Color killer

Color killer

The color killer is an electronic stage in color TV receiver sets which acts as a muting circuit to cut off the color amplifiers when the TV receives a monochrome signal.[1]

Contents

Monochromatic transmission

When a receiver is tuned to a monochrome transmission, the displayed scene should have no color components. However, there are two factors which result in color display even during monochrome transmission:

  • a high frequency component of the luminance signal
  • a high frequency of external noise

When the frequencies of these signals equals the frequency of the color subcarrier wave, they may create an irritating color dot pattern like confetti, which interferes with the monochrome picture.

Color transmission

In a color TV waveform, a reference pulse, called the burst[A] is transmitted along the back porch portion of the video signal. If the transmitted signal is monochromatic, then the burst is not transmitted. The color killer is actually a muting circuit in the chroma section which supervises the burst and turns off the color amplifiers if no burst is received (i.e. when the signal is received signal is monochromatic.)[2]

Equation

In NTSC and PAL transmissions, the color TV signal can be represented as: [B]

E(t) = E_y(t)+ a_1\cdot(E_b(t)-E_y(t))\cdot \sin(\omega t)+ a_2\cdot(E_r(t)-E_y(t))\cdot \cos(\omega t)

In this equation a1 and a2 are attenuation factors, Ey is the luminance signal, (EbEy) and (ErEy) are the so called color difference signals and ω is the angular frequency of the color carrier. ω is within the luminance bandwidth.[3]

References

  1. ^ [1]
  2. ^ Bernard Grob-Charles E.Herndon:Basic television and Video systems,Glanceo McGraw Hill,1998,ISBN 0-02-800437-X p 456-458
  3. ^ For more complete equation see Reference Data for Radio Engineers, Howard W.Sams Co inc,ISBN 0-672-21218-8, pp 30-14

Notes

  1. ^ Burst is actually a 10 period color carrier signal.
  2. ^ In SECAM, a similar equation can be used except that the modulation system is FM instead of QAM.

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • color killer — spalvių signalo išjungimo įtaisas statusas T sritis radioelektronika atitikmenys: angl. color killer vok. Farbsperre, f rus. устройство для выключения блока цветности, n pranc. suppresseur de couleur, m …   Radioelektronikos terminų žodynas

  • Color television — Title card for NBC, promoting their broadcast in RCA color . Color television is part of the history of television, the technology of television and practices associated with television s transmission of moving images in color video. In its most… …   Wikipedia

  • Killer Instinct — Desarrolladora(s) Rare Distribuidora(s) Midway/Rare (arcade) Nintendo (SNES, Game Boy) Diseñador(es) Chris Tilston Kevin Bayliss Mark Betteridge …   Wikipedia Español

  • Color Me Blood Red — est un film américain d horreur réalisé par Herschell Gordon Lewis, sorti en 1965. Le film est le troisième opus de la Blood Trilogy (avec Blood Feast et 2000 maniaques). Sommaire 1 Synopsis 2 Fiche technique 3 Distribution …   Wikipédia en Français

  • Killer Bunnies and the Quest for the Magic Carrot — Infobox Game subject name= Killer Bunnies and the Quest for the Magic Carrot image link= image caption= designer= Jeff Bellinger publisher= Playroom Entertainment players=2 ndash;8 ages=12+ setup time= 15 minutes playing time= 60 90 minutes… …   Wikipedia

  • Killer Nun — Infobox Film name = Killer Nun image size = caption = Original Italian poster director = Giulio Berruti producer = Enzo Gallo writer = Giulio Berruti Alberto Tarallo narrator = starring = Anita Ekberg music = Alessandro Alessandroni… …   Wikipedia

  • Killer whale — Orca redirects here. For other uses, see Orca (disambiguation). Killer whale[1] …   Wikipedia

  • Killer Queen — «Killer Queen» Sencillo de Queen del álbum Sheer Heart Attack Lado A Killer Queen» «Flick of the Wrist …   Wikipedia Español

  • Killer Instinct 2 — Infobox VG title = Killer Instinct 2 developer = Rare Ltd. publisher = Nintendo Midway (Arcade Manufacturer) designer = Chris Tilston Kevin Bayliss Mark Betteridge composer = Robin Beanland release =Arcade vgrelease|International|INT|vgy|1996… …   Wikipedia

  • TRS-80 Color Computer — 16k TRS 80 Color Computer 1 Developer Tandy Corporation Manufacturer Motorola Release date 1980 …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”