| 摘要 |
PURPOSE:To contrive to simplify operation by permitting a coefficient to be varied by a control signal while keeping a relation that one coefficient multiplying circuit multiplys by a sine when the other one multiplys by a cosine against in input signal to be processed. CONSTITUTION:When the gain of a first, a third and a fifth gain changing means, on which the same gain control voltage is impressed, is expressed by G1, and similarly, the gain of a second, a fourth and a sixth gain changing means is expressed by G2, the constant value signal of a direct current inputted to the first and the second gain changing means is expressed by P, and a reference constant value signal is expressed by PA<2>, a formula I is realized. By rewriting the formula I, the formula II is obtained, and G1 and G2 which satisfy the formula II can be expressed by the formula III and the formula IV. Accordingly the first, the third and the fifth gain changing means and the second, the fourth and the sixth gain changing means have a relation that if the gain of one side is A.cos theta, the gain of the other side is A.sin theta. In such a way, when two coefficient circuits exist, by letting the coefficient be variable by the control signal as keeping the relation that one of them multiplys the input signal by the cosine, the other one multiplys it by the sine, a troublesome operation comes to be unnecessary. |
