JPS61222326A - Receiver - Google Patents
ReceiverInfo
- Publication number
- JPS61222326A JPS61222326A JP6278885A JP6278885A JPS61222326A JP S61222326 A JPS61222326 A JP S61222326A JP 6278885 A JP6278885 A JP 6278885A JP 6278885 A JP6278885 A JP 6278885A JP S61222326 A JPS61222326 A JP S61222326A
- Authority
- JP
- Japan
- Prior art keywords
- mixer
- intermediate frequency
- input level
- level
- output
- 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
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/26—Circuits for superheterodyne receivers
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Superheterodyne Receivers (AREA)
- Noise Elimination (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明は干渉検出器を備えた受信機に係り、特に高い受
信入力レベルまで干渉検出が可能な受信機に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a receiver equipped with an interference detector, and particularly to a receiver capable of detecting interference up to a high reception input level.
従来、この種の受信機は第３図に示す如き構成を有した
。即ち受信機入力端子１により入力された信号は、高周
波増幅器２により増幅され、第１局部発振回路３からの
第１局部発振出力と、第１混合器４により混合され、第
１中間周波数フィル−タ５を通過した後、第２局部発振
回路６からの第２局部発振出力と第２混合器７により混
合され、第２中間周波数フィルタ８を通過する。該第２
中間周波数フィルタ８の第２中間周波数信号Ｔは後続す
る回路（図示せず）に入力されるとともにその一部が干
渉検出器９に入力される。Conventionally, this type of receiver has had a configuration as shown in FIG. That is, the signal input through the receiver input terminal 1 is amplified by the high frequency amplifier 2, mixed with the first local oscillation output from the first local oscillation circuit 3 by the first mixer 4, and then sent to the first intermediate frequency filter. After passing through the filter 5, the signal is mixed with the second local oscillation output from the second local oscillation circuit 6 by a second mixer 7, and then passes through a second intermediate frequency filter 8. The second
The second intermediate frequency signal T of the intermediate frequency filter 8 is input to a subsequent circuit (not shown), and a portion thereof is input to the interference detector 9 .
本受信機においては同時に周波数の略等しい２波の電波
を受信した場合に２波の周波数の差によって生じるうな
り（ビート）周波数（ＡＭ周波数）と２波の信号レベル
の差（Ｄ／Ｖ比）によって生じるうなりの大きさくＡＭ
変調度）とを干渉検出器９によって検出する。When this receiver receives two radio waves with approximately the same frequency at the same time, the beat frequency (AM frequency) caused by the difference in the frequencies of the two waves and the difference in signal level between the two waves (D/V ratio) The magnitude of the beat caused by AM
modulation degree) is detected by the interference detector 9.
ところで干渉検出はより高い受信入力レベルに対して行
われることが望まれる。ところが、干渉検出をより高い
受信入力レベルまで行うには、より高い受信入力レベル
まで高周波増幅器２、第１混合器４、第２混合器７を飽
和しないようにする必要があるが、高周波増幅器２及び
第１混合器４及び第２混合器７はそれぞれ適当な利得が
あり、この中で一番小さい受信入力レベルで最初に飽和
するのは第２混合器７であった。Incidentally, it is desired that interference detection be performed at a higher received input level. However, in order to perform interference detection up to a higher reception input level, it is necessary to prevent the high frequency amplifier 2, first mixer 4, and second mixer 7 from becoming saturated even at a higher reception input level. The first mixer 4 and the second mixer 7 each have an appropriate gain, and among them, the second mixer 7 saturates first at the lowest received input level.
第２図（（１）は受信入力レベルと、第２混合器７の第
２中間周波数成分出力レベルとの関係を表わすグラフで
あり、第２図（ｂ）は受信入力レベルと、干渉検出器９
の出力レベルとの関係を表わすグラフである。同図にお
いて一点鎖線で示すものが従来の受信機に関するもので
ある。FIG. 2 ((1) is a graph showing the relationship between the received input level and the second intermediate frequency component output level of the second mixer 7, and FIG. 2(b) is a graph showing the relationship between the received input level and the interference detector 9
It is a graph showing the relationship between the output level and the output level. In the figure, what is indicated by a dashed line is related to a conventional receiver.
同図（（１）においてＳは、第２混合器７の第２中間周
波数成分の飽和レベルである。同図に示す如く、受信入
力レベルがＶｌになると第２混合器７の第２中間周波数
成分は飽和レベルＳに達するため同図（ｂ）に示す様に
干渉検出器９の出力は、受信入力レベルｖｌで急激に下
がり、受信入力レベルＶ１以上の干渉検出は行えない。In the figure ((1), S is the saturation level of the second intermediate frequency component of the second mixer 7. As shown in the figure, when the receiving input level becomes Vl, the second intermediate frequency component of the second mixer 7 Since the component reaches the saturation level S, the output of the interference detector 9 sharply decreases at the received input level Vl, as shown in FIG.
このように従来の受信機では第２混合器７の第２中間周
波数成分が低い受信入力レベルで飽和する為、干渉検出
も高い受信入力レベルでは行えないという問題があった
。As described above, in the conventional receiver, since the second intermediate frequency component of the second mixer 7 is saturated at a low reception input level, there is a problem in that interference detection cannot be performed at a high reception input level.
そこで本発明の目的は前記問題点を解決すべく高い受信
入力レベルにおいても干渉検出を行うことができる受信
機を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a receiver capable of detecting interference even at a high reception input level in order to solve the above-mentioned problems.
本発明は前記目的を達成すべく第１中間周波数フィルタ
と第２混合器の間に可変減衰器を設け、＠２中間周波数
フィルタの出力を検出し、この出力に応じて可変減衰器
の減衰量を変えることにより可変減衰器の最大減衰量だ
け高い受信入力レベルまで干渉検出（ＡＭ検出）を可能
にしたものである。In order to achieve the above object, the present invention provides a variable attenuator between the first intermediate frequency filter and the second mixer, detects the output of the @2 intermediate frequency filter, and adjusts the attenuation amount of the variable attenuator according to this output. By changing , interference detection (AM detection) is made possible up to a reception input level that is higher by the maximum attenuation of the variable attenuator.
以下図面ζこ基づいて本発明の実施例を具体的かつ詳細
に説明する。Embodiments of the present invention will be described in detail below with reference to the drawings.
第１図は本発明の１実施例に係る受信機の要部の構成を
示すブロック図であり同図において第３図に示す従来の
受信機と同一の機能を果たす要素には同一の番号を付す
る。FIG. 1 is a block diagram showing the configuration of the main parts of a receiver according to an embodiment of the present invention. In the figure, elements that perform the same functions as those of the conventional receiver shown in FIG. 3 are designated by the same numbers. Attach.
本実施例では、第１中間周波数フィルタ５と、第２混合
器７との間に可変減衰器１０を設け、第２中間周波数フ
ィルタ８の出力を増幅器１１、検波器１２を介して可変
減衰器１０に入力する。In this embodiment, a variable attenuator 10 is provided between the first intermediate frequency filter 5 and the second mixer 7, and the output of the second intermediate frequency filter 8 is passed through the amplifier 11 and the detector 12 to the variable attenuator 10. Enter 10.
増幅器１１、及び検波器１２は、第２中間周波数フィル
タの出力を検出し、この出力信号に応じ可変減衰器１０
の減衰量を変えるものである。The amplifier 11 and the detector 12 detect the output of the second intermediate frequency filter, and depending on this output signal, the variable attenuator 10
This changes the amount of attenuation.
次に本実施例の動作について説明する。本実施例におい
ては、第２中間周波数フィルタ８の第２中間周波数信号
Ｔを増幅器１１で増幅し、検波器１２で検出し、この信
号で可変減衰器１０の減衰量を制御する。Next, the operation of this embodiment will be explained. In this embodiment, the second intermediate frequency signal T of the second intermediate frequency filter 8 is amplified by the amplifier 11 and detected by the detector 12, and the attenuation amount of the variable attenuator 10 is controlled using this signal.
第２図（ａハこおいてＡは可変減衰器１０の最小の減衰
量を示し、Ｂは最大の減衰量を表わす。In FIG. 2 (a), A indicates the minimum attenuation amount of the variable attenuator 10, and B indicates the maximum attenuation amount.
同図Ｃ（１）の受信入力レベルは増幅器１１、検波器１
２で検出される。受信入力レベルがｖ１以下では可変減
衰器の減衰量が最小になるよう、又、受信入力レベルが
Ｖｌを越えた時点で可変減衰器の減衰量が最大になるよ
うに可変減衰器１ｏの減衰量が制御されるとする。The receiving input level of C(1) in the same figure is amplifier 11 and detector 1.
Detected at 2. The attenuation amount of the variable attenuator 1o is set so that the attenuation amount of the variable attenuator becomes the minimum when the reception input level is below V1, and the attenuation amount of the variable attenuator becomes the maximum when the reception input level exceeds Vl. is controlled.
この場合、受信機の受信入力レベルと第２混合器の出力
は同図（（１）で実線で示す如きものとなり受信入力レ
ベルがｖｌになっても第２混合器の第２中間周波数成分
は飽和せず、受信入力レベルがｖ８になってはじめて第
２混合器の第２中間周波数成分の出力が飽和レベルに達
する。In this case, the receiving input level of the receiver and the output of the second mixer will be as shown by the solid line in Figure (1), and even if the receiving input level becomes vl, the second intermediate frequency component of the second mixer will be It is not saturated, and the output of the second intermediate frequency component of the second mixer reaches the saturation level only when the received input level reaches v8.
しかして干渉検出器９も第２図Φ）の実線に示す如く、
受信入力レベルがＶｌに達するまで作動することとなる
。As shown by the solid line in FIG. 2 Φ), the interference detector 9 is also
It will operate until the receiving input level reaches Vl.
〔発明の効果〕
以上説明した如く、本発明によれば従来の受信機の受信
入力レベルに比して可変減衰器の減衰量だけ高い受信入
力レベルまで干渉検出を行うことが出来、より高い受信
入力レベルまで干渉検出を行うことができる。[Effects of the Invention] As explained above, according to the present invention, it is possible to perform interference detection up to a reception input level that is higher than the reception input level of a conventional receiver by the amount of attenuation of the variable attenuator, resulting in higher reception. Interference detection can be performed down to the input level.
第１図は本発明の１実施例に係る受信機の要部の構成を
示すブロック図、第２図（（１）は受信入力しベルと第
２混合器の第２中間周波数成分出力レベルとの関係を示
すグラフ、第２図の）は受信入力レベルと干渉検出器の
出力レベルとの関係を示すグラフ、第３図は従来の受信
機の要部の構成を示すブロック図である。
１・−・受信機入力端子、２・・・高周波増幅器、３・
・・第１局部発振回路、４・・・第１混合器、５・・・
第１中間周波数フィルタ、６・・・第２局部発振回路、
７・・・第２混合器、８・・・第２中間周波数フィルタ
、９・・・干渉検出器、１０−・・可変減衰器、１１・
・・増幅器、１２・−検波器。
第１図FIG. 1 is a block diagram showing the configuration of the main parts of a receiver according to an embodiment of the present invention, and FIG. FIG. 2 is a graph showing the relationship between the received input level and the output level of the interference detector. FIG. 3 is a block diagram showing the configuration of the main parts of a conventional receiver. 1... Receiver input terminal, 2... High frequency amplifier, 3...
...first local oscillation circuit, 4...first mixer, 5...
first intermediate frequency filter, 6... second local oscillation circuit,
7... Second mixer, 8... Second intermediate frequency filter, 9... Interference detector, 10-... Variable attenuator, 11...
...Amplifier, 12.-Detector. Figure 1
Claims (1)
器および第２中間周波数フィルタを具え、前記第２中間
周波数フィルタの出力により干渉検出を行う受信機にお
いて、 前記第１中間周波数フィルタと前記第２混合器の間に可
変減衰器を設け、前記第２中間周波数フィルタの出力に
応じて、前記可変減衰器の減衰量を制御することを特徴
とする受信機。(1) A receiver that includes a first mixer, a first intermediate frequency filter, a second mixer, and a second intermediate frequency filter, and performs interference detection using the output of the second intermediate frequency filter, the first intermediate frequency filter and the second mixer, a variable attenuator is provided between the receiver and the second mixer, and the amount of attenuation of the variable attenuator is controlled according to the output of the second intermediate frequency filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6278885A JPS61222326A (en) | 1985-03-27 | 1985-03-27 | Receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6278885A JPS61222326A (en) | 1985-03-27 | 1985-03-27 | Receiver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61222326A true JPS61222326A (en) | 1986-10-02 |
Family
ID=13210433
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6278885A Pending JPS61222326A (en) | 1985-03-27 | 1985-03-27 | Receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61222326A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0716512A1 (en) | 1994-12-05 | 1996-06-12 | Hitachi, Ltd. | Radio receiver |
-
1985
- 1985-03-27 JP JP6278885A patent/JPS61222326A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0716512A1 (en) | 1994-12-05 | 1996-06-12 | Hitachi, Ltd. | Radio receiver |
| US5930695A (en) * | 1994-12-05 | 1999-07-27 | Hitachi, Ltd. | Radio receiver with amplitude limiter prior to mixer and band limiting filter |
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