional electronically tuned receivers, when the speed at which channels are sequentially switched, that is, the automatic channel selection operation is increased, erroneous selection occurs.
例えば、いま、１０チヤンネルから順次１１チヤンネル
、１２チヤンネル、・・・・・・へと同調点を変えて、
自動選局動作を行なつているとき、１５チヤンネルに強
力な信号波があつたと仮定する。そして、高周波増幅回
路２の可変利得回路ＡＧＣが最大利得状態のとき、アン
テナ１からＡ点に入つた１５チヤンネル信号がこの高周
波増幅回路２の同調回路の選択特性および中間周波増幅
回路４の同調回路の選択特性により、中間周波増幅回路
４の出力端子であるＢ点に到達するレベルは第２図に示
すように、１０チヤンネルおよび１１チヤンネルに同調
したときはほぼ零、１２チヤンネルではレベルイ１３チ
ヤンネルではレベル旧、１４チヤンネルではレベルハ、
１５チヤンネルではレベルニである。したがつて、チヤ
ンネルを順次切換えている速度すなわち、自動選局動作
が利得制（財）時定数（ＡＧＣループフイルタ）回路１
１の時定数よりも速い場合について第３図を用いて説明
する。まず、入力端子１１ａに入力した信号入力は検波
用ダイオード１１ｂで検波されたのち、抵抗１１ｃおよ
びコンデンサ１１ｄよりなる時定数回路を通つて出力端
子１１ｅからＡＧＣ（自動利得制哩）電圧として出力す
るので、第１図のＢ点の信号レベルを一定にするように
働く。ところが、一般にこの抵抗１１ｃおよびコンデン
サ１１ｄの値が大きいため、ＡＧＣ電圧が利得制御時定
数（ＡＧＣループフイルタ）回路１１に入力する信号入
力レベルに相当するまで充分上り切るには、抵抗１１ｃ
の抵抗値とコンデンサ１１ｄの容量との積ＣＸＲすなわ
ち、ＡＧＣループフイルタ時定数に比例した時間を要す
る。このＡＧＣループフイルタ時定数が小さいと、信号
波に含まれる音声振幅変調成分のため、ＡＧＣ制（財）
出力電圧が変化し、正常な信号成分の再生ができない、
逆に、このＡＧＣループフイルタ時定数が大きいと、同
調周波数を順次切換えてゆく自動選局動作（サーチスピ
ード）を早くしたときには、第２図に示すレベルイ、口
、ハに相当するＡＧＣ出力電圧が充分立上がり切れない
内に、次のチヤンネルに同調点が移動する。例えば、１
４チヤンネルに同調が移つたとき、ＡＧＣ電圧が充分立
上らないため、高周波増幅回路２の増幅器のＡＧＣ利得
が最大に近い状態のままであつたとすると、１５チヤン
ネル信号入力波が強大なため、その状態で増幅器の一部
が飽和すると、信号波に含まれる音声信号成分と搬送波
成分による三次歪として１４チヤンネルに相当する信号
が内部で発生する。そのとき、信号検知回路が動作し、
同調周波数が１５チヤンネルに移動しないで、１４チヤ
ンネルで固定されてしまう。すなわち、１４チヤンネル
に受信信号が無いにもかかわらず、１４チヤンネル受信
状態となる。このように、時定数が大きいため、自動選
局動作を速くすると、誤選局が起る欠点があつた。For example, if you change the tuning point from channel 10 to channel 11, channel 12, etc.,
Assume that a strong signal wave is received on channel 15 during automatic channel selection. When the variable gain circuit AGC of the high frequency amplifier circuit 2 is in the maximum gain state, the 15 channel signal entering the point A from the antenna 1 changes the selection characteristics of the tuning circuit of the high frequency amplifier circuit 2 and the tuning circuit of the intermediate frequency amplifier circuit 4. Due to the selection characteristics of , the level that reaches point B, which is the output terminal of the intermediate frequency amplification circuit 4, is almost zero when tuned to channels 10 and 11, as shown in Fig. 2, and is at a level of 13 when tuned to channel 12. Level old, Level 14 channel,
Channel 15 is Rebelni. Therefore, the speed at which channels are sequentially switched, that is, the automatic channel selection operation is controlled by the gain-based time constant (AGC loop filter) circuit 1.
The case where the time constant is faster than 1 will be explained using FIG. First, the signal input to the input terminal 11a is detected by the detection diode 11b, and then output as an AGC (automatic gain control) voltage from the output terminal 11e through a time constant circuit consisting of a resistor 11c and a capacitor 11d. , works to keep the signal level at point B in FIG. 1 constant. However, since the values of the resistor 11c and capacitor 11d are generally large, in order for the AGC voltage to rise sufficiently to correspond to the signal input level input to the gain control time constant (AGC loop filter) circuit 11, the resistor 11c is required.
It takes a time proportional to the product CXR of the resistance value of and the capacitance of the capacitor 11d, that is, the AGC loop filter time constant. If this AGC loop filter time constant is small, the AGC control system
The output voltage changes and normal signal components cannot be reproduced.
On the other hand, if the AGC loop filter time constant is large, when the automatic tuning operation (search speed) that sequentially switches the tuning frequency is made faster, the AGC output voltages corresponding to Levels 1, 2, and 2 shown in Figure 2 will increase. The tuning point moves to the next channel before the signal has fully risen. For example, 1
When the tuning shifts to the 4th channel, the AGC voltage does not rise sufficiently, so if the AGC gain of the amplifier in the high frequency amplifier circuit 2 remains close to the maximum, the 15th channel signal input wave is strong, so When a part of the amplifier is saturated in this state, a signal corresponding to 14 channels is generated internally as third-order distortion due to the audio signal component and carrier wave component included in the signal wave. At that time, the signal detection circuit operates,
The tuning frequency does not move to channel 15, but is fixed at channel 14. In other words, even though there is no reception signal on channel 14, the channel 14 is in a receiving state. As described above, since the time constant is large, if the automatic channel selection operation is made faster, there is a drawback that incorrect channel selection may occur.
この発明は以上の点に鑑み、このような問題を解決する
と共にかかる欠点を除去すべくなされたもので、その目
的は自動選局動作あるいは手動選局動作が速く行なわれ
たときにも誤選局をおこすことがなく、確実に受信する
ことができる電子同調式受信装置を提供することにある
。このような目的を達成するため、この発明は、中間周
波増幅回路の出力端と高周波増幅回路の制呻入力端との
間に介挿されかつ信号入力を検波するダイオードに一端
が接続された抵抗およびこの抵抗の他端に接続されたコ
ンデンサからなるＣＲ時定数回路とこのＣＲ時定数回路
の時定数を可変設定するンイツチとを有し信号系の利得
制闘時定数を変え得る利得制（財）時定数回路と、総合
制呻回路の出力側に接続され出力によつて上記利得制薗
時定数回路のスイツチを制（財）する１駆動回路とを備
え、自動選局または手動選局の選局動作時に上記１駆動
回路の作動に基いて上記信号系の利得制（財）時定数回
路を制両し、受信信号聴取するときの時定数よりも小さ
くすることができるようにしたものである。In view of the above points, the present invention was made to solve such problems and eliminate such drawbacks, and its purpose is to prevent erroneous selection even when automatic or manual channel selection is performed quickly. It is an object of the present invention to provide an electronically tuned receiving device which can receive signals reliably without causing any interference. In order to achieve such an object, the present invention provides a resistor which is inserted between the output end of an intermediate frequency amplification circuit and the suppression input end of a high frequency amplification circuit, and has one end connected to a diode for detecting signal input. It has a CR time constant circuit consisting of a capacitor connected to the other end of this resistor, and a switch for variably setting the time constant of this CR time constant circuit. ) A time constant circuit and a drive circuit connected to the output side of the general control circuit and controlling the switch of the gain control time constant circuit by the output, and is capable of automatic tuning or manual tuning. During channel selection, the gain control (incorporated) time constant circuit of the signal system is controlled based on the operation of the first drive circuit, so that the time constant can be made smaller than the time constant when listening to the received signal. be.
以下、図面に基づきこの発明の実施例を詳細に説明する
。Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
第４図はこの発明に係る電子同調式受信装置の一実施例
を示すプロツク図である。FIG. 4 is a block diagram showing an embodiment of an electronically tuned receiver according to the present invention.
この第４図において第１図と同一符号のものは相当部分
を示し、１２はその詳細な回路を第５図に示すように、
検波および時定数を変更できる利得制両時定数（ＡＧＣ
ループフイルタ）回路、１３は総合制（財）回路１０の
出力を入力とし、その出力によつて利得制御時定数回路
１２の時定数を変化させる駆動回路で、リレーまたはス
イツチを５駆動させるため増幅回路、例えば、トランジ
スタと抵抗またはＩＣより構成され、総合制御回路１０
、例えばマイクロコンピユータからの指令信号によつて
利得制御時定数回路１２の時定数を変化させるように構
成されている。なお、第５図に示す利得制圓時定数（Ａ
ＧＣループフイルタ）回路１２において、１２ａは入力
端子、１２ｂは信号入力を検波する検波用ダイオード、
１２ｃは抵抗、１２ｄはコンデンサ、１２ｅはＡＧＣ（
自動利得制御）電圧を出力する出力端子、１２ｆは抵抗
１２ｃを短絡あるいは抵抗値を小さくするためのスイツ
チであり、このスイツチ１２ｆは駆動回路１３の出力に
よつて制御されるように構成されている。In FIG. 4, the same reference numerals as in FIG. 1 indicate corresponding parts, and 12 represents the detailed circuit as shown in FIG.
Gain-controlled time constant (AGC) that allows you to change the detection and time constant
The loop filter circuit 13 is a drive circuit that receives the output of the general control circuit 10 as an input and changes the time constant of the gain control time constant circuit 12 according to the output. The general control circuit 10 is composed of a circuit, for example, a transistor, a resistor, or an IC.
For example, the time constant of the gain control time constant circuit 12 is changed by a command signal from a microcomputer. Note that the gain control circle time constant (A
In the GC loop filter) circuit 12, 12a is an input terminal, 12b is a detection diode for detecting signal input,
12c is a resistor, 12d is a capacitor, 12e is an AGC (
The output terminal 12f that outputs the voltage (automatic gain control) is a switch for shorting the resistor 12c or reducing the resistance value, and this switch 12f is configured to be controlled by the output of the drive circuit 13. .
なお、この第５図においては、スイツチ１２ｆによつて
抵抗１２ｃの一部を短絡または開放する場合を例にとつ
て示したが、コンデンサ１２ｄを複数の直列接続された
コンデンサとし、スイツチ１２ｆによつてこのコンデン
サの一部を短絡または開放し、ＣＲ時定数回路の時定数
を可変設定するようにすることもできる。In addition, although FIG. 5 shows an example in which a part of the resistor 12c is short-circuited or opened by the switch 12f, the capacitor 12d is a plurality of capacitors connected in series, and the switch 12f is used to short-circuit or open a part of the resistor 12c. It is also possible to short-circuit or open a part of the capacitor, thereby variably setting the time constant of the CR time constant circuit.
次に、上記構成に係る電子同調式受信装置の動作につい
て第４図を参照して説明する。Next, the operation of the electronically tuned receiver having the above configuration will be explained with reference to FIG. 4.
すず、アンテナ１に受信された信号波は受信機の同調周
波数と一致しているとき、この信号波は高周波増幅回路
２で増幅されたのち、混合回路３において、局部発振器
７から入力す″る局部発振周波数と混合され、中間周波
となる。When the signal wave received by the antenna 1 matches the tuning frequency of the receiver, this signal wave is amplified by the high frequency amplifier circuit 2 and then input from the local oscillator 7 to the mixing circuit 3. It is mixed with the local oscillation frequency and becomes an intermediate frequency.
そして、中間周波増幅回路４に入力した中間周波の・一
部は信号検知回路９に入力し、出力検知動作を行ない、
総合制両回路１０および同調周波数制鐸回路８を介して
高周波増幅回路２の同調周波数および局部発振器７の発
振周波数を固定する。一方、前記中間周波増幅回路４を
通過した信号の一部は利得制両時定数回路１２に入力し
、その出力信号によつて高周波増幅回路２の利得可変回
路を動作し、中間周波増幅回路４の信号出力レベルを一
定にするように制御する。また、中間周波増幅回路４の
出力の残りの信号波は音声周波増幅回路５を通つてスピ
ーカ６に入り、音声として出力される。次に、放送信号
波を自動選局あるいは手動選局を行なう選局動作中では
駆動回路１３が動作する。Then, a part of the intermediate frequency input to the intermediate frequency amplification circuit 4 is input to the signal detection circuit 9, and an output detection operation is performed.
The tuning frequency of the high frequency amplifier circuit 2 and the oscillation frequency of the local oscillator 7 are fixed via the comprehensive damping circuit 10 and the tuned frequency damping circuit 8. On the other hand, a part of the signal that has passed through the intermediate frequency amplification circuit 4 is input to the gain control time constant circuit 12, and the output signal operates the variable gain circuit of the high frequency amplification circuit 2. control to keep the signal output level constant. Further, the remaining signal wave output from the intermediate frequency amplification circuit 4 passes through the audio frequency amplification circuit 5, enters the speaker 6, and is output as audio. Next, the drive circuit 13 operates during a tuning operation in which broadcast signal waves are automatically tuned or manually tuned.
このため、利得制御時定数（ＡＧＣループフイルタ）回
路１２のスイツチ１２ｆが閉じる。このため、利得制鐸
時定数回路１２の時定数が小さくなり、ＡＧＣ制哩立上
り時間が小さくなる。このため、選局動作を早くしても
、回路の飽和現象による誤選局を防止することができる
。なお、選局動作終了後は利得制薗時定数（ＡＧＣルー
プフイルタ）回路１２のスイツチ１２ｆが開き、普通の
受信状態とすることができ、正常な信号の再生に可能に
なる。Therefore, the switch 12f of the gain control time constant (AGC loop filter) circuit 12 is closed. Therefore, the time constant of the gain control time constant circuit 12 becomes small, and the AGC control rise time becomes short. Therefore, even if the channel selection operation is made faster, incorrect channel selection due to circuit saturation can be prevented. Incidentally, after the channel selection operation is completed, the switch 12f of the gain control time constant (AGC loop filter) circuit 12 is opened, and a normal reception state can be established, allowing normal signal reproduction.
上記説明と同様時定数を決定するコンデンサーを２個以
上使用する場合、その一部を選局動作中スイツチを開く
ことで時定数を小さく同様の効果をあげることも出来る
。以上、詳細に説明したように、この発明に係る電子同
調式受信装置によれば自動選局動作あるいは手動選局動
作が速く行なわれたときにも誤選局をおこすことがなく
、確実に受信することができる効果がある。Similar to the above explanation, if two or more capacitors are used to determine the time constant, the same effect can be obtained by reducing the time constant by opening the switch of some of them during the channel selection operation. As explained above in detail, the electronic tuning type receiving device according to the present invention prevents erroneous channel selection even when automatic tuning operation or manual tuning operation is performed quickly, and ensures reliable reception. There is an effect that can be done.
第１図は従来の電子同調式受信機を示すプロツク図、第
２図は第１図のＡ点からＢ点に至る間の各チヤンネルま
たは周波数に同調させたときの周波数一選択特姓群を示
す図、第３図は第１図の利得制（財）時定数（ＡＧＣル
ープフイルタ）回路を示す回路図、第４図はこの発明に
係る電子同調式受信装置の一実施例を示すプロック図、
第５図は第４図の利得制（財）時定数（ＡＧＣループフ
イルタ）回路を示す回路図である。
１・・・・・・アンテナ、２・・・・・・高周波増幅回
路、３・・・・・・混合回路、４・・・・・・中間周波
増幅回路、５・・・・・・音声周波増幅回路、６・・・
・・・スピーカ、７・・・・・・局部発振器、８・・・
・・・同調周波数制両回路、９・・・・・・信号検知回
路、１０・・・・・・総台制哩回路、１１・・・・・・
利得制凪時定数（ＡＧＣループフイルタ）回路、１１ａ
・・・・・・入力端子、１１ｂ・・・・・・ダイオード
、１１ｃ・・・・・・抵抗、１１ｄ・・・・・・コンデ
ンサ、１１ｅ・・・・・・出力端子、１２・・・・・・
利得制両時定数（ＡＧＣループフイルタ）回路、１２ａ
・・・・・・人力端子、１２ｂ・・・・・・検波用ダイ
オード、１２ｃ・・・・・・抵抗、１２ｄ・・・・・・
コンデンサ、１２ｅ・・・・・・出力端子、１２ｆ・・
・・・・スイツチ、１３・・・・・・駆動回路。Figure 1 is a block diagram showing a conventional electronically tuned receiver, and Figure 2 shows a group of frequency selection characteristics when tuned to each channel or frequency from point A to point B in Figure 1. FIG. 3 is a circuit diagram showing the gain-controlled time constant (AGC loop filter) circuit of FIG. 1, and FIG. 4 is a block diagram showing an embodiment of the electronically tuned receiver according to the present invention. ,
FIG. 5 is a circuit diagram showing the gain-based time constant (AGC loop filter) circuit of FIG. 4. 1...Antenna, 2...High frequency amplification circuit, 3...Mixing circuit, 4...Intermediate frequency amplification circuit, 5...Audio Frequency amplification circuit, 6...
...Speaker, 7...Local oscillator, 8...
... Tuned frequency control circuit, 9 ... Signal detection circuit, 10 ... Total control circuit, 11 ...
Gain control calm time constant (AGC loop filter) circuit, 11a
...Input terminal, 11b...Diode, 11c...Resistor, 11d...Capacitor, 11e...Output terminal, 12... ...
Gain-controlled time constant (AGC loop filter) circuit, 12a
......Manual terminal, 12b...Detection diode, 12c...Resistor, 12d...
Capacitor, 12e...Output terminal, 12f...
...Switch, 13... Drive circuit.
Claims (1)
可変回路を含む高周波増幅回路で増幅した後混合回路に
加え、局部発振器からの局部発振周波数と混合して中間
周波信号に変換し、その中間周波信号を同調回路を含む
中間周波増幅回路に入力すると共に出力検知動作を行う
信号検知回路に入力し、この信号検知回路の出力を総合
制御回路および同調周波数制御回路を介して前記高周波
増幅回路および前記局部発振器に加え該高周波増幅回路
の同調周波数および該局部発振器の発振周波数を制御し
て固定するようにした電子同調式ラジオ受信機または無
線機などの電子同調式受信装置において、前記中間周波
増幅回路の出力端と前記高周波増幅回路の制御入力端と
の間に介挿されかつ信号入力を検知するダイオードに一
端が接続された抵抗およびこの抵抗の他端に接続された
コンデンサからなるＣＲ時定数回路とこのＣＲ時定数回
路の時定数を可変設定するスイッチとを有し信号系の利
得制御時定数を変え得る利得制御時定数回路と、前記総
合制御回路の出力側に接続され出力によつて前記利得制
御時定数回路のスイッチを制御する駆動回路とを備え、
自動選局または手動選局の選局動作時に前記駆動回路の
作動に基いて前記信号系の利得制御時定数回路を制御し
、受信信号聴取するときの時定数よりも小さくし得るよ
うにしたことを特徴とする電子同調式受信装置。1 The received signal from the antenna is amplified by a high frequency amplifier circuit including a variable tuning circuit and a variable gain circuit, then added to a mixing circuit, mixed with the local oscillation frequency from a local oscillator, converted to an intermediate frequency signal, and the intermediate frequency signal is input to an intermediate frequency amplification circuit including a tuning circuit, and is also input to a signal detection circuit that performs an output detection operation, and the output of this signal detection circuit is transmitted to the high frequency amplifier circuit and the local section via a general control circuit and a tuning frequency control circuit. In an electronically tuned receiving device such as an electronically tuned radio receiver or radio device, which controls and fixes the tuning frequency of the high frequency amplifier circuit and the oscillation frequency of the local oscillator in addition to the oscillator, the intermediate frequency amplifier circuit a CR time constant circuit consisting of a resistor interposed between the output terminal and the control input terminal of the high frequency amplifier circuit and having one end connected to a diode for detecting signal input, and a capacitor connected to the other end of the resistor; a gain control time constant circuit having a switch for variably setting the time constant of the CR time constant circuit and capable of changing the gain control time constant of the signal system; and a drive circuit that controls the switch of the control time constant circuit,
The gain control time constant circuit of the signal system is controlled based on the operation of the drive circuit during automatic tuning or manual tuning operation, so that the time constant can be made smaller than the time constant when listening to a received signal. An electronic tuning receiving device characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6916279A JPS5941605B2 (en) | 1979-05-30 | 1979-05-30 | electronic tuning receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6916279A JPS5941605B2 (en) | 1979-05-30 | 1979-05-30 | electronic tuning receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55159619A JPS55159619A (en) | 1980-12-11 |
| JPS5941605B2 true JPS5941605B2 (en) | 1984-10-08 |
Family
ID=13394720
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6916279A Expired JPS5941605B2 (en) | 1979-05-30 | 1979-05-30 | electronic tuning receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5941605B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57186822A (en) * | 1981-05-13 | 1982-11-17 | Matsushita Electric Ind Co Ltd | Automatic channel searching device |
| JPH0635557Y2 (en) * | 1984-10-16 | 1994-09-14 | 三洋電機株式会社 | AGC circuit |
-
1979
- 1979-05-30 JP JP6916279A patent/JPS5941605B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55159619A (en) | 1980-12-11 |
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