Pixel : it is the smallest unit of picture that can be represented or controlled. Prof.Bhavin Gajjar/Indus University

Requirement of the scanning Prof.Bhavin Gajjar/Indus University

Vidicon camera tube Prof.Bhavin Gajjar/Indus University

Primary colour : Light reflacted from any colour picture element can be synthesised into Red, Green and Blue colour light. This forms the basic of colour TV are called Primary colour. Complementary colour : It is formed by mixing any two of the primaries. Luminance(Y): Light reflected from any colour element of a picture also carries information about its brightness called Luminance. Y = V R + V G + V B (30:59:11) Prof.Bhavin Gajjar/Indus University

Monochrome Television Transmitter Prof.Bhavin Gajjar/Indus University

Monochrome Television Receiver Prof.Bhavin Gajjar/Indus University

Number of scanning lines Prof.Bhavin Gajjar/Indus University

Interlaced scanning Prof.Bhavin Gajjar/Indus University

Interlace Error It occurs due to time difference in starting the scanning of the second field at the exact mid point of the top. Error = {[(32us + Delay) – 32]/32 } * 100 Why the number of lines are odd ? Prof.Bhavin Gajjar/Indus University

The ability of the image reproducing system to represent the fine structure of an object is known as its resolving power or resolution. Vertical resolution. The extent to which the scanning system is capable of resolving picture details in the vertical direction is referred to as its vertical resolution. Horizontal resolution. The capability of the system to resolve maximum number of picture elements along the scanning lines determines horizontal resolution. Prof.Bhavin Gajjar/Indus University

Any colour has three characteristics to specify its visual information. (i) Luminance or Brightness This is the amount of light intensity as perceived by the eye regardless of the colour. In black and white pictures, better lighted parts have more luminance than the dark areas. Different colours also have shades of luminance in the sense that though equally illuminated appear more or less bright.Thus on a monochrome TV screen, dark red colour will appear as black, yellow as white and a light blue colour as grey. (ii) Hue This is the predominant spectral colour of the received light. Thus the colour of any object is distinguished by its hue or tint. The green leaves have green hue and red tomatoes have red hue. Different hues result from different wavelengths of spectral radiation and are perceived as such by the sets of cones in the retina. (iii) Saturation This is the spectral purity of the colour light. Since single hue colours occur rarely alone, this indicates the amounts of other colours present. Thus saturation may be taken as an indication of how little the colour is diluted by white. A fully saturated colour has no white. As an example. vivid green is fully saturated and when diluted by white it becomes light green. The hue and saturation of a colour put together is known as chrominance. Note that it does not contain the brightness information. Chrominance is also called chroma. Prof.Bhavin Gajjar/Indus University

Vertical Sync Details Prof.Bhavin Gajjar/Indus University

Equalizing Pulses Prof.Bhavin Gajjar/Indus University

Function of Equalizing Pulses Vertical slots of 4.7us duration that are inserted in the vertical sync period to achieve horizontal synchronization are called serrated pulses.  Triggering to the vertical oscillator  HO receives triggering pulses even during the vertical blanking due to the presence of serrated pulses  Vertical sync pulses are available at the end of the line of second field and at the middle of the line at the end of first field.  The equalizing pulses are provided to avoid timing error at VO.  The shape of the vertical trigger pulse is maintained at both even and odd fields. Prof.Bhavin Gajjar/Indus University

Sync Seperator Prof.Bhavin Gajjar/Indus University

Grass man’s Law Prof.Bhavin Gajjar/Indus University

Colour TV Camera Prof.Bhavin Gajjar/Indus University

SaturationDesaturation Saturation : It is the indication of how little the colour is diluted by white. 100% Saturation means pure colour (Heu) Desaturation: Colour is said to be desaturated when white is mixed with it. 100% desaturation means white. Prof.Bhavin Gajjar/Indus University

Colour video frequencies Compatibility Problem Solution Colour-Difference Signals R – Y G – Y B – Y Compatibility with colour-difference signals  For R=G=B  R– Y=0 and B—Y=0 ∆ only Y signal  Colour-Difference singnal are smaller than Y and RGB  Colour-Difference doesn’t need large BW as for Y signal Prof.Bhavin Gajjar/Indus University

Chrominance Signal generation Prof.Bhavin Gajjar/Indus University

Colour Burst Prof.Bhavin Gajjar/Indus University

Frequency Interleaving  It has been determined that the energy content of the video signal is contained in individual energy ‘bundles’ which occur at harmonics of the line frequency (15.625, KHz) the components of each bundle being separated by a multiplier of the field frequency (50, 100,... Hz).  The carrier frequency is so chosen that its sideband frequencies fall exactly mid-way between the harmonics of the line frequency. Prof.Bhavin Gajjar/Indus University