JPH07143511A - Secam chrominance signal demodulator - Google Patents
Secam chrominance signal demodulatorInfo
- Publication number
- JPH07143511A JPH07143511A JP28824993A JP28824993A JPH07143511A JP H07143511 A JPH07143511 A JP H07143511A JP 28824993 A JP28824993 A JP 28824993A JP 28824993 A JP28824993 A JP 28824993A JP H07143511 A JPH07143511 A JP H07143511A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- output
- average value
- vco
- lpf
- 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
Landscapes
- Processing Of Color Television Signals (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ＳＥＣＡＭ方式のＴＶ
信号のクロマ（色）信号を復調するＳＥＣＡＭ色信号復
調器に関するもので、特に調整箇所を削減し、ＩＣ化に
適したＳＥＣＡＭ色信号復調器に関する。BACKGROUND OF THE INVENTION The present invention relates to a SECAM type TV.
The present invention relates to a SECAM color signal demodulator that demodulates a chroma (color) signal of a signal, and particularly to a SECAM color signal demodulator that reduces adjustment points and is suitable for IC implementation.
【０００２】[0002]
【従来の技術】ＳＥＣＡＭ色信号は、Ｂ−Ｙ信号とＲ−
Ｙ信号とが線順次で送られており、そのキャリア周波数
も４．２５ＭＨｚ（Ｂ−Ｙ）と４．４０６ＭＨｚ（Ｒ−
Ｙ）とで異なっている。そこで、従来は、ＰＬＬ型検波
器のＶＣＯの中心周波数を４．３３ＭＨｚ（４．２５Ｍ
Ｈｚと４．４０６ＭＨｚのキャリアの中間値）に手動で
調整し、色信号の検波を行なっていた。2. Description of the Related Art SECAM color signals are BY signals and R- signals.
The Y signal is sent line-sequentially, and the carrier frequencies thereof are 4.25 MHz (B-Y) and 4.406 MHz (R-
It is different from Y). Therefore, conventionally, the center frequency of the VCO of the PLL type detector is 4.33 MHz (4.25 M).
It was manually adjusted to the intermediate value between the carrier of Hz and the carrier of 4.406 MHz, and the color signal was detected.
【０００３】図２は、その様なＳＥＣＡＭ色信号復調器
に関するもので、ベルフィルタ（１）により抽出された
ＳＥＣＡＭ色信号は、リミッタアンプ（２）で振幅制限
された後、ＰＬＬ検波器（３）に印加される。位相比較
器（４）は、リミッタアンプ（２）の出力信号とＶＣＯ
（５）の出力信号との掛算を行ない、掛算結果は、不要
成分が第１ＬＰＦ（６）で除去された後、ＶＣＯ（５）
に帰還される。その為、ＶＣＯ（５）は、到来するＳＥ
ＣＡＭ色信号の位相に周期する。又、ＶＣＯ（５）の中
心周波数は、４．３３ＭＨｚになるように可変抵抗
（７）が調整されＶＣＯ（５）に加わる直流制御電圧が
変化する。FIG. 2 relates to such a SECAM color signal demodulator. The SECAM color signal extracted by the bell filter (1) is amplitude-limited by a limiter amplifier (2) and then a PLL detector (3 ) Is applied. The phase comparator (4) outputs the output signal of the limiter amplifier (2) and the VCO.
Multiplication with the output signal of (5) is performed, and the multiplication result is VCO (5) after the unnecessary components are removed by the first LPF (6).
Be returned to. Therefore, VCO (5) is the SE
It cycles to the phase of the CAM color signal. The variable resistor (7) is adjusted so that the center frequency of the VCO (5) is 4.33 MHz, and the DC control voltage applied to the VCO (5) changes.
【０００４】この為、第１ＬＰＦ（６）の出力端にはＰ
ＬＬ検波されたＳＥＣＡＭ色信号が現われ、第２ＬＰＦ
（８）で更に不要成分が除去されて出力端子（９）に導
出される。Therefore, the output terminal of the first LPF (6) has P
The LL detected SECAM color signal appears and the second LPF
At (8), the unnecessary component is further removed and is led to the output terminal (9).
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、図２の
方法では手動で調整しなければならず、可変抵抗（７）
を必要とする、という問題があった。However, the method of FIG. 2 requires manual adjustment, which results in a variable resistor (7).
There was a problem that I needed.
【０００６】[0006]
【課題を解決するための手段】本発明は上述の点に鑑み
成されたもので、ＳＥＣＡＭ色信号とＶＣＯの発振出力
信号とを位相比較する位相比較器と、該位相比較器の出
力信号中から不要成分を除去するＬＰＦと、該ＬＰＦの
出力信号中からＲ−Ｙ信号とＢ−Ｙ信号のＩＤ信号を検
出し、その平均値を検出する平均値検出手段と、該平均
値検出手段の出力信号と前記ＬＰＦの出力信号とを加算
し、その加算出力により前記ＶＣＯの発振周波数を制御
する加算器と、を有することを特徴とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and a phase comparator for phase-comparing a SECAM color signal and an oscillation output signal of a VCO, and an output signal of the phase comparator Of the LPF that removes unnecessary components from the output signal, the average value detection means that detects the ID signal of the RY signal and the BY signal from the output signal of the LPF, and detects the average value, and the average value detection means. And an adder that adds the output signal and the output signal of the LPF and controls the oscillation frequency of the VCO by the added output.
【０００７】[0007]
【作用】本発明に依れば、ＰＬＬ検波されたＳＥＣＡＭ
信号中のＲ−Ｙ信号とＢ−Ｙ信号のＩＤ（識別信号であ
り、Ｂ−Ｙ信号時は、４．２５ＭＨｚ、Ｒ−Ｙ信号時は
４．４０６ＭＨｚの信号のことであり、所謂バースト信
号の一種）信号を検出し、その平均値を得、該平均値に
基づいてＶＣＯの発振周波数を調整している。According to the present invention, PLL-detected SECAM
IDs of the RY signal and the BY signal in the signal (identification signal, which is a signal of 4.25 MHz for the BY signal and 4.406 MHz for the RY signal, a so-called burst signal Signal is detected, an average value thereof is obtained, and the oscillation frequency of the VCO is adjusted based on the average value.
【０００８】[0008]
【実施例】図１は、本発明の一実施例を示す回路図で、
（１０）はＳＥＣＡＭ色信号とＶＣＯの発振出力信号と
を位相比較する位相比較器、（１１）は該位相比較器の
出力信号中から不要成分を除去するＬＰＦ、（１２）は
該ＬＰＦの出力信号中からＲ−Ｙ信号とＢ−Ｙ信号のＩ
Ｄ信号を検出し、その平均値を検出する平均値検出手
段、（１３）は該平均値検出手段の出力信号と前記ＬＰ
Ｆの出力信号とを加算し、その加算出力により前記ＶＣ
Ｏの発振周波数を制御する加算器である。FIG. 1 is a circuit diagram showing an embodiment of the present invention.
(10) is a phase comparator that compares the phase of the SECAM color signal and the oscillation output signal of the VCO, (11) is an LPF that removes unnecessary components from the output signal of the phase comparator, and (12) is the output of the LPF. I of the RY and BY signals from the signals
An average value detecting means for detecting the D signal and detecting the average value thereof, (13) is an output signal of the average value detecting means and the LP.
The output signal of F is added, and the VC
It is an adder that controls the oscillation frequency of O.
【０００９】ＬＰＦ（１１）から発生する復調された色
信号の波形は、図３の如くなる。図３に示すようにＢ−
Ｙ信号のＩＤ信号は、４．２５ＭＨｚのキャリアが復調
されたレベルを有しており、Ｒ−Ｙ信号のＩＤ信号は、
４．４０６ＭＨｚのキャリアが復調されたレベルを有し
ている。その為、この２つのレベルの平均値は、前述の
４．３３ＭＨｚのキャリアをレベル復調したものに相当
する。そこで、本発明では、前記平均値を平均値検出手
段（１２）により検出し、その検出出力をＶＣＯ（５）
に印加しているので、ＶＣＯ（５）の中心周波数を４．
３３ＭＨｚに自動調整できる。The demodulated color signal waveform generated from the LPF (11) is as shown in FIG. As shown in FIG.
The ID signal of the Y signal has a level obtained by demodulating the carrier of 4.25 MHz, and the ID signal of the RY signal is
The 4.406 MHz carrier has the demodulated level. Therefore, the average value of these two levels corresponds to the level-demodulated carrier of 4.33 MHz described above. Therefore, in the present invention, the average value is detected by the average value detecting means (12), and the detection output is detected by the VCO (5).
, The center frequency of VCO (5) is set to 4.
It can be automatically adjusted to 33 MHz.
【００１０】即ち、ＬＰＦ（１１）の出力信号は、平均
値検出手段（１２）の差動アンプ（１４）に印加され
る。差動アンプ（１４）は、動作電流源（１５）がスイ
ッチ（１６）で導通及び遮断することにより、動作・不
動作状態となる。そこで、図３（ｂ）の如き、ＢＧＰ
（バーストゲートパルス）の「Ｈ」レベルによりスイッ
チ（１６）を閉じれば、ＩＤ信号のレベルを検出でき
る。差動アンプ（１４）は、電流出力型でありコンデン
サ（１７）を充放電制御するので、コンデンサ（１７）
にはＩＤ信号の平均直流電圧が得られる。該平均直流電
圧は、バッファ（１８）を介して加算器（１３）に印加
され、ＬＰＦ（１１）の出力信号と加算されＶＣＯ
（５）に印加される。That is, the output signal of the LPF (11) is applied to the differential amplifier (14) of the average value detecting means (12). The differential amplifier (14) is in an operating / non-operating state when the operating current source (15) is turned on and off by the switch (16). Therefore, as shown in FIG.
The level of the ID signal can be detected by closing the switch (16) according to the "H" level of (burst gate pulse). Since the differential amplifier (14) is of the current output type and controls the charging and discharging of the capacitor (17), the capacitor (17)
, The average DC voltage of the ID signal is obtained. The average DC voltage is applied to the adder (13) via the buffer (18), added to the output signal of the LPF (11), and added to the VCO.
It is applied to (5).
【００１１】従って、ＶＣＯ（５）は、中心周波数が
４．３３ＭＨｚに自動調整された上で、到来する色信号
の周波数及び位相に同期する。Therefore, the VCO (5) is automatically adjusted to have a center frequency of 4.33 MHz and then synchronized with the frequency and phase of the incoming color signal.
【００１２】[0012]
【発明の効果】以上述べた如く、本発明によればＳＥＣ
ＡＭ色信号を検波するＰＬＬ検波器内のＶＣＯの中心周
波数を自動調整することができる。その為、調整用の部
品やその作業が不要になる、という利点を有する。As described above, according to the present invention, the SEC
The center frequency of the VCO in the PLL detector that detects the AM color signal can be automatically adjusted. Therefore, there is an advantage that parts for adjustment and its work are not required.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明のＳＥＣＡＭ色信号復調器を示すブロッ
ク図である。FIG. 1 is a block diagram showing a SECAM color signal demodulator of the present invention.
【図２】従来のＳＥＣＡＭ色信号復調器を示すブロック
図である。FIG. 2 is a block diagram showing a conventional SECAM color signal demodulator.
【図３】図１の説明に供する為の波形図である。FIG. 3 is a waveform chart for explaining FIG.
５ ＶＣＯ １０ 位相比較器 １２ 平均値検出方法 １３ 加算器 5 VCO 10 Phase comparator 12 Average value detection method 13 Adder
Claims (2)
号とを位相比較する位相比較器と、 該位相比較器の出力信号中から不要成分を除去するＬＰ
Ｆと、 該ＬＰＦの出力信号中からＲ−Ｙ信号とＢ−Ｙ信号のＩ
Ｄ信号を検出し、その平均値を検出する平均値検出手段
と、 該平均値検出手段の出力信号と前記ＬＰＦの出力信号と
を加算し、その加算出力により前記ＶＣＯの発振周波数
を制御する加算器と、 を有することを特徴とするＳＥＣＡＭ色信号復調器。1. A phase comparator for phase-comparing a SECAM color signal and a VCO oscillation output signal, and an LP for removing unnecessary components from the output signal of the phase comparator.
F and I of the RY signal and the BY signal from the output signals of the LPF.
An average value detecting means for detecting the D signal and detecting the average value thereof, an addition signal for adding the output signal of the average value detecting means and the output signal of the LPF, and controlling the oscillation frequency of the VCO by the addition output. A SECAM chrominance signal demodulator, comprising:
到来を示すＢＧＰに応じて動作する電流出力型の差動ア
ンプと、該差動アンプの出力電流により充放電されるコ
ンデンサとを有することを特徴とする請求項１記載のＳ
ＥＣＡＭ色信号復調器。2. The average value detecting means includes a current output type differential amplifier that operates in accordance with BGP indicating the arrival of the ID signal, and a capacitor that is charged and discharged by the output current of the differential amplifier. S according to claim 1, characterized in that
ECAM color signal demodulator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05288249A JP3123865B2 (en) | 1993-11-17 | 1993-11-17 | SECAM color signal demodulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05288249A JP3123865B2 (en) | 1993-11-17 | 1993-11-17 | SECAM color signal demodulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07143511A true JPH07143511A (en) | 1995-06-02 |
| JP3123865B2 JP3123865B2 (en) | 2001-01-15 |
Family
ID=17727766
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05288249A Expired - Fee Related JP3123865B2 (en) | 1993-11-17 | 1993-11-17 | SECAM color signal demodulator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3123865B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0952740A1 (en) * | 1998-04-24 | 1999-10-27 | STMicroelectronics S.A. | Demodulator, in particular of SECAM chrominance signal, with double frequency tuning |
-
1993
- 1993-11-17 JP JP05288249A patent/JP3123865B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0952740A1 (en) * | 1998-04-24 | 1999-10-27 | STMicroelectronics S.A. | Demodulator, in particular of SECAM chrominance signal, with double frequency tuning |
| FR2778052A1 (en) * | 1998-04-24 | 1999-10-29 | Sgs Thomson Microelectronics | DEMODULATOR, IN PARTICULAR OF SECAM CHROMINANCE SIGNAL, WITH DOUBLE FREQUENCY ADJUSTMENT |
| US6433837B1 (en) | 1998-04-24 | 2002-08-13 | Stmicroelectronics | Demodulator, particularly for a SECAM chrominance signal, with double frequency adjustment |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3123865B2 (en) | 2001-01-15 |
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