Development Of Pseudo-random Sequence Generator For Sub-nyquist System Based On Modulated Wideband Converter

Modulated wideband converter is a sub-Nyquist sampling method based on compressed sensing. The hardware implementation of MWC requires a mixing signal, and the transition frequency of mixing signal should be at least the Nyquist rate of the test signal. Then, when the frequency of test signal reaches a GHz level, the design of mixing signal generator becomes a problem to MWC physical implementation. Pseudo-random sequence is frequently used as a mixing signal, so this paper focuses on the pseudo-random sequence generator of MWC system, the main research contents are as follows:1. Research on the principle of MWC technology and the overall scheme of PRSG. The compressed sensing theory and MWC principles are introduced at first, then carries on a detailed theoretical analysis in frequency domain, on this basis analyzes the importance of mixing signal in MWC and how hard to design a mixing signal generator. Then on the basis of design indices of a MWC system, proposes the main design specifications and implementation scheme of a pseudo-random mixing signal generator. This PRSG is designed by FPGA with high speed clock circuits and parallel/serial converter circuits.2.Design a PRSG and build a hardware experiment platform. PRSG contains four same channels on hardware construction, and consists of the following main parts: FPGA control module, parallel/serial converter module, high speed clock module, power module and RS232 communication module. The hardware design process of PRSG is divided into three steps: schematic design, PCB design and firmware design. All steps are important for the hardware implementation.3. The design and simulation of signal integrity. The proposed design of a PRSG needs a data transition speed of 2Gbps, which belongs to high speed signal design, and the transmission of these frequency band signals will easily run into reflection, crosstalk and other signal integrity problems, some simulations are carried out to avoid these problems.4. Conduct experiments by using of this PRSG system. Debugs and analyzes the designed pseudo-random sequence generator. The results show that the pseudo-random sequence waveform produced by the designed generator is consistent with the simulation conclusion, and the transition rate can reach up to 2Gbps, with same frequency intervals, satisfies the request of MWC system.