| 摘要 |
PURPOSE:To eliminate the ghost caused by the triple transit echo as well as to prevent deterioration of S/N for the TV picture receiver by providing the passive circuit free of loss at the front step of the elastic surface wave filter. CONSTITUTION:Coupling circuit 8 consisting of the loss-free passive elements is installed between tuner 7 and elastic surface wave filter 6. Then the input admittance of circuit 8 is set up at the termination admittance of tuner 7, and the output admittance is set to g1(1+c)/(1-c)-jb1 or (g1+g2)(1+c)/(1-c)-jb1. Here, g1 and b1 are the conductance and susceptance components of the input admittance of the elastic surface wave filter, c is the square root of the unmatching degree at the output terminal of the tuner, and g2 is the conductance of the transmission signal attenuating resistance respectively. |
