Patent ID: 9020078
Filing Date: 2015-04-28
Classification: H04B

Abstract:
1. A signal detection device, comprising: a band limiting filter with a cutoff frequency which is changeable; a signal detection unit that detects whether or not a signal of a specific frequency is present, from a received signal; and a control unit that executes a first signal detection that causes said signal detection unit to detect the signal, when a first cutoff frequency of said band limiting filter is less than a Nyquist frequency of an A/D (Analog/Digital) converter, and a second signal detection that causes said signal detection unit to detect the signal, when a second cutoff frequency of said band limiting filter is greater than or equal to the Nyquist frequency of said A/D converter; wherein, initially, the cutoff frequency of said band limiting filter is set to first cutoff frequency of less than the Nyquist frequency of said A/D converter to perform signal detection and in a case where it is determined that no signal is present in a band below the first cutoff frequency, the cutoff frequency of said band limiting filter is set to the second cutoff frequency of greater than or equal to the Nyquist frequency of said A/D converter.