| 摘要 |
<p>RCA 71,007 PHASE LOCKED LOOP TUNING SYSTEM WITH A PRESET CHANNEL MEMORY A divide-by-N programmable counter arrangement of a phase locked loop tuning system is programmed by selectively coupling one of a group of preset tuning potentiometers corresponding to respective tuning positions to a monostable multivibrator. The monostable multivibrator determines the duration of a counting interval and thereby controls the frequency of a local oscillator signal generated by the phase locked loop tuning system. The count accumulated during the counting interval is stored and displayed during another interval to indicate the selected tuning position.</p> |
