Baseband harmonic rejection circuit

An apparatus in a receiver for baseband harmonic rejection, the apparatus comprising:

• a plurality of frequency conversion cells configured to mix an input signal with a plurality of non-overlapping local oscillator (LO) signals to produce down-converted signals;
• and
• a plurality of transimpedance amplifiers coupled to the plurality of frequency conversion cells and configured to produce output voltage signals proportional to respective ones of the down-converted signals, wherein each of the plurality of transimpedance amplifiers comprises:
• a plurality of transconductance cells coupled to one another at outputs of the plurality of transconductance cells and each configured to receive respective ones of the down-converted signals to produce a weighted current signal proportional to a voltage corresponding to the down-converted signal,
• wherein each of plurality of transconductance cells has an effective transconductance of a first magnitude for frequency components of the input signal arising from a first harmonic and an effective transconductance of a second magnitude less than the first magnitude for frequency components of the input signal arising from harmonics at integer multiples of the first harmonic.

An apparatus for baseband amplification with harmonic rejection, the apparatus comprising:

• means for receiving a mixed signal down-converted from a radio frequency signal;
• means for converting the mixed signal into a weighted current signal proportional to a voltage corresponding to the mixed signal based on an effective transconductance;
• and
• means for outputting the mixed signal with amplification using a feedback impedance such that a wanted signal receives the amplification and unwanted signals are rejected without amplification,
• wherein the effective transconductance has a first magnitude for frequency components of the down-converted signal arising from a first harmonic and the effective transconductance has a second magnitude less than the first magnitude for frequency components of the down-converted signal arising from harmonics at integer multiples of the first harmonic.