Apparatus for transmitting video signal, apparatus for receiving video signal, transceiver therefor, and method for determining channel

A super heterodyne-type transceiver which modulates a video signal to be transmitted and demodulates a video signal from a received signal, the transceiver comprising:

• a duplexer filter which outputs a modulated video signal to the antenna, or receives a modulated video signal received by the antenna;
• a wide band pass filter which selects a frequency band for demodulating the modulated video signal provided by the duplexer filter;
• a demodulator which demodulates the video signal of the selected channel from a predetermined frequency band selected by the wide band pass filter;
• a modulator which modulates a video signal to be transmitted through a selected channel and provides the modulated signal to the duplexer filter;
• and
• a frequency synthesizer which sets the frequency of carriers provided to the modulator and demodulator according to the selected channel.

A channel selection method which determines a channel to be used between a transmitting apparatus that selects one of a plurality of channels and transmits a video signal, and a receiving apparatus corresponding to the transmitting apparatus, the channel selection method comprising:

• each of the transmitting apparatus and the receiving apparatus searching channels that are available;
• comparing available channels through a predetermined dedicated channel between the transmitting apparatus and the receiving apparatus, and selecting a channel to be used;
• the transmitting apparatus transmitting a pilot signal having a predetermined power through the selected channel;
• the receiving apparatus detecting the receiving power of the pilot signal, calculating an optimal transmission power needed in the transmitting apparatus, and transmitting the calculated optimal transmission power to the transmitting apparatus through the dedicated channel;
• and
• transmitting a video signal at the optimal transmission power through a channel selected by the receiving apparatus.