Elimination of image blocking problem for single tuner IDTV applications

In this thesis, a specific dijital image blocking problem was solved for the single tuner IDTV application. A single hybrid tuner is used and the IF (intermediate frequency) output signals of the tuner are divided by two, as analog side (LCD-TV main board) IF input signals and digital side (digital module card) IF input signals. The digital module card is used for IF demodulating and MPEG (moving pictures expert group standard) decoding. The analog IF demodulating process is made in LCD TV main board. The hybrid tuner is located on that main board. The IF output of the tuner is carried to the digital module card by a cable. To distribute the IF output of the hybrid tuner to analog side and digital side and to use an IF cable for carrying the IF signal to the digital module card, impair the IF signal shape. In this thesis, the image blocking problem was solved. The source of the problem was found as impedance mismatching and IF signal impairing. The new high frequency emitter follower circuits were designed for solving this problem.