Steps in Digital Channel Transmission (Simplified)

Procurement / Production of material

This is in the form of Videotapes containing the source material, as it is prepared by outside producers or in-house. This may be serials or advertisements.

Capsuling

The process of putting together the source material onto the final broadcast tapes in the sequence that it is to be broadcast. Some other final touches may be applied to the material (like the channel logo) at this stage. The tape is then ready for transmission.

Digitizing, Compression, Multiplexing

The tapes are played back into the Analog to digital converters. This process obtains digital signals that can be compressed using MPEG algorithms and then multiplexed with each other. Multiplexing is a way of mixing two or more signals in a way so that the original signals can be completely recovered.

Transmitting

The multiplexed signal is then fed into the uplink equipment and is transmitted to the satellite. The satellite receives the signal and returns it exactly as is.
Reception

The returned signal is received using dishes and is fed into the specially built multi-channel reception equipment that can re-convert the digital signal into a viewable analog signal in the following manner:

Demultiplexing / Digital to Analog conversion

At the first stage the signal is demultiplexed, i.e. separated into its various constituent channels. These are then converted from their digital to their analog form so that they can be seen on ordinary TV Sets.

Note: Though the concept of tapeless broadcast is attractive the equipment still remains expensive and out of reach for many broadcast companies.