Offset compensation in a direct-conversion receiver

A baseband processing assembly capable of compensating received and demodulated analog differential signals in at least one channel of a direct conversion receiver for DC offset, wherein, for each of the at least one channel, said baseband processing assembly comprises:

• a baseband amplifier capable of amplifying the demodulated differential signals;
• a variable-gain amplifier capable of receiving and further amplifying the amplified demodulated differential signals from said baseband amplifier;
• a pair of dynamic offset compensation elements each comprising a capacitor, wherein one dynamic offset compensation element is electrically connected to said baseband amplifier and the other dynamic offset compensation element is electrically connected to said variable-gain amplifier;
• and
• a static offset compensation element electrically connected to said variable-gain amplifier opposite said baseband amplifier, wherein said static offset compensation element comprises:
• an analog-to-digital converter electrically connected to an output of said variable-gain amplifier opposite said baseband amplifier, wherein the direct conversion receiver is capable of operating in an initialization mode where the direct conversion receiver operates independent of communication signals and the analog-to-digital converter is capable measuring an amount of offset at the output of said variable-gain amplifier and thereafter generating a digital differential control code based upon the measured amount of offset;
• and
• a digital-to-analog converter capable of receiving the digital differential control code and thereafter converting the digital differential control code into an analog differential control code,
• wherein said static offset compensation element is capable of compensating at least a portion of static offset from the further amplified demodulated differential signals based upon a combination of the analog differential control code with the further amplified demodulated differential signals from the variable-gain amplifier.

A direct conversion receiver comprising:

• a low noise amplifier capable of receiving communication signals from an antenna;
• a bandpass filter capable of filtering the received signals to within a reception frequency band;
• a mixer circuit electrically connected to an output of said bandpass filter capable of demodulating the received signals into differential signals in two channels;
• and
• a baseband processing assembly electrically connected to said mixer circuit opposite said bandpass filter, for each channel said baseband processing assembly comprising:
• a baseband amplifier;
• a variable-gain amplifier electrically connected to said baseband amplifier opposite said mixer circuit;
• a pair of dynamic offset compensation elements each comprising a capacitor, wherein one dynamic offset compensation element is electrically connected to said baseband amplifier and the other dynamic offset compensation element is electrically connected to said variable-gain amplifier;
• and
• a static offset compensation element electrically connected to said variable-gain amplifier opposite said baseband amplifier, wherein said static offset compensation element is capable of receiving a differential control code representative of static offset and thereafter combining the differential control code with output differential signals from the variable-gain amplifier.