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• This is a transmission standard for public and commercial
broadcasting it exhibits very long life cycles. Successful market
introduction of innovations in public broadcast standards requires
major investment, including the eventual replacement of receiver
sets in all homes.
• Several enhancements have been made over time to ensure that
existing receivers in the market can continue to receive the
service. Examples of enhances made are;
• FM stereo audio, which is DSB modulated in the audio spectrum
around 38 kHz.
• AM stereo, Several systems have been proposed, but market
acceptance was low.
• RDS / HSDS data signals on FM subcarriers.
• Teletext (in blanking intervals of TV signals) has become very
popular in Europe
Digital Video Broadcasting (DVB)
• Digital Video Broadcasting is a set of standards that define digital
broadcasting using existing satellite, cable and terrestrial
• The European Launching group (ELG) formed in the early 1990s, to
discuss bringing in digital television (DTV) throughout Europe.
They later became the DVB project.
• Today the DVB project consists of 220 organisations in more than
29 countries worldwide.
Analogue FM Broadcasting
• When FM radio was introduced, it delivered an improvement in
the sound quality than AM radio.
• Despite people having the availability of different digital
alternatives, like DAB, AM, Satellite radio and HD radio, FM radio
is the main form of audio broadcasting.
• AM radio broadcasting is one of the most basic types of radio
• An AM receiver usually detects amplitude changes in the radio
waves at a specific frequency. It then amplifies a variation in the
signal voltage to drive a loud speaker.
• Teletext is a one-way, or non-interactive system for transmission
of text and graphics through broadcasting or cable to display on a
• When you punch in a page number on a teletext decoder, the
machine waits for the page to be broadcasted. The delay depends
on the number of frames that are there, it usually averages
around 5 to 30 seconds.