A Distributed Waveform Generation and Digitization System Based on Transparent Transmission

Abstract: Waveform generation and digitization play essential roles in numerous physics experiments. In traditional distributed systems for large-scale experiments, each front-end node contains an FPGA for data pre-processing, which interfaces with various of data converters and exchanges data with a back-end central processor. However, streaming readout architecture has become the new paradigm for many experiments, benifits from the advance- ments in data transmission and computing technologies. This paper proposes a scalable distributed waveform generation and digitization system that utilizes fiber optical connections for data transmission between front-end nodes and the central processor. By utilizing transparent transmission on top of the data link layer, the clock and data ports of the converters in front-end nodes are directly mapped to the FPGA firmware in the back-end. This streaming readout architecture reduces the complexity of front-end development and keeps the data conversion close to the detector. Each front-end node uses a local clock for waveform digitization. To translate the tim- ing information of events in each channel into the system clock domain within the back-end central processing FPGA, a novel method is proposed and evaluated using the demonstrator system.