| 摘要 |
<p>When the variable frequency operation is switched on the oscillations are repeatedly counted during an accurately fixed time interval determined by a reference oscillator. A reversible counter is used. The counting result is displayed. When the locked operation is switched on, the same counter counts the oscillations backwards, starting from a reading taking into consideration the receiver or transmitter I. F. The counting is carried down to the I. F. and on reaching it the counter delivers a pulse whose phase relation is compared with the reference oscillator pulses in a phase discriminator (18). The phase discriminator delivers a control voltage for a reactance circuit, e. g. a capacitance diode of the local oscillator.</p> |
