JPS6138313Y2 - - Google Patents
Info
- Publication number
- JPS6138313Y2 JPS6138313Y2 JP2177481U JP2177481U JPS6138313Y2 JP S6138313 Y2 JPS6138313 Y2 JP S6138313Y2 JP 2177481 U JP2177481 U JP 2177481U JP 2177481 U JP2177481 U JP 2177481U JP S6138313 Y2 JPS6138313 Y2 JP S6138313Y2
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- tuner
- signal
- teletext
- voltage
- 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
- 239000000284 extract Substances 0.000 claims description 2
- 238000001514 detection method Methods 0.000 description 5
- 230000010355 oscillation Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Landscapes
- Television Systems (AREA)
- Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)
Description
【考案の詳細な説明】
本考案は、文字多重放送受信時に正確に文字多
重信号を再生することができるようにする受信機
を提供するもので、使用者が受信周波数を容易に
正確に同調させるように調整できるように表示す
るものである。[Detailed description of the invention] The present invention provides a receiver that can accurately reproduce a teletext signal when receiving teletext broadcasting, and allows the user to easily and accurately tune the receiving frequency. It is displayed so that it can be adjusted accordingly.
文字多重放送は従来のテレビジヨン放送信号の
映像と音声信号以外の文字情報を多重化して伝送
するものである。具体的には、テレビジヨン信号
の垂直帰線期間内の水平走査期間に符号化等した
文字多重信号を重畳し、受信機側ではこの文字多
重信号を取り出して再生し、CRT上に文字情報
を再生するものである。既に、英国では実用化放
送が行われており我国でも実験放送が行われてい
る。 Teletext multiplexing is a method of multiplexing and transmitting text information other than the video and audio signals of conventional television broadcast signals. Specifically, an encoded character multiplex signal is superimposed on the horizontal scanning period within the vertical retrace period of the television signal, and the receiver side extracts and reproduces this character multiplex signal to display character information on the CRT. It is something to be regenerated. Practical broadcasting is already underway in the UK, and experimental broadcasting is also underway in Japan.
文字多重放送は２値信号化された文字多重信号
から文字信号を再生するものであるため、受信機
ではチユーナの同調周波数が正規の周波数より約
50KHz以上ずれていると再生信号が歪み、誤つた
信号が再生されるという問題がある。通常の受信
機ではチユーナの局部発振周波数のずれを検出し
て自動的に正規の周波数に同調させる自動周波数
制御回路（以下AFC回路と称する）が設けられ
てはいるが、AFC回路が動作している場合でも
局部発振周波数のずれは100〜150KHz程度存在す
る。通常のテレビ放送を受信している場合にはこ
のような100〜150KHzのずれであれば映像と音声
の再生において実用上特に問題はないが、文字多
重放送受信の場合には上記のように不都合を生じ
る。この場合、使用者が局部発振周波数を微調整
して±50KHz以内に同調すればよいが、画面を見
ながら調整しても正確に調整することはきわめて
困難である。 Since teletext broadcasting reproduces character signals from a binary teletext signal, the tuning frequency of the tuner in the receiver is approximately higher than the regular frequency.
If the difference is more than 50KHz, there is a problem that the reproduced signal will be distorted and the wrong signal will be reproduced. Normal receivers are equipped with an automatic frequency control circuit (hereinafter referred to as the AFC circuit) that detects deviations in the tuner's local oscillation frequency and automatically tunes to the correct frequency, but the AFC circuit is not activated. Even when there is a difference in local oscillation frequency of about 100 to 150 KHz. When receiving regular TV broadcasts, a deviation of 100 to 150 KHz does not cause any practical problems in the reproduction of video and audio, but when receiving teletext broadcasts, it is inconvenient as described above. occurs. In this case, the user can fine-tune the local oscillation frequency to within ±50 KHz, but it is extremely difficult to make accurate adjustments even if the user makes adjustments while looking at the screen.
そこで、本考案は容易にチユーナの発振周波数
を正規の周波数に正確に調整可能な装置を提供す
ることを目的とするものである。 Therefore, an object of the present invention is to provide a device that can easily and accurately adjust the oscillation frequency of a tuner to a regular frequency.
以下、本考案につき、図面を参照して説明す
る。まず、第１図に本受信機のブロツク図を示
す。図において、１はアンテナ、２はチユーナ、
３は映像中間周波増幅及び検波回路、４は色信号
再生回路、５は映像信号増幅回路、６は文字信号
再生回路、７は陰極線管である。また、８，９は
AFC電圧検出用の電圧比較機、１０，１１はそ
の検出用の基準電圧を発生する定電圧素子、１２
は表示用の発光ダイオードである。 The present invention will be described below with reference to the drawings. First, FIG. 1 shows a block diagram of this receiver. In the figure, 1 is an antenna, 2 is a tuner,
3 is a video intermediate frequency amplification and detection circuit, 4 is a color signal reproducing circuit, 5 is a video signal amplifying circuit, 6 is a character signal reproducing circuit, and 7 is a cathode ray tube. Also, 8 and 9 are
A voltage comparator for AFC voltage detection; 10 and 11 are constant voltage elements that generate a reference voltage for detection; 12
is a light emitting diode for display.
かかる構成において、VIF・映像検波回路３よ
り第２図に示すように同調周波数のずれに応じた
AFC電圧Vfが出力され、チユーナ２に印加さ
れ、正規の同調周波数に引き込むように制御され
る。このAFC電圧Vfは周波数のずれにほぼ比例
しており、たとえば、ある機種においてはこの
AFC電圧が４〜8V程度の範囲内であれば50KHz
以内に同調されている状態となる。そこで、定電
圧素子１０，１１を4Vと8Vとして、電圧比較器
８，９でAFC電圧と比較し、その出力は共通の
負荷抵抗１３で結合されて、AFC電圧、VfがVz1
〜Vz2の間にあれば出力端子は高レベルとなり、
発光ダイオード１２が点灯し、50KHz以内に同調
されたことを示す。従つて、同調周波数を調整し
て１２が点灯するところに合わせれば、正確に同
調させることができ、容易に調整できる。 In this configuration, the VIF/video detection circuit 3 detects
The AFC voltage Vf is output and applied to the tuner 2, and is controlled so as to draw it into the regular tuning frequency. This AFC voltage Vf is almost proportional to the frequency shift, and for example, in some models, this
50KHz if the AFC voltage is within the range of 4 to 8V
It will be in a state where it is synchronized within the range. Therefore, the constant voltage elements 10 and 11 are set to 4V and 8V, and the voltage comparators 8 and 9 compare the AFC voltage with the AFC voltage .
~Vz 2 , the output terminal will be at high level,
The light emitting diode 12 lights up, indicating that it is tuned within 50KHz. Therefore, by adjusting the tuning frequency to match the point where 12 lights up, accurate tuning can be achieved and adjustment can be made easily.
このように、本考案によれば文字多重放送を誤
りなく受信することができるように、発光ダイオ
ード等による表示を見ながら同調周波数を容易に
正確に調整できるものである。 As described above, according to the present invention, the tuning frequency can be easily and accurately adjusted while viewing the display by a light emitting diode or the like so that teletext can be received without error.
第１図は本考案の一実施例における文字多重放
送受信機のブロツク図、第２図はその動作を説明
する特性図である。
２……チユーナ、３……VIF・検波回路、６…
…文字信号再生回路、８，９……電圧比較器、１
０，１１……定電圧素子、１２……発光ダイオー
ド。
FIG. 1 is a block diagram of a teletext receiver according to an embodiment of the present invention, and FIG. 2 is a characteristic diagram illustrating its operation. 2...Tuner, 3...VIF/detection circuit, 6...
... Character signal reproduction circuit, 8, 9 ... Voltage comparator, 1
0, 11... constant voltage element, 12... light emitting diode.
Claims (1)
いる文字多重信号を取り出して再生する受信機に
おいて、そのチユーナに加えられる自動周波数制
御電圧の大きさを検出し、文字多重信号を正確に
受信しうる範囲内に同調周波数が調整されている
か否かを表示するようにしたことを特徴とする文
字多重放送受信機。 In a receiver that receives television broadcast signals, extracts and reproduces the multiplexed text multiplex signal, it is possible to detect the magnitude of the automatic frequency control voltage applied to the tuner and accurately receive the text multiplex signal. A teletext broadcasting receiver characterized by displaying whether or not a tuning frequency is adjusted within a range.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2177481U JPS6138313Y2 (en) | 1981-02-17 | 1981-02-17 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2177481U JPS6138313Y2 (en) | 1981-02-17 | 1981-02-17 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57135174U JPS57135174U (en) | 1982-08-23 |
| JPS6138313Y2 true JPS6138313Y2 (en) | 1986-11-05 |
Family
ID=29819618
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2177481U Expired JPS6138313Y2 (en) | 1981-02-17 | 1981-02-17 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6138313Y2 (en) |
-
1981
- 1981-02-17 JP JP2177481U patent/JPS6138313Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57135174U (en) | 1982-08-23 |
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