| 摘要 |
<p>The circuit for rapid switching over of t.v. tuner using a capacitance diode operates pref. within 0.1 to one microsecond. The tuner is switched over from one programme to another by switching the tuning voltage from one potentiometer in a set to another. An additional set of capacitance diodes (21) is provided for the other programme, to which the diode bias voltage preset on the other potentiometer is permanently applied. Both capacitance diode sets (11,21) are alternately switched for h.f. by switching diodes (12,21). The tuner has a total of eight to twelve potentiometers.</p> |
