Abstract:
Seen from the television receiver, the tuner is the
first stage for the electric wave received by an antenna
in selecting necessary electric waves.
As can be seen in fig. 1, the tuner is divided into
very high frequency (VHF) and ultra high frequency
(UHF), amplifying respectively received signals into
high frequency. The received signal is mixed with the
signal at the local oscillator and sent to IF amplifier
circuit.
The feature of tuner is that the input impedance of
tuner should be matched with that of the feeder
supplying signals from antenna.