JPH0150145B2 - - Google Patents
Info
- Publication number
- JPH0150145B2 JPH0150145B2 JP56158811A JP15881181A JPH0150145B2 JP H0150145 B2 JPH0150145 B2 JP H0150145B2 JP 56158811 A JP56158811 A JP 56158811A JP 15881181 A JP15881181 A JP 15881181A JP H0150145 B2 JPH0150145 B2 JP H0150145B2
- Authority
- JP
- Japan
- Prior art keywords
- circuits
- circuit
- detection
- signal
- component
- 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
- 238000001514 detection method Methods 0.000 claims description 15
- 239000000284 extract Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 description 5
- 230000007257 malfunction Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
- H04B7/0802—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection
- H04B7/0817—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with multiple receivers and antenna path selection
- H04B7/082—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using antenna selection with multiple receivers and antenna path selection selecting best antenna path
Description
【発明の詳細な説明】
本発明はスペースダイバシテイ方式に関し、詳
しくは例えばカーラジオにおけるFMマルチパス
ノイズの低減回路に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a space diversity system, and more particularly to a circuit for reducing FM multipath noise in a car radio, for example.
従来のFMマルチパスノイズの抵減法として
は、第１図に示すように、中間周波回路３よりキ
ヤリア信号を取り出し、該キヤリアレベルによつ
て、FMマルチブレツクス５のステレオセパレー
シヨンと、高域の周波数特性を下げ、マルチパス
ノイズを聴感的に緩和するものがある。 As shown in Fig. 1, the conventional method for reducing FM multipath noise involves extracting a carrier signal from the intermediate frequency circuit 3, and depending on the carrier level, the stereo separation of the FM multiplex 5 and the high frequency There are some methods that lower the frequency characteristics of the signal to audibly alleviate multipath noise.
しかし、この方法では、マルチパスノイズが、
完全には、キヤリアレベルの変化に対応していな
いため、マルチパスノイズを完全になくすことは
できないという欠点があつた。 However, with this method, multipath noise
However, it has the disadvantage that multipath noise cannot be completely eliminated because it does not respond to changes in the carrier level.
本発明の目的は上記した従来技術の欠点をなく
し、マルチパスノイズを低減するためのスペース
ダイバシテイ方式の制御方式を提供することにあ
る。 SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a space diversity control method for reducing multipath noise.
マルチパスノイズの発生時には、キヤリアレベ
ルの変化の他に、中間周波信号に、AM変調成分
が発生する。従つてこのAM成分を検出し、スペ
ースダイバシテイ方式の制御信号として、２系統
の受信回路を切換えれば、マルチパスノイズ除去
に効果がある。 When multipath noise occurs, in addition to changes in the carrier level, AM modulation components are generated in the intermediate frequency signal. Therefore, if this AM component is detected and used as a control signal for the space diversity method to switch between the two receiving circuits, multipath noise can be effectively removed.
以下、本発明の実施例を第２図により説明す
る。この回路は、２つの受信回路Ａ，A′から成
り、該受信回路の検波回路４，４′の検波出力信
号は夫々信号切換回路１２に供給され、該回路に
て一方の検波出力信号が選択されて後段の出力回
路に導かれる。また中間周波回路３，３′の中間
周波信号はAM検波回路８，８′により、AM検
波されてその出力にはAM変調成分のみが取り出
される。このAM変調成分はバンドパスフイルタ
９，９′に供給され、該フイルタにて19KHz成分
のみを取り出される。この出力信号は整流回路１
０，１０′にて整流され、次段の比較回路１１に
てそのレベルを比較され、比較回路１１はこの時
AM変調成分の小さい側の受信回路の信号を出力
回路に導く如く上記信号切換回路を制御する信号
を出力する。 Embodiments of the present invention will be described below with reference to FIG. This circuit consists of two receiving circuits A and A', and the detection output signals of the detection circuits 4 and 4' of the receiving circuits are respectively supplied to a signal switching circuit 12, and one of the detection output signals is selected by the circuit. and then guided to the subsequent output circuit. Further, the intermediate frequency signals of the intermediate frequency circuits 3 and 3' are subjected to AM detection by the AM detection circuits 8 and 8', and only the AM modulation component is extracted as an output. This AM modulation component is supplied to bandpass filters 9 and 9', and only the 19KHz component is extracted by the filter. This output signal is the rectifier circuit 1
0 and 10', and their levels are compared in the next stage comparator circuit 11. At this time, the comparator circuit 11
A signal is output for controlling the signal switching circuit so as to guide the signal of the receiving circuit having the smaller AM modulation component to the output circuit.
要するに本発明はマルチパスノイズ発生時に発
生する成分を取り出し、この成分を利用して信号
切換回路の切換えを制御してなるものである。こ
こで中間周波信号のAM変調成分には、マルチパ
スによつて生じる成分以外の雑音も入つているこ
とから誤動作が発生する。しかしマルチパスノイ
ズがステレオ放送時に特に顕著であることを考え
て、このAM成分のうち、ステレオパイロツト信
号である19KHzのAM成分を取り出し、これを制
御信号としている上記実施例によれば、誤動作は
解消できる。 In short, the present invention extracts a component generated when multipath noise occurs and uses this component to control switching of a signal switching circuit. Here, malfunctions occur because the AM modulation component of the intermediate frequency signal contains noise other than components caused by multipath. However, considering that multipath noise is particularly noticeable during stereo broadcasting, the above embodiment extracts the 19KHz AM component, which is the stereo pilot signal, from among the AM components and uses this as the control signal. It can be resolved.
以上述べて本発明によれば、従来、キヤリアレ
ベルを制御信号としていたため、マルチパスノイ
ズの発生時にキヤリアレベルが変化しない場合に
誤動作していたが、本発明は、マルチパスノイズ
発生時に発生するAM変調成分を制御信号とし
て、２つの受信回路を切換え、歪のない電波を受
信することができるので、スペースダイバシテイ
方式として、誤動作なく、マルチパスノイズを低
減できるという効果がある。 As described above, according to the present invention, since the carrier level was conventionally used as a control signal, malfunctions occurred when the carrier level did not change when multipath noise occurred, but the present invention can prevent malfunctions when the carrier level does not change when multipath noise occurs. Since the two receiving circuits can be switched using the AM modulation component as a control signal and receive undistorted radio waves, the space diversity method has the effect of reducing multipath noise without malfunction.
第１図は従来のセパレーシヨン制御回路の、ブ
ロツク図、第２図は本発明の一実施例を示すスペ
ースダイバシテイ方式のブロツク図である。
１……アンテナ、２……FMフロントエンド、
３……IF回路、４……検波回路、５……FMマル
チ回路、６……オーデイオ回路、７……スピーカ
ー、８……AM検波回路、９……19KHzバンドパ
スフイルタ、１０……倍電圧整流回路、１１……
比較回路、１２……切換回路、１′……サブアン
テナ、２′……サブフロントエンド、３′……サブ
IF回路、４′……サブ検波回路、８′……サブAM
検波回路、９′……サブ19KHzバンドパスフイル
タ、１０′……サブ倍電圧整流回路。
FIG. 1 is a block diagram of a conventional separation control circuit, and FIG. 2 is a block diagram of a space diversity system showing one embodiment of the present invention. 1...Antenna, 2...FM front end,
3...IF circuit, 4...Detection circuit, 5...FM multi circuit, 6...Audio circuit, 7...Speaker, 8...AM detection circuit, 9...19KHz band pass filter, 10...Voltage doubler Rectifier circuit, 11...
Comparison circuit, 12...Switching circuit, 1'...Sub antenna, 2'...Sub front end, 3'...Sub
IF circuit, 4'...Sub detection circuit, 8'...Sub AM
Detection circuit, 9'...Sub 19KHz band pass filter, 10'...Sub voltage doubler rectifier circuit.
Claims (1)
信回路の出力を切換選択して出力回路に導く信号
切換回路と、上記第１、第２の受信回路に結合さ
れマルチパスノイズによつて生じるAM変調成分
を抽出する第１、第２のAM変調成分検出回路
と、該第１、第２のAM変調成分検出回路に結合
され、該両AM変調成分のレベルを比較し、上記
信号切換回路を上記第１、第２の受信回路の上記
AM変調成分の小さい側に切換える制御信号を出
力する比較器とからなることを特徴とするスペー
スダイバシテイ受信方式。 ２ 上記第１、第２のAM変調成分検出回路は上
記第１、第２の受信回路の中間周波信号をAM検
波する第１、第２の検波回路と、該第１、第２の
検波回路の検波出力からステレオパイロツト信号
（19KHz）のAM成分を抽出する第１、第２のバ
ンドパスフイルタと、該フイルタをパスしたAM
成分を整流する第１、第２の整流回路からなるこ
とを特徴とする特許請求の範囲第１項記載のスペ
ースダイバシテイ受信方式。[Scope of Claims] 1: first and second receiving circuits; a signal switching circuit that switches and selects the outputs of the first and second receiving circuits and guides them to the output circuit; and the first and second receiving circuits. first and second AM modulation component detection circuits that are coupled to the circuit and extract AM modulation components caused by multipath noise; and The levels of the components are compared, and the signal switching circuit is switched between the first and second receiving circuits.
A space diversity reception system characterized by comprising a comparator that outputs a control signal to switch to the side with a smaller AM modulation component. 2 The first and second AM modulation component detection circuits include first and second detection circuits that perform AM detection on the intermediate frequency signals of the first and second reception circuits, and the first and second detection circuits. A first and second bandpass filter extracts the AM component of the stereo pilot signal (19KHz) from the detection output of the
2. The space diversity reception system according to claim 1, comprising first and second rectifier circuits that rectify the components.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56158811A JPS5860839A (en) | 1981-10-07 | 1981-10-07 | Space diversity reception system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56158811A JPS5860839A (en) | 1981-10-07 | 1981-10-07 | Space diversity reception system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5860839A JPS5860839A (en) | 1983-04-11 |
| JPH0150145B2 true JPH0150145B2 (en) | 1989-10-27 |
Family
ID=15679871
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56158811A Granted JPS5860839A (en) | 1981-10-07 | 1981-10-07 | Space diversity reception system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5860839A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0779298B2 (en) * | 1987-11-05 | 1995-08-23 | 松下電器産業株式会社 | Receiver |
-
1981
- 1981-10-07 JP JP56158811A patent/JPS5860839A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5860839A (en) | 1983-04-11 |
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