| 摘要 |
PURPOSE:To make the reception frequency variable with a simple constitution, by controlling a programable counter of a PLL receiver according to the rotating direction and amount of revolution of a channel selection knob. CONSTITUTION:When a rotating shaft l of a channel selection knob 1 is rotated clockwise, a sliding electrode provided on this rotating shaft moves from left to right in Figure on conductor patterns 3, 3', and a time difference is producted at the time point when switch circuit S, S' transit from off to on-state. Thus, in a transit signal generating circuit B, the time difference is produced to the transit signals S1, S1' produced only when the switches S, S' transit from off to on-state. Thus, since the transit signals S1, S1' are inputted to a control signal generating circuit C about that time, a transist signal C2 is produced only under the absence of the transit signal S1' and no control signal is produced at an output section O'. The programable counter of a PLL receiver is up-counted with this signal C2 and the reception frequency is increased. |
