| 摘要 |
PURPOSE:To detect surely a desired wave by constituting the titled detector that a capcitor whose charging is controlled by a white noise and a VCO is swept by the charge/discharge signal of the said capacitor. CONSTITUTION:The desired wave entering from an antenna 1 is converted into an IF signal by the 1st and 2nd mixers 2, 5 and demodulated by a detector 7. When no signal input exists, a switch 11 is turned on/off by the white noise and the capacitor 13 is charged. The charging voltage of the capacitor is discharged at a prescribed period by a switch 14 controlled by a pulse generator 15. A sawtooth voltage based on the charging/discharging is used as a sweep voltage of the VCO16. When the signal is received as the result of sweep, the switch 11 is turned off. As a result the sweep of the VCO is stopped, the detector 7 generates a wide pulse output to drive an alarm device 10. |
