JPS5951676A - Audio detection device - Google Patents
Audio detection deviceInfo
- Publication number
- JPS5951676A JPS5951676A JP58143235A JP14323583A JPS5951676A JP S5951676 A JPS5951676 A JP S5951676A JP 58143235 A JP58143235 A JP 58143235A JP 14323583 A JP14323583 A JP 14323583A JP S5951676 A JPS5951676 A JP S5951676A
- Authority
- JP
- Japan
- Prior art keywords
- carrier wave
- sound
- audio
- carrier
- video
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
- H04N5/60—Receiver circuitry for the reception of television signals according to analogue transmission standards for the sound signals
- H04N5/62—Intercarrier circuits, i.e. heterodyning sound and vision carriers
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Television Receiver Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、インターキャリア方式のテレビジョン信号の
音声検波装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an audio detection device for intercarrier television signals.
従来例の構成とその問題点 ・
一般に、インターキャリア方式におけるテレビジョン信
号は映像搬送波ｆｖでＡＭ変調された映像信号と音声搬
送波でＦＭ変調された音声信号が混合されたものであり
、上記テレビジョン信号から音声信号を復調する場合に
は音声信号に映像信号が影響する関係でバスが発生し、
音質が劣化するという欠点があった。Configuration of conventional examples and their problems - In general, a television signal in the intercarrier system is a mixture of a video signal AM-modulated with a video carrier wave fv and an audio signal FM-modulated with an audio carrier wave. When demodulating an audio signal from a signal, a bus occurs due to the influence of the video signal on the audio signal.
The drawback was that the sound quality deteriorated.
発明の目的
本発明はこのような従来の欠点を解消するものであり、
バスの発生を少なくして音質の劣化を防止することがで
きる音声検波装置を提供することを目的とする。OBJECT OF THE INVENTION The present invention overcomes these conventional drawbacks.
It is an object of the present invention to provide a voice detection device capable of preventing deterioration of sound quality by reducing the occurrence of bass.
発明の構成
この目的を達成するため、本発明の音声検波装置は、映
像信号を復調した出力を利用して音声搬送波をＡＭ変調
し、このＡＭ変調された音声搬送波と、映像搬送波およ
び音声搬送波を分割する帯域フィルタで分割された映像
搬送波とを混合器で混合してビートダウンさせ、この音
声搬送波を復調するように構成したことを特長とするも
のである。Structure of the Invention In order to achieve this object, the audio detection device of the present invention performs AM modulation on an audio carrier wave using the output of demodulating a video signal, and uses this AM modulated audio carrier wave, a video carrier wave, and an audio carrier wave. This device is characterized in that it is configured such that the video carrier wave divided by the dividing band filter is mixed in a mixer and beat down, and the audio carrier wave is demodulated.
実施例の説明
第１図は本発明の一実施例を示しており、第１図におい
て、チューナ１により同調された映像搬送波及び音声搬
送波は、ＶＩＰ増幅器２により増幅される。これを通っ
た上記両搬送波は、帯域フィルタ３及び５により、映像
搬送波及び音声搬送波に分割される。この帯域フィルタ
３，５は第２図に示すような周波数−減衰特性を有して
いる。DESCRIPTION OF THE EMBODIMENT FIG. 1 shows an embodiment of the present invention, in which a video carrier wave and an audio carrier wave tuned by a tuner 1 are amplified by a VIP amplifier 2. In FIG. The two carrier waves that have passed through this are divided into a video carrier wave and an audio carrier wave by bandpass filters 3 and 5. The bandpass filters 3 and 5 have frequency-attenuation characteristics as shown in FIG.
今、帯域フィルタ３によって抽出された映像搬送波は１
Ｍ復調器４を通して第３図に示すよう々映像信号となる
。次に帯域フィルタ５によって抽出された音声搬送波は
、１Ｍ復調器４の出力を利用してＡＭ変調器６によシム
Ｍ変調された第３図に示す音声搬送波となる。このＡＭ
変調された音声搬送波と帯域フィルタ３を通した映像搬
送波を混合器７に入力させ、周波数変換を行ない、ＦＭ
復調器８で音声ＦＭ検波を行ない、音声信号を取り出す
。Now, the video carrier wave extracted by the bandpass filter 3 is 1
It passes through the M demodulator 4 and becomes a video signal as shown in FIG. Next, the audio carrier wave extracted by the bandpass filter 5 becomes the audio carrier wave shown in FIG. 3, which is subjected to shim M modulation by the AM modulator 6 using the output of the 1M demodulator 4. This AM
FM
The demodulator 8 performs audio FM detection and extracts the audio signal.
理論的には、次の様になる。すなわち、入出力特性が、
ｙ ＝ａ ｘ−１−ｂ ｘ −１−ｃ ｘ＋ ・・・・
・・・・・・・・なる１ １ １
１
ＶＩＰ回路を通ってきた時、音声及び映像搬送波は、１
式から各々２式、３式と混変調成分が加算ｘ１＝Ａｓｉ
ｎω１ｔ ・・・・・・音声搬送波ｘ２＝Ｂｓｉｎω
２ｔ ・・・・・・映像搬送波 ・１山・・（１）Ｘ
＝ｘ１＋ｘ２ とすると、混変調歪は３乗特性により
生じ、Ｘの出力として
ｘｌ ＝（ａ 、’ Ａ ２−Ｉ Ｂ Ｃ＊ Ａ ２・
Ｂ ’ ）′／２・８１ ｎ （ω１を十φ１）・・・
・・・・・・・・・（２）
φ１＝ｔａｎ ’（３０１Ｂ２／２ａ１）同様にｘ２の
出力として
ｘ二＝ （ａ：Ｂ２−１−ｚ” Ｃ，’Ａ’Ｂ２）”
ｍ ｓ ｉｎ（ω２ｔ＋φ２）・・・・・・・・・・・
・（３）
φ２＝ ｔａｎ ’ （３０１Ａ２／ ２ ａｌ）まだ
、ｘ２は、ＡＭ波であり、一般的にＡＭ式として、Ｂ
＝ Ｂｏ（１＋ｍｃｏｓ ｐｔ ） （ｍ＝変調度）と
おけば・・・・・・・・・・・・（４）
この２波により、混合器の特性を’！２”” ８２ Ｘ
十”２ ｘ ２＋ｃ２ｘ’＋ ・・・・山・・とおく
と、ｘ、９＝Ａ’５ｉｎ（ａ＋１ｔ＋φイ）、ｘ！２＝
Ｂ′５ｉｎ（ａ＋２ｔ＋φ２）１０１１１．（６）より
、ビートダウンすると（ω２−ω１）項を発生する式は
、
ｂ２ＡＢ’ｃｏｓ （（１）２−ω１ ）’ｔ＋（φ２
−φ４ ＞ −−−−−−−−・−（６）となり、こ
れをＦＭ復調する場合、位相変調項が問題となり、（φ
２−φイ）を零にしなければならない。すなわち、３式
と６式より
すなわち
ム＝Ｂｏ （１＋ｍｃｏｓｐｔ） ・・・
・・・・・ｅ−・・φ・・（８）となる必要があり、音
声搬送波も映像搬送波のＡｙ分と同じ振幅となる必要が
ある。Theoretically, it is as follows. In other words, the input/output characteristics are
y =ax-1-bx-1-cx+...
......become 1 1 1
1 When passing through the VIP circuit, the audio and video carrier waves are 1
From equations 2 and 3, respectively, and the cross modulation components are added x1=Asi
nω1t ...Audio carrier wave x2 = Bsinω
2t...Video carrier wave ・1 mountain...(1)X
=x1+x2, cross-modulation distortion occurs due to the cube characteristic, and as the output of
B')'/2・81 n (ω1 to 10φ1)...
・・・・・・・・・(2) φ1=tan' (301B2/2a1) Similarly, as the output of x2, x2= (a:B2-1-z" C, 'A'B2)"
m s in (ω2t+φ2)・・・・・・・・・・・・
・(3) φ2= tan ' (301A2/ 2 al) x2 is still an AM wave, and generally as an AM formula, B
= Bo(1+mcos pt) (m=modulation degree)...... (4) With these two waves, the characteristics of the mixer can be determined as '! 2”” 82 X
10"2
B'5in (a+2t+φ2)10111. From (6), the equation that generates the (ω2-ω1) term when beatdown is b2AB'cos ((1)2-ω1)'t+(φ2
−φ4 > −−−−−−−−・−(6), and when performing FM demodulation of this, the phase modulation term becomes a problem, and (φ
2-φa) must be made zero. That is, from equations 3 and 6, Mu=Bo (1+mcospt)...
(8) It is necessary that the audio carrier wave has the same amplitude as the Ay component of the video carrier wave.
本実施例では前述したように映像信号を復調した出力を
利用して音声搬送波を前記（８）式に合致するようにＡ
Ｍ変調された映像信号に同期させてＡＭ変調し、このＡ
Ｍ変調された音声搬送波と上記映像搬送波を混合器でミ
ックスダウンさせ、その後、７Ｍ検波するため、位相変
調項を除去することができ、この位相変調成分に起因す
るバス音をなくし、音質劣化を防止することができる。In this embodiment, as described above, the output of the demodulated video signal is used to convert the audio carrier wave to A so as to match the equation (8) above.
AM modulation is performed in synchronization with the M-modulated video signal, and this A
Since the M-modulated audio carrier wave and the video carrier wave are mixed down in a mixer and then subjected to 7M detection, it is possible to remove the phase modulation term, eliminate the bass sound caused by this phase modulation component, and reduce sound quality deterioration. It can be prevented.
発明の効果
以上のように本発明によれば、映像信号を復調した出力
を利用して音声搬送波をＡＭ変調された映像信号に同期
させてＡＭ変調し、この音声搬送波と映像搬送波とを混
合して周波数変換を行ない、ＦＭ復調器で音声ＦＭ検波
を行なうように構成したので、内部で発生する混変調に
よる位相変調分が相殺され、バズの発生が抑圧され、音
質の劣化が防止される利点を有するものである。Effects of the Invention As described above, according to the present invention, an audio carrier wave is synchronized with an AM-modulated video signal to perform AM modulation using the output of demodulating a video signal, and this audio carrier wave and video carrier wave are mixed. Since the configuration is configured such that frequency conversion is performed by the FM demodulator and audio FM detection is performed by the FM demodulator, the phase modulation due to internally generated cross modulation is canceled out, the generation of buzz is suppressed, and deterioration of sound quality is prevented. It has the following.
第１図は本発明の一実施例におけるテレビ音声検波装置
のプロ・リフ図、第２図は同装置に用いる帯域フィルタ
の特性図、第３図は同装置の映像信号波形図である。
１・・・・・・チューナ、２・山・・ｖ工Ｆ増幅器、３
，５・・・・・・帯域フィルタ、４・・・・・・ＡＭＰ
調器、６・・・・・・ＡＭ変調器、７・・・・・・混合
器、８・・団・ＦＭ復ＨＨＡＨ器。FIG. 1 is a professional diagram of a television audio detection device according to an embodiment of the present invention, FIG. 2 is a characteristic diagram of a bandpass filter used in the same device, and FIG. 3 is a video signal waveform diagram of the same device. 1... Tuner, 2. Mountain... V-engine F amplifier, 3
, 5...Band filter, 4...AMP
Modulator, 6...AM modulator, 7...Mixer, 8... Group/FM demodulator HHAH.
Claims (1)
置であって、映像搬送波および音声搬送波を分割する帯
域フィルタを具備し、映像信号を復調した出力を利用し
て音声搬送波をＡＭ変調し、このＡＭ変調された音声搬
送波と、上記帯域フィルタで分割された映像搬送波とを
混合器で混合してビートダウンさせ、この音声搬送波を
復調するように構成したことを特徴とする音声検波装置
。This is an intercarrier type audio detection device for television signals, which is equipped with a bandpass filter that separates a video carrier wave and an audio carrier wave, and performs AM modulation on the audio carrier wave using the output of demodulating the video signal. What is claimed is: 1. An audio detection device characterized in that said audio carrier wave is mixed with a video carrier wave divided by said bandpass filter in a mixer, beatdown is performed, and this audio carrier wave is demodulated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58143235A JPS5951676A (en) | 1983-08-04 | 1983-08-04 | Audio detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58143235A JPS5951676A (en) | 1983-08-04 | 1983-08-04 | Audio detection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5951676A true JPS5951676A (en) | 1984-03-26 |
| JPS6315789B2 JPS6315789B2 (en) | 1988-04-06 |
Family
ID=15334039
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58143235A Granted JPS5951676A (en) | 1983-08-04 | 1983-08-04 | Audio detection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5951676A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5198904A (en) * | 1991-02-25 | 1993-03-30 | Comark Communications, Inc. | Aural carrier correction system and method |
| US5430498A (en) * | 1994-03-01 | 1995-07-04 | Comark Communications, Inc. | Selective intermodulation correction system |
-
1983
- 1983-08-04 JP JP58143235A patent/JPS5951676A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5198904A (en) * | 1991-02-25 | 1993-03-30 | Comark Communications, Inc. | Aural carrier correction system and method |
| US5430498A (en) * | 1994-03-01 | 1995-07-04 | Comark Communications, Inc. | Selective intermodulation correction system |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6315789B2 (en) | 1988-04-06 |
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