Patent ID: 8179117

Claim:
A pulse detection device to detect a pulse signal having an intermediate potential in a predefined period, comprising a signal fixing section that fixes the intermediate potential of the pulse signal at a low level or a high level; a select switch that switches a pull-down resistor or a pull-up resistor between an On-state and an Off-state; a pulse detection section that counts a number of pulses of the pulse signal when the select switch is in the On-state; and a mask position decision section that determines a mask position for the pulse signal based on the number of pulses of the pulse signal counted by the pulse detection section, wherein the mask position decision section determines the mask position by shifting a mask cancel period having a predefined width so that the number of pulses of the pulse signal counted by the pulse detection section becomes a predefined number, and wherein the signal fixing section comprises the pull-down resistor or the pull-up resistor connected to an input signal line to which the pulse signal is input.