DC-offset and 1/f noise effects on AC-coupled direct-conversion receiver

This paper analyzes the performance of a direct-conversion receiver (DCR) with ac coupling in the presence of dc-offset and 1/f noise. The performance metric employed is the SNR after the digital signal processing, as it is ultimately the most relevant measure of performance. The ac coupling, which is employed to overcome the dc-offset noise, introduces intersymbol interference (ISI), whose effects can be effectively mitigated using an equalizer. Similarly, the equalizer can also be used to mitigate the 1/f noise, which is equivalent in its effect to ISI. Our analysis shows that the performance of the ac-coupled DCR is much more sensitive to the 1/f noise compared to the ac-coupling corner frequency. This suggests that minimizing the 1/f rolloff frequency is essential for achieving high performance direct-conversion reception.