Radio having a fast adapting direct conversion receiver

摘要

A direct conversion receiver (200) is capable of recovering a filtered baseband signal (295) from a radio signal (201) modulated with a baseband signal (202). The direct conversion receiver (200) comprises a radio frequency mixer (205) for converting the radio signal (201) to the baseband signal (202), a lowpass amplifier (210) DC coupled to the radio frequency mixer (205), that amplifies the baseband signal (202) and substantially attenuates components of the baseband signal above a high corner frequency, and a DC offset compensation section (225) DC coupled to the lowpass amplifier (210), that provides a DC offset compensation and a controlled highpass filtering of the baseband signal. A low corner frequency of the DC offset compensation section is smoothly varied from a predetermined maximum value to a predetermined minimum value during a low frequency, low energy portion of the signaling protocol.