In modern communication and radar systems, the real-time processing of high-speed ADC sampling data serves as a core technical challenge. With the rapid development of 5G communication, phased array radar, satellite communication and other applications, the sampling rate of ADCs has exceeded 1 GSps, and the number of channels has increased to 96 or even higher. How to realize real-time processing under such high data throughput has become a major bottleneck in system design.

1. Challenges of High-Speed ADC and Real-Time Processing

Modern high-speed ADCs (such as ADI AD9208 and TI ADC12DJ5200) have achieved a single-channel sampling rate of 3 GSps or higher. Taking a 96-channel system with a 1.2 GHz sampling rate per channel as an example, the total system data throughput exceeds 200 Gbps, placing extremely high requirements on data transmission, storage and real-time processing capabilities.

The main challenges are summarized as follows. First is massive data throughput pressure. Although the JESD204B/C interface supports high-bandwidth serial transmission, FPGA internal wiring and timing convergence remain critical difficulties. Second is stringent real-time requirements. Applications including radar pulse detection and 5G beamforming require signal processing to be completed within microseconds. Third is multi-channel synchronization. A 96-channel system requires sub-nanosecond phase consistency, which imposes ultra-high standards for clock distribution and calibration algorithms.

2. Real-Time Processing System Architecture

The typical real-time processing system architecture follows the flow: High-speed ADC → JESD204C Interface → FPGA (integrated with DDC, FIR, FFT and other DSP modules) → DDR4 Mass Storage Cache → PCIe/NVMe High-Speed Transmission. GPU or ASIC accelerators are also introduced in certain scenarios for subsequent advanced processing.

As the mainstream high-speed ADC interface standard, JESD204C supports a single-channel bandwidth of up to 24 Gbps, and achieves a total bandwidth of over 100 Gbps through multi-channel binding. Inside the FPGA, physical coding sublayer (PCS) and physical medium attachment (PMA) modules complete high-speed serial deserialization, and distribute data to each independent processing channel.

3. Analysis of Core Key Technologies

Multi-Channel Synchronous Sampling: Phase consistency is the core of multi-channel system design. We adopt a cascaded clock distribution architecture. The main clock is distributed to all ADCs and FPGAs through low-jitter clock chips (such as LMK04828). Combined with the JESD204C SYNC synchronization mechanism, sub-nanosecond-level synchronization of all channels is realized stably.

Real-Time Digital Down Conversion (DDC): DDC is a key module for converting broadband intermediate frequency signals to baseband signals. We implement configurable DDC modules inside FPGAs, supporting 16-channel parallel processing. Each channel is equipped with an independently adjustable local oscillator (32-bit NCO), with a configurable decimation factor ranging from 2 to 256 and an output bit width of 16 to 32 bits, meeting diverse signal processing requirements.

Breakthroughs in Storage and Transmission Bottlenecks: Data storage is a major bottleneck of real-time processing. We adopt a hierarchical storage architecture combining DDR4 and NVMe SSD. DDR4 provides microsecond-level high-speed cache, while NVMe delivers a continuous writing speed of several GB/s. Cooperated with DMA engine and scatter-gather technology, zero-copy data transmission is realized, minimizing overall storage delay.

4. Typical Application Scenarios

5G Base Station Massive MIMO Testing: Modern 5G base stations support 64T64R or even 128T128R antenna configurations, requiring test equipment with matching channel scale. Our 96-channel tester can simultaneously capture IQ data from all antenna ports and calculate key indicators such as EVM and ACLR in real time.

Phased Array Radar Signal Simulation: Phased array radar requires multi-channel coherent reception and real-time beamforming processing. Our platform supports multi-channel phase calibration and real-time beam scanning. Cooperated with DDC and FFT processing pipelines, it completes pulse detection and parameter estimation during signal acquisition.

High-Speed Serial Protocol Analysis: High-speed serial protocols such as PCIe 5.0 and CXL 2.0 have a data rate exceeding 32 Gbps, which cannot be covered by traditional logic analyzers. Our solution directly samples physical layer signals through 1.6 GHz high-speed ADCs, and realizes real-time protocol decoding and error detection inside FPGAs.

5. Xtelli High-Speed Integrated Digital Tester Solution

Based on the above technical accumulation, Beijing Xtelli Technology has launched a new-generation 96-channel 1.6 GHz high-speed integrated digital tester. The product supports fully synchronous output of 96 channels with a maximum differential frequency of 1.6 GHz per channel. It is also equipped with 34 digital input channels with a sampling rate up to 1.6 GSps.

The product adopts Xilinx FPGA as the core processing unit, built-in 96-channel DDC modules, multi-channel FFT acceleration engine and high-precision real-time trigger system. Equipped with rich external interfaces, including 1.6 GHz SMA analog input/output, 1.2 GHz digital I/O, 10GbE data interface and USB 3.0 control interface. The software supports MATLAB/Simulink co-simulation, and provides C++/Python API for user secondary development.

6. Future Development Trends

High-speed ADC real-time processing technology is still evolving rapidly. Firstly, the integration of ADC and processing units based on Chiplet technology integrates ADC, SerDes and DSP into a single package, greatly reducing interconnection delay and power consumption. Secondly, the integration of AI accelerators and real-time processing embeds NPU units into FPGAs to realize intelligent processing such as signal classification and anomaly detection. Thirdly, the practical application of photonic ADCs breaks electronic bottlenecks through optical sampling, achieving a sampling rate above 10 GHz.

Beijing Xtelli Technology will continue to invest in the research and development of high-speed signal processing and FPGA prototype verification technologies, providing customers with more powerful, reliable and user-friendly test and measurement solutions.