Advancing Baud Rate Receivers: On Multiple CTLE Parameters Background Adaptation

The continuous-time linear equalizer (CTLE) is a key component in receivers for improving the achievable bit error rate. Available CTLE background adaptation methods are limited to adjusting a single parameter, such as the source resistance or capacitance. In contrast, this paper presents a background adaptation method capable of concurrently finding near-optimal source resistance and capacitance values for multiple CTLE configurations in baud rate communication. Moreover, this paper presents a sequential method for adjusting both short and long-tail CTLE parameters, ensuring effective system control. The multiple loop interactions are considered with recent DSP-based receivers main building blocks, such as the clock and data recovery (CDR) and automatic gain control (AGC). A relatively simple logic based on inter-symbol interference (ISI) taps is employed, similar to conventional Mueller-Muller methods, which does not impose significant hardware overhead compared to previous publications. Simulations using real channel models demonstrate the proposed adaptation’s performance across a wide range of insertion loss channels and various modulations.