Patent ID: 8140044

Claim:
A mixer circuit to mix a RF (Radio Frequency) signal with a LO (Local Oscillator) signal to generate an IF (Intermediate Frequency) signal, the mixer having a mixing branch comprising: a first transconductance stage having an RF input to receive the RF signal to transform into a current signal; a first current switching core to switch the current signal according to the LO signal and an LO signal which forms with the LO signal a differential signal; a dummy branch connected in parallel of the mixing branch, the dummy branch comprising: a second transconductance stage having an input connected to a reference potential which is independent from the RF signal, to transform the reference potential into a current signal; and a second current switching core to switch the current signal according to LO and LO signals; and chopping switches to connect in series the transconductance stages of the mixing branch to the first current switching core and, in the alternative, to the second current switching core under the control of a chopping signal, wherein the mixer circuit further comprises a chopping signal generator able to generate the chopping signal which is a pseudo-random bit sequence that systematically includes as many logical zeros as logical ones over one period, and wherein the pseudo-random bit sequence generator comprises: a pseudo-random bit sequence builder which builds a pseudo-random bit sequence having a period T B and having a number of logical zeros different from the number of logical ones over period T B ; and a reversing core able to alternatively output the built pseudo-random bit sequence and its opposite so as to output a longer pseudo-random bits sequence having as many logical zeros as logical ones over each period of this longer pseudo-random bit sequence.