Shown in Figure is the front end of a 1.8-GHz receiver. The LO frequency is chosen to be 900 MHz and the load inductors and capacitances resonate with a quality factor of Q at the IF. Assume M1 is biased at a current of I1, and the mixer and the LO are perfectly symmetric.
(a) Assuming M2 and M3 switch abruptly and completely, compute the LO-IF feed through, i.e., the measured level of the 900-MHz output component in the absence of an RF signal.
(b) Explain why the flicker noise of M1 is critical here.
