JPH0720253B2 - Color difference signal switching circuit - Google Patents
Color difference signal switching circuitInfo
- Publication number
- JPH0720253B2 JPH0720253B2 JP61233544A JP23354486A JPH0720253B2 JP H0720253 B2 JPH0720253 B2 JP H0720253B2 JP 61233544 A JP61233544 A JP 61233544A JP 23354486 A JP23354486 A JP 23354486A JP H0720253 B2 JPH0720253 B2 JP H0720253B2
- Authority
- JP
- Japan
- Prior art keywords
- color difference
- difference signal
- signal
- circuit
- switching
- 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 - Lifetime
Links
Landscapes
- Processing Of Color Television Signals (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、映像色差信号に文字色差信号をデジタル領域
において埋め込む切り替え回路に関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching circuit for embedding a character color difference signal in a video color difference signal in a digital area.
従来の技術 近年、デジタル技術の発達と共に、映像信号と文字信号
の切り替えもデジタル領域で行われようとしている。以
下、図面を参照しながら、上述した切り替え回路の一例
について説明する。2. Description of the Related Art In recent years, with the development of digital technology, switching between video signals and character signals is being performed in the digital domain. Hereinafter, an example of the switching circuit described above will be described with reference to the drawings.
第３図，第４図，第５図は、従来のデジタル領域におけ
る切り替えスイッチを示すものである。第３図におい
て、３は映像色差信号を減衰させる掛算回路、４は文字
色差信号を減衰させる掛算回路、５は信号Ｊと信号Ｋを
加算する加算回路である。以上のように構成された切り
替え回路について、その動作を第４図，第５図の波形を
もとに説明する。第３図の掛算回路１は、映像色差信号
（波形Ｆ）を切り替え信号２（波形Ｇ）で減衰させる回
路でその出力信号は波形Ｊのようになる。掛算回路２
は、文字色差信号（波形Ｈ）を切り替え信号１（波形
Ｉ）で減衰させる回路であり、その出力信号は波形Ｋの
ようになる。加算回路は、掛算回路１と掛算回路２の出
力信号を加算する回路で、その出力信号は波形Ｌのよう
になり、映像色差信号（波形Ｆ）と文字色差信号（波形
Ｈ）が、切り替え信号1,2のもとに、切り替えられる。FIG. 3, FIG. 4 and FIG. 5 show conventional changeover switches in the digital domain. In FIG. 3, 3 is a multiplication circuit for attenuating the video color difference signal, 4 is a multiplication circuit for attenuating the character color difference signal, and 5 is an addition circuit for adding the signals J and K. The operation of the switching circuit configured as described above will be described based on the waveforms in FIGS. 4 and 5. The multiplication circuit 1 of FIG. 3 is a circuit for attenuating the video color difference signal (waveform F) with the switching signal 2 (waveform G), and its output signal becomes a waveform J. Multiplication circuit 2
Is a circuit for attenuating the character color difference signal (waveform H) with the switching signal 1 (waveform I), and the output signal thereof becomes like the waveform K. The adder circuit is a circuit for adding the output signals of the multiplying circuit 1 and the multiplying circuit 2, and the output signal has a waveform L, and the video color difference signal (waveform F) and the character color difference signal (waveform H) are switching signals. It can be switched under 1, 2.
発明が解決しようとする問題点 しかしながら、上記のような構成では、切り替え信号1,
2のビット数を少なくすると出力映像がジッターを起こ
すために、切り替え信号1,2のビット数が多く必要とさ
れ、それで掛算回路1,2の回路規模が、非常に大きくな
るという問題点を有していた。Problems to be Solved by the Invention However, in the above configuration, the switching signal 1,
If the number of 2 bits is reduced, the output video will cause jitter, so a large number of bits of the switching signals 1 and 2 are required, which causes a problem that the circuit scale of the multiplication circuits 1 and 2 becomes very large. Was.
本発明は、上記問題点に鑑み、デジタル領域での映像色
差信号と文字色差信号を掛算回路を用ずに切り替える切
り替え回路を提供するものである。In view of the above problems, the present invention provides a switching circuit for switching a video color difference signal and a character color difference signal in the digital area without using a multiplication circuit.
問題点を解決するための手段 上記問題点を解決するために、本発明の切り替え回路
は、映像色差信号を減衰させる減算回路とその出力信号
に文字色差信号を加算する加算回路という構成を備えた
ものである。Means for Solving the Problems In order to solve the above problems, the switching circuit of the present invention comprises a subtraction circuit for attenuating the video color difference signal and an addition circuit for adding the character color difference signal to the output signal. It is a thing.
作用 本発明は、上記した構成によって、映像色差信号を切り
替え信号をもとに、減算回路にて減衰させ、その出力信
号に文字色差信号を加算することで、映像色差信号と文
字色差信号を切り替えることとなる。Effect According to the present invention, the video color difference signal is switched between the video color difference signal and the character color difference signal by attenuating the video color difference signal in the subtraction circuit based on the switching signal and adding the character color difference signal to the output signal. It will be.
実施例 以下本発明の一実施例について図面を参照しながら説明
する。第１図は、本発明の一実施例における切り替え回
路のブロック図を示すものである。第１図において、１
は映像色差信号を減衰させる減算回路、２はその出力信
号に文字色差信号を加算させる加算回路である。Embodiment One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a switching circuit according to an embodiment of the present invention. In FIG. 1, 1
Is a subtracting circuit for attenuating the video color difference signal, and 2 is an adding circuit for adding the character color difference signal to the output signal.
以上のように構成された切り替え回路について、以下第
１図，第２図及び第６図を用いてその動作を説明する。The operation of the switching circuit configured as described above will be described below with reference to FIGS. 1, 2, and 6.
まず、第２図のＡに示されるような、映像色差信号及
び、Ｂに示されるような、切り替え信号が第１図の１の
減算回路に加えられる。この減算回路は、第６図のよう
に加算器、EXOR,AND,NOR,で構成され、信号Ａのような
入力されたデジタル信号（第６図においては、信号Ａは
反転二進としている）の最上位ビットで、その符号を識
別し、その符号が正であるならば、信号Ｂの切り替え信
号をEXORを用いて反転し、キャリーと共に信号Ａに加算
することで減算回路として働かせその後、その減算され
た結果の最上位ビットで負の数とならないように、リミ
ッタをかけている。また信号Ａが負であるならば、その
まま信号Ｂの切り替え信号を加算し、その結果が正の数
とならないように、リミッタをかけている。その結果と
して信号Ｄのようになる。次にその信号Ｄに、文字色差
信号である信号Ｃを第１図の２の加算回路で加算し、信
号Ｅとなり、映像色差信号と文字色差信号が切替えられ
た。First, a video color difference signal as shown in A of FIG. 2 and a switching signal as shown in B are added to the subtraction circuit 1 in FIG. This subtraction circuit is composed of an adder, EXOR, AND, NOR, as shown in FIG. 6, and an input digital signal such as signal A (in FIG. 6, signal A is an inverted binary signal). The sign is identified by the most significant bit of, and if the sign is positive, the switching signal of the signal B is inverted using EXOR and added to the signal A together with carry to act as a subtraction circuit, and then the A limiter is applied so that the most significant bit of the subtracted result does not become a negative number. If the signal A is negative, the switching signal of the signal B is added as it is, and a limiter is applied so that the result does not become a positive number. As a result, signal D is obtained. Next, the signal C, which is a character color difference signal, is added to the signal D by the adder circuit 2 in FIG.
以上のように本実施例によれば、従来の掛算回路のよう
な大規模の回路を用いずに、減算回路と加算回路で、映
像色差信号と文字色差信号を切り替えることができる。As described above, according to the present embodiment, the subtraction circuit and the addition circuit can switch the video color difference signal and the character color difference signal without using a large-scale circuit such as a conventional multiplication circuit.
発明の効果 以上のように、本発明は、減算回路，加算回路により映
像色差信号と文字色差信号を切り替えることができ、デ
ジタル領域においての映像色差信号と文字色差信号の切
り替えの実用化に効果大なるものがある。Effects of the Invention As described above, the present invention can switch the video color difference signal and the character color difference signal by the subtraction circuit and the addition circuit, and is highly effective in the practical application of switching the video color difference signal and the character color difference signal in the digital area. There is something.
第１図は本発明の一実施例における色差信号切り替え回
路のブロック図、第２図はその信号波形図、第６図は同
要部の回路図、第３図は従来例の色差信号切り替え回路
の回路図、第４図，第５図はその信号波形図である。 １……減算回路、２……加算回路、Ａ……映像色差信
号、Ｂ……切り替え信号、Ｃ……文字色差信号。FIG. 1 is a block diagram of a color difference signal switching circuit according to an embodiment of the present invention, FIG. 2 is a signal waveform diagram thereof, FIG. 6 is a circuit diagram of its main part, and FIG. 3 is a color difference signal switching circuit of a conventional example. 4 and 5 are signal waveform diagrams thereof. 1 ... Subtraction circuit, 2 ... Addition circuit, A ... Video color difference signal, B ... Switching signal, C ... Character color difference signal.
Claims (2)
号から切り替え信号を加算又は減算を行いその結果の符
号が前記映像色差信号の符号と異なるときリミッタをか
けゼロにする減算回路と、前記減算回路の出力に文字色
差信号を加算する加算回路を備えたことを特徴とする色
差信号切り替え回路。1. A subtraction circuit for adding or subtracting a switching signal from the video color difference signal according to the code of the video color difference signal and applying a limiter to zero when the resulting code is different from the code of the video color difference signal; and the subtraction. A color difference signal switching circuit comprising an addition circuit for adding a character color difference signal to the output of the circuit.
切り替え信号がｎ−１ビットのデジタル信号である特許
請求の範囲第１項記載の色差信号切り替え回路。2. A video color difference signal and a character color difference signal are n bits,
The color difference signal switching circuit according to claim 1, wherein the switching signal is an n-1 bit digital signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61233544A JPH0720253B2 (en) | 1986-10-01 | 1986-10-01 | Color difference signal switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61233544A JPH0720253B2 (en) | 1986-10-01 | 1986-10-01 | Color difference signal switching circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6387893A JPS6387893A (en) | 1988-04-19 |
| JPH0720253B2 true JPH0720253B2 (en) | 1995-03-06 |
Family
ID=16956719
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61233544A Expired - Lifetime JPH0720253B2 (en) | 1986-10-01 | 1986-10-01 | Color difference signal switching circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0720253B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3002247B2 (en) * | 1990-09-25 | 2000-01-24 | シャープ株式会社 | Character superimposition device |
| AU640578B2 (en) * | 1991-12-06 | 1993-08-26 | Agricultural Genetics Company Limited | Method of preparing va mycorrhizae inoculant |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58159082A (en) * | 1982-03-16 | 1983-09-21 | Sharp Corp | Superposing device of character and pattern signals |
-
1986
- 1986-10-01 JP JP61233544A patent/JPH0720253B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6387893A (en) | 1988-04-19 |
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