| 摘要 |
PURPOSE:To eliminate dispersion of an input level to a quadrature modulator and modulation accuracy characteristics between the transmission speeds of base band I and Q signals in a modulator to which an analog band limiting filter is inserted corresponding to the transmission speed by using the plural kinds of the signals of the different transmission speeds for the base band I and Q signals. CONSTITUTION:By providing signal level adjustment circuits 34, 35, 36 and 37 in the output parts of the analog band limiting filters 5, 6, 7 and 8 corresponding to the transmission speeds, a signal level corresponding to the transmission speed is adjusted and output to DC offset circuits 11 and 12 is performed. Thus, the dispersion of the input level to the quadrature modulator between the transmission speeds of the base band I and Q signals and modulation accuracy between the transmission speeds of the base band I and Q signals is eliminated. |
