The arbitrary waveform generator is characterised by its flexible signal generation, high frequency resolution and rapid frequency switching speed and is wildly used in fields like communication, radar systems, quantum control, astronautics and biomedicine.With continuous development of technology, higher requirements are placed on to the arbitrary waveform generator. Sampling rate determines the bandwidth of the output signal, spurious-free dynamic range determines the quality of generated signal. Due to above, these two indicators’ improvement is vital. However, the existing waveform generation methods cannot generate signals with quality good enough due to their technical limitations, and in order to realize a high system sampling rate, to accomplish waveform generation process in FPGA, multipath parallel structure is needed. Therefore, we proposed a parallel waveform synthesis structure based on digital resampling, which fixed the problems existing in the current methods effectively and achieved a high sampling rate as well as high quality arbitrary waveform synthesis. We also built up an experimental test bench to validate the proposed structure.

The performance evaluation of new and old subgrades is critical for the quality and safety of reconstruction and extension projects. It is necessary to achieve rapid and easy performance testing. In this study, a Portable FallingWeight Deflectometer (PFWD) is chosen to rapid evaluate the performance of subgrade. First, a testing area, the reconstruction and expansion project of the Hefei to Dagudian section of the Shanghai-Shaanxi Expressway, is selected. Then, the PFWD modulus E_p of resilient tested by PFWD and the corresponding water content w and compacting degree K tested by the cutting ring method for old subgrade are obtained. And the correlation relationship between E_p and w and K is established. The performance of old subgrade can be rapid obtained by PFWD. Meanwhile, for the new subgrade, the correlation relationship between E_p and bending value L, w and K is established, and the performance can also be rapid tested by PFWD. Finally, a rapid evaluation method for the reconstruction and expansion of subgrade performance was proposed, which aims to provide technical support for ensuring construction quality and safety and provides a technical reference and a theoretical basis for the prediction of similar subgrade performance.