JPS6214976B2 - - Google Patents
Info
- Publication number
- JPS6214976B2 JPS6214976B2 JP9724280A JP9724280A JPS6214976B2 JP S6214976 B2 JPS6214976 B2 JP S6214976B2 JP 9724280 A JP9724280 A JP 9724280A JP 9724280 A JP9724280 A JP 9724280A JP S6214976 B2 JPS6214976 B2 JP S6214976B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- stereo
- signal
- demodulation
- wideband
- 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
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/86—Arrangements characterised by the broadcast information itself
- H04H20/88—Stereophonic broadcast systems
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Stereo-Broadcasting Methods (AREA)
Description
【発明の詳細な説明】 本発明は、AMステレオ復調器に関する。[Detailed description of the invention] The present invention relates to an AM stereo demodulator.
AMステレオ放送は主チヤンネルがAM変調、
副チヤンネルがPM変調されているが、従来の
AMステレオ復調器は、主チヤンネルＬ＋Ｒの復
調は従来のAMの復調と同様にダイオード検波を
用い、副チヤンネル信号Ｌ−Ｒの復調は被変調信
号（搬送波）を直接PM（Phase Modulation）復
調している。AMステレオ変調の副チヤンネルの
PM変調において、位相偏位は、±１ラジアン程度
であり、位相偏位が非常に小さい。従つて従来方
法の復調では、副チヤンネル信号の品質が復調器
単体のノイズおよび外乱等により大きく影響を受
ける欠点があつた。 For AM stereo broadcasting, the main channel is AM modulated.
The subchannel is PM modulated, but the conventional
The AM stereo demodulator uses diode detection to demodulate the main channel L+R, similar to conventional AM demodulation, and demodulates the sub-channel signal L-R by directly PM (Phase Modulation) demodulating the modulated signal (carrier wave). There is. AM stereo modulation subchannel
In PM modulation, the phase deviation is about ±1 radian, which is very small. Therefore, the conventional method of demodulation has the drawback that the quality of the sub-channel signal is greatly affected by noise, disturbance, etc. of the demodulator itself.
したがつて本発明の目的は、従来欠点を除いて
副チヤンネルの復調信号の品質を改善することが
できるAMステレオ復調器を提供することであ
る。 SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an AM stereo demodulator that can improve the quality of the demodulated signal of the sub-channel while eliminating the conventional drawbacks.
本発明によれば副チヤンネルの復調において、
被復調信号を周波数逓倍する広帯域逓倍器を挿入
し、逓倍された被復調信号をPM復調するAMス
テレオ復調器が得られる。 According to the present invention, in the demodulation of the sub-channel,
An AM stereo demodulator that performs PM demodulation of the multiplied demodulated signal by inserting a wideband multiplier that frequency-multiplies the demodulated signal is obtained.
次に本発明の一実施例の図面を参照して本発明
を詳細に説明する。第１図は本発明の一実施例を
示す図であり、AMステレオ変調信号は、AM復
調回路１で主チヤンネルが復調される。他方AM
ステレオ変調信号はリミツタ回路２、広帯域逓倍
回路３、フイルタ４を経てPM復調回路５へ送ら
れ、副チヤンネルが復調される。 Next, the present invention will be described in detail with reference to the drawings of an embodiment of the present invention. FIG. 1 is a diagram showing an embodiment of the present invention, in which the main channel of an AM stereo modulated signal is demodulated by an AM demodulation circuit 1. In FIG. On the other hand AM
The stereo modulation signal is sent to a PM demodulation circuit 5 via a limiter circuit 2, a wideband multiplier circuit 3, and a filter 4, where the subchannel is demodulated.
リミツタ回路２はAM成分を除くためであり、
広帯域逓倍回路３で位相偏差が拡大される。例え
ば広帯域逓倍回路３で８逓倍されると位相偏差は
±１ラジアンから±８ラジアンと拡大され、復調
時のＳ／Ｎは逓倍数分に応じて向上する。 Limiter circuit 2 is for removing AM components,
The phase deviation is amplified by the broadband multiplier circuit 3. For example, when the signal is multiplied by 8 in the wideband multiplier circuit 3, the phase deviation is expanded from ±1 radian to ±8 radian, and the S/N during demodulation improves according to the number of multiplications.
第２図は広帯域逓倍回路の構成を示す図であ
り、これは２倍逓倍を行う回路である。図で入力
は広帯域分配器６で分配されたあと、バランスミ
キサ７で混合されたあと、フイルタ８によつて逓
倍された成分が取り出される。第１図の逓倍回路
３は８倍なので、第２図のものを３段接続すれば
よい。このとき変換損失を補うために広帯域増幅
回路（図示せず）を適当に挿入する。 FIG. 2 is a diagram showing the configuration of a wideband multiplier circuit, which is a circuit that performs double multiplication. In the figure, the input is distributed by a broadband distributor 6, mixed by a balance mixer 7, and then a multiplied component is extracted by a filter 8. Since the multiplier circuit 3 shown in FIG. 1 has a multiplier of 8 times, the multiplier circuit 3 shown in FIG. 2 can be connected in three stages. At this time, a wideband amplifier circuit (not shown) is appropriately inserted to compensate for conversion loss.
本発明は、以上説明したようにAMステレオ復
調器の副チヤンネル復調を、広帯域逓倍回路によ
り周波数逓倍後復調することによりAMステレオ
復調信号の品質を改善することができ、更に広帯
域逓倍回路を使用している為逓倍段を無調整化で
きる効果がある。 As explained above, the present invention can improve the quality of an AM stereo demodulated signal by demodulating the subchannel of an AM stereo demodulator after frequency multiplication using a wideband multiplier circuit. This has the effect of eliminating the need to adjust the multiplier stage.
第１図は本発明の一実施例を示した図面、第２
図は第１図における広帯域逓倍回路を示す図。
図において、１……AM復調回路、２……リミ
ツタ、３……広帯域逓倍回路、４，８……フイル
タ、５……PM復調回路、６……広帯域分配器、
７……ミキサ。
Fig. 1 is a drawing showing one embodiment of the present invention, Fig. 2 is a drawing showing an embodiment of the present invention;
The figure is a diagram showing the wideband multiplier circuit in FIG. 1. In the figure, 1...AM demodulation circuit, 2...limiter, 3...wideband multiplier circuit, 4, 8...filter, 5...PM demodulation circuit, 6...wideband distributor,
7...Mixer.
Claims (1)
を復調する過程において、変調信号を周波数逓倍
する広帯域周波数逓倍器を具備し、前記逓倍器か
らの信号をPM復調することを特徴とするAMス
テレオ復調器。1. An AM stereo demodulator comprising a wideband frequency multiplier that frequency-multiplies a modulated signal in the process of demodulating a sub-channel signal from an AM stereo modulated signal, and performs PM demodulation on the signal from the multiplier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9724280A JPS5723345A (en) | 1980-07-16 | 1980-07-16 | Am stereo demodulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9724280A JPS5723345A (en) | 1980-07-16 | 1980-07-16 | Am stereo demodulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5723345A JPS5723345A (en) | 1982-02-06 |
| JPS6214976B2 true JPS6214976B2 (en) | 1987-04-04 |
Family
ID=14187128
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9724280A Granted JPS5723345A (en) | 1980-07-16 | 1980-07-16 | Am stereo demodulator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5723345A (en) |
-
1980
- 1980-07-16 JP JP9724280A patent/JPS5723345A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5723345A (en) | 1982-02-06 |
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