A semiconductor device driving unit to supply a drive signal to a gate of a semiconductor switching device, the semiconductor device driving unit comprising: a plurality of gate impedance circuits selectably connectable to the gate of the semiconductor switching device; and a selector to select one or more of the gate impedance circuits to connect to the semiconductor switching device. A method of mounting an electronic part on the mounting board is also disclosed. The transmitter includes a symbol mapper for generating a symbol for each of a plurality of subcarriers and a spreading module for spreading out the symbol on each of the plurality of subcarriers by using a direct sequence spread spectrum.