- Conference Article
- 10.1109/a-sscc67472.2025.11349396
A 22Gb/s-54Gb/s Reconfigurable PAM-2/4/8 DSP-based Transmitter with 14-tap Feedforward Equalization
- Nov 02, 2025
- Seung-Mo Jin + 7 more +7
In recent high-speed serial interfaces, multi-level modulation has been widely adopted to improve bandwidth efficiency [1], [2], [3], [4]. As a result, flexibility in modulation schemes and robustness against various channel conditions have become critical requirements in transmitter (TX) design. The differences between analog based TX and digital signal processing (DSP) based TX are shown in Fig. 1. While analog-based TXs offer the advantage of low power consumption, the high-speed operation of the feedforward equalizer (FFE) imposes stringent timing constraints. Furthermore, they inherently lack flexibility in modulation schemes, and the hardware complexity increases with the number of FFE taps, as the data path size must scale accordingly [5]. As a result, analog implementations face limitations in effectively compensating for inter-symbol interference (ISI). In contrast, DSP-based TXs perform equalization through low-speed parallel processing, which significantly alleviates the timing constraints. The digital architecture also enables programmable allocation of pre- and post-cursor taps under a fixed tap budget. This provides improved configurability and adaptability over analog designs with fixed tap locations. This paper presents a DSP-based TX supporting NRZ, PAM-4, and PAM-8 modulation. A 14-tap FFE implemented within the DSP effectively compensates for ISI over channels with 17.3 dB insertion loss at the Nyquist frequency.
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