Tone signal detector, tone signal detection method and program

摘要

PROBLEM TO BE SOLVED: To shorten the time after rising of a tone signal until opening of tone squelch, while preventing false detection of tone signal.SOLUTION: A BBPF16b passes a signal of frequency to be detected, and having a delay time shorter than a reference time, and a NBPF16n is a bandpass filter having a pass band width narrower than that of the BBPF16b. A B band detector 17b detects and outputs a wideband signal, when the intensity of a signal S16b goes above a first threshold, and an N band detector 17n detects and outputs a narrowband signal, when the intensity of a signal S16n goes above a second threshold. When the B band detector 17b detects and outputs a wideband signal, after a state where a wideband signal is not detected and outputted in the N band detector 17n, a control section 18 opens a tone squelch, and closes the tone squelch when a narrowband signal is not detected and outputted, upon elapsing a regular priority time after detection and output of the wideband signal.SELECTED DRAWING: Figure 1