Patent ID: 9742452
Date: 2017-08-22
CPC Classifications: H04B

Claim:
1. A receiver comprising: a reception unit that receives an RF signal; a local oscillator that outputs a local oscillator signal that provides an upper side heterodyne mode or a lower side heterodyne mode for the RF signal received by the reception unit; a converter that converts the RF signal received by the reception unit into an IF signal, based on the local oscillator signal output from the local oscillator; a detector that subjects the IF signal produced by conversion in the converter to detection; a first measurement unit that measures a signal intensity of the IF signal before the IF signal is input to the detector; a second measurement unit that measures a squelch voltage of a signal detected by the detector; and a controller that controls the local oscillator based on the signal intensity measured by the first measurement unit and the squelch voltage measured by the second measurement unit, wherein the controller determines that a signal is available at a frequency of the RF signal if the signal intensity in the upper side heterodyne mode and the signal intensity in the lower side heterodyne mode are both higher than a first threshold value, and if the squelch voltage is lower than a second threshold value, and determines that a signal is not available at the frequency of the RF signal if any of conditions is not met, the controller includes a scanning function to scan for a frequency of the RF signal by changing a frequency of the local oscillator signal, and the controller suspends a scan if the controller determines that a signal is available at the frequency of the RF signal and continues a scan if the controller determines that a signal is not available at the frequency of the RF signal.