Patent ID: 8004342

Claim:
A mixer circuit comprising: a source of local oscillator signals connected to provide first local oscillator signals or second local oscillator signals derived from the first local oscillator signals, a first signal input port having first and second nodes, an output port having first and second nodes, switches responsive to the first local oscillator signals or the second local oscillator signals to switch between (1) connecting the first and second nodes of the first input port respectively to the first and second nodes of the output port, and (2) connecting the first and second nodes of the first input port respectively to the second and first nodes of the output port, wherein the mixer circuit further comprises a switch connected to short the first and second nodes of the first signal input port in response to a shorting signal, and a control circuit responsive to the first local oscillator signals to provide the shorting signal to short the first and second nodes of the first signal input port for periods when the switches that connect the first input port to the output port are switching.