Patent ID: 7574188

Claim:
A frequency converter comprising: a first transconductance amplifier outputting first differential output current signals, corresponding to a voltage difference between radio frequency differential input voltage signals, to a pair of first output terminals; a second transconductance amplifier outputting second differential output current signals, corresponding to the voltage difference between the radio frequency differential input voltage signals, to a pair of second output terminals; a third transconductance amplifier outputting third differential output current signals, corresponding to a voltage difference between in-phase baseband differential input voltage signals, to a pair of first output terminals; a fourth transconductance amplifier outputting fourth differential output current signals, corresponding to a voltage difference between quadrature-phase baseband differential input voltage signals, to a pair of second output terminals; a first mixer down-converting the first differential output current signals in response to in-phase differential local oscillation signals and outputting down-converted first differential signals to a pair of third output terminals, and simultaneously up-converting the third differential output current signals in response to the in-phase differential local oscillation signals and outputting up-converted second differential signals to the pair of third output terminals; a first signal splitting unit splitting signals output via the pair of third output terminals into the first differential signals and the second differential signals, outputting the first differential signals via a pair of fourth output terminals, and outputting the second differential signals via a pair of fifth output terminals; a second mixer down-converting the second differential output current signals using quadrature-phase differential local oscillation signals and outputting down-converted third differential signals to a pair of sixth output terminals, and simultaneously up-converting the fourth differential output current signals using the quadrature-phase differential local oscillation signals and outputting up-converted fourth differential signals to the pair of sixth output terminals; and a second signal splitting unit splitting signals output via the pair of sixth output terminals into the third differential signals and the fourth differential signals, outputting the third differential signals via a pair of seventh output terminals, not outputting the fourth differential signals via the pair of fifth output terminals.