Abstract: In high-efficiency simultaneous-source acquisition systems, severe wavefield interference due to overlapping shot records significantly degrades imaging quality. This paper focuses on optimizing multi-source encoding strategies and proposes an encoding design principle governed by dual constraints in the time and frequency domains. In the time domain, shot-to-shot dithering delays follow a uniform distribution, subject to constraints of non-repeatability, absolute threshold, and standard deviation threshold. In the frequency domain, based on the principle that blending noise should be mapped into high-wavenumber regions, the trend of power spectral density is adopted as the criterion for evaluating encoding performance. Deblending experiments conducted on both synthetic and field datasets demonstrate that the proposed encoding scheme effectively reduces aliasing between the signal and blending noise, thereby improving separation quality. Furthermore, this design principle exhibits strong adaptability across different sparse inversion methods, confirming that its effectiveness is not limited to any specific separation algorithm.