| 摘要 |
PROBLEM TO BE SOLVED: To easily execute ramp processing by controlling the on/off of an analog signal outputted from a D/A converter through a switch corresponding to a transmission on/off control signal when a modulation system, with which an envelope becomes zero in the middle of transmission, is used. SOLUTION: This device is provided with a mapping circuit 1 for mapping transmission signals onto signal point arrangement, D/A converter 2 and 3 for converting the signals of Ich and Qch provided by mapping to analog signals, switches 4 and 5, and band limit filters 6 and 7 for limiting the bands of analog signals after on/off control. Then, when the modulation system, with which the envelope becomes zero in the middle of transmission, is used, the on/off of analog signals from the D/A converters 2 and 3 is controlled through the switches 4 and 5 corresponding to the transmission on/off control signal. Thus, since the fluctuation of the envelope in the middle of transmission gets remarkable more than just after transmission start, by suppressing adjacent channel leak power during transmission, any special ramp processing is not required. |
