Nonlinear distortion compensation for high-speed ADC using a diffusion model

To address the amplitude/phase distortion and intermodulation distortion caused by nonlinearity of the sampling switch and front-end amplifier, clock jitter, and frequency coupling in high-speed ADCs (Analog to Digital Converters), this paper proposes a conditional Diffusion framework based on physical constraints for nonlinear distortion compensation in high-speed ADCs. The study uses a one-dimensional time series Temporal-UNet as the denoising backbone and fuses the calibrated hardware parameter vector with jitter spectrum estimation through a conditional encoder. FiLM is used to inject conditional information into the residual block to guide progressive inverse diffusion. Then, in each step of the inverse process, a data consistency projection based on a memory polynomial physical forward model is embedded. The Gauss-Newton approximation solution is used, combined with STFT (Short Time Fourier Transform)-L1 and spectral convergence term to constrain the network output to suppress intermodulation and phase distortion. Finally, in the deployment link, low-latency engineering implementation is achieved through methods such as few-step deterministic sampling, progressive distillation, model pruning, and quantization. Parallel multi-sample uncertainty estimation and lightweight online fine-tuning ensure domain adaptability and reliability. A comprehensive evaluation based on a hybrid simulation and experimental dataset — comprising single-tone sweep, two-tone intermodulation, multi-tone, and modulation signal scenarios over an input frequency range of 10 MHz to 450 MHz and a normalized input amplitude range of 0.1 to 1.0 full scale, with an uncompensated baseline ENOB of 4.37 bits at full-scale high-frequency input — shows that the proposed method achieves suppression of THD (Total Harmonic Distortion) and IMD (Intermodulation Distortion) of approximately 73.04% and 78.15% respectively in the high-frequency band above 300 MHz. The ENOB (Effective Number of Bits) increased by 3.21 ± 0.16 bits, the SNDR (Signal-to-Noise and Distortion Ratio) increased by 11.07 ± 0.76 dB, and the SFDR (Spurious Free Dynamic Range) increased by 9.57 ± 0.99 dB. Experimental results demonstrate that this method can achieve high-fidelity signal reconstruction in different frequency bands and under complex operating conditions, providing a reliable technical solution for accurate measurement and communication link optimization in high-speed ADC systems.