| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication unit that can control a transmission system, so as to optimize the transmission power level of a radio wave signal in each system, when selecting the transmission system depending on a communication object. SOLUTION: A CPU 4, which is a component of a reader/writer 1, switches the transmission reception system of a transmission circuit section 17 and a reception circuit section 18 as its control to switch any of a transmission system of a radio wave signal sent to a contactless IC card 3 and of a reception system of a radio wave signal sent from the IC card 3 in plural number of systems, and controls the amplification factor of an amplifier section 10 increasingly, when the CPU 4 switches the communication system, from the communication type A with 100% of modulation level to a communication type B with 10% of modulation level. |
