摘要 |
When a demodulated signal of a radio signal in Ch1 transmitted from a TPMS transmitter is acquired, a control IC controls the frequency of a signal inputted from a PLL circuit to a mixer into a frequency for converting a TPMS radio signal into an intermediate frequency signal of a specific frequency. When the demodulated signal of the radio signal transmitted from a portable unit through two frequency channels is acquired, the control IC determines a channel whose state of communication is favorable from between Ch2 and Ch3, and controls the signal frequency for conversion into a frequency for converting a keyless radio signal in the determined channel into an intermediate frequency signal. |