Research And Implementation Of Periodic Non-uniform Sampling Based Bandpass Signals Processing

The slow development and high price of high speed analog-digital converter vastly obstructs the progress of information acquisition. The periodic non-uniform sampling can process the bandpass analog signals which have known spectrum range but unknown actual signal spectrum position with lower average sampling frequency by digital alias-free signal processing. Therefore, it can decrease the performance requirements of the analog-digital converter in the process of sampling, save the economic cost and reduce the system losses. Moreover, less sampling points in the same sampling time can reduce the data redundancy and the complexity of the data processmg.The periodic non-uniform sampling method for the dual analog-digital converter is proposed through studying the judgment standard and the acquisition method of periodic non-uniform sampling optimal sequence. Meanwhile, the hardware implementation of the periodic non-uniform sampling based on the obtaining of optimal sequence is accomplished. The application of periodic non-uniform sampling is not widespread. This paper, through introducing the minimum energy reconstruction method of non-baseband signal, utilizes the periodic non-uniform sampling in the radar signals reconnaissance, and provides a feasible scheme of processing wideband signals of radar signal reconnaissance receiver.The implementation of the periodic non-uniform sampling method is respectively accomplished using different design schemes with the DAQ card PCI-6023E and STM32 development board using STM32F103ZET6 as MCU. Combining with LabVIEW2009 development environment, PCI-6023E DAQ card realizes the optimal sequence in a way of extracting numbers after uniform sampling. STM32 development board, taking Keil uVision4 as development environment, combining with the implementation scheme of PCI-6023E DAQ card, makes the hardware implementation of the optimal periodic non-uniform sampling sequence. STM32 takes advantage of its abundant and programmable control experimental modules such as general purpose timer, analog-digital converter, data transmission and storage. The general purpose timer generates frequency controllable trigger event, then starts the analog-digital converter and makes the process of the periodic non-uniform sampling directly. Then, the data from the two development boards is transferred to the upper computer to estimate the spectrum and being compared with the one measured in the oscilloscope so as to testify the validity of the hardware implementation of periodic non-uniform sampling. On the basis of the hardware implementation of single analog-digital converter, the periodic non-uniform sampling of the dual analog-digital converter is accomplished by using STM32 development board.The algorithm design and hardware implementation of the periodic non-uniform sampling in this paper contributes to the practical application.