| 摘要 |
PURPOSE:To perform remote control, by inputting a digital signal to up/down counter, inputting the output of this counter to a D/A converter and controlling a capacitance of a varactor diode with the output of the converter. CONSTITUTION:In turning on an SW1, a down pulse outputted from a gate 9 is inputted to an up/down counter 13 via a signal line 10 to decrement the count value. This count value is converted into a DC voltage lowered at a D/A converter 14 to increase the capacitance of a varactor diode 16 and to decrease the frequency of a quartz oscillator 15. In turning off the SW1 and turning on an SW2, an up-pulse outputted from a gate 9' is inputted to a counter 13 via a signal line 10' to increase the value of the counter 13. This count value is converted into a DC voltage increased at the converter 14, to decrease the capacitance of the diode 16 and to increase the frequency of the quartz oscillator 15. Since the adjustment of frequency can be done via the signal lines 10, 10', remote control can be performed. |
