network system and signal(tv signal and video signal)

NETWORK SYSTEM AND SIGNAL

Submitted By:- Submitted To:-

Pro. Hemant MeenaKhinya Ram(2013uee1597)

CONTENT

TV SIGNAL PROPAGATION

COMPOSITE VIDEO SIGNAL

VIDEO SIGNAL FOR COLOUR


Radio waves are electromagnetic waves, which when radiated from transmitting antennas, travel through space to distant places, where they are picked up by receiving antennas

Although space is the medium through which electromagnetic waves are propagated, but depending on their wavelengths, there are three distinctive methods by which propagation takes place.



A composite video signal consists of:

Camera signal - corresponding to the desired picture information

Blanking pulses – to make the retrace invisible

Synchronizing pulses – to synchronize the transmitter and receiver scanning

horizontal sync pulse

vertical sync pulse

their amplitudes are kept same

but their duration are different

needed consecutively and not simultaneously with the picture signal – so sent on a time division basis


VIDEO SIGNAL FOR COLOURDesaturated colours• Any colour is said to be desaturated when mixed with white• In a colour camera output signal, Red colour is desaturated to a small amount, then the

Vg and Vb have lower values• But as desaturation of red increases, Vg and Vb values are increased • For 100% desaturation Vr = Vg =Vb


Colour video Frequencies:

• When the scene is not dominated by one or few colours the information to be transmitted occupies more frequency spectrum

• It is discovered that colour frequencies need 1.5 Mhz band in order to transmit finest details of a scene

• The luminance signal frequency range is up to 5 Mhz


• Colourvoltage amplitudes:

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network system and signal(tv signal and video signal)