| 摘要 |
The signal received by an antenna is input to a receiving circuit. The receiving circuit allows the existence of a perch channel in a particular frequency to be examined by frequency-converting the signal having the frequency corresponding to the frequency specification data within the signal received by the antenna based on the frequency specification data from a controlling circuit. A rectifying circuit rectifies the received signal, and outputs the integrated value of the signal value after being rectified. The integrated value is converted into a digital signal by an A/D converter, and compared with a threshold value by a comparing circuit. If the digital signal value is determined to be larger than the threshold value, a Write signal is output to a storing circuit, so that the frequency specification data output from the controlling circuit is stored in the storing circuit.
|
