| 摘要 |
PROBLEM TO BE SOLVED: To make a portable radio terminal, etc., small in size and light in weight by enabling a transmitting multiplication circuit and a receiving multiplication circuit to be used in common by, utilizing a voltage-current conversion integrated circuit to execute the addition of a transmitting low-frequency signal and a receiving high-frequency signal. SOLUTION: A frequency converter 32 is the frequency conversion circuit of sharing use for transmission and reception, and is connected to the band pass filter 15 and the variable attenuator 17 of a transmitting part 10B and the band pass filters 22, 24 of a receiving part 20B, and receives the control of a switching control circuit 31, and executes the multiplication of a local oscillation signal from a local oscillator 7 and each input signal. The frequency converter 33 is the frequency conversion circuit of combination use for transmission and reception for 1ch, and the frequency converter 34 is the frequency conversion circuit of combination use for transmission and reception for Qch respectively, and they execute the multiplication of the oscillation signal of a second local oscillator 8 or its 90 deg.-phase-shifted signal and each input signal. Thus, the transmitting and the receiving frequency conversion circuits having existed independently are used in common, and an IC is highly integrated, and the miniaturization and the low power consumption of the portable radio terminal is attained. |
