Wideband Digital Receiver Algorithm And Simulation Research

With the constant improvement of radar performance requirements of modern warfare and the more mature of digital processing technology, digital array radar has become the mainstream in the development of radar. Wideband digital receiver because of its broadband, large dynamic range, parallel signal processing, wideband signal real-time processing ability, became an important part of current digital array radar. Radio technology effectively solved the former ubiquitous digital receiver problems, such as the low precision, high power consumption. Digital intermediate frequency receiver based on software radio can not only save development cost, and has higher flexibility and generality, so the system can complete the upgrade improvement with the minimum cost. Now to the platform, the main factors restricting the development of digital receiver is the speed of high-speed analog-to-digital converter(ADC) and subsequent digital signal processor.In the wideband digital receiver, ADC is a very important device, received RF analog signals are converted to digital signals by ADC. As a turning point of analog to digital, ADC plays an important role in the signal processing of receiver. The maximum sampling rate of the ADC limits the maximum processing bandwidth of receiver, and the resolution of ADC also affects the dynamic range of receiver. The high-speed ADC dynamic range in general can’t satisfy the requirement of receiver for large bandwidth, large dynamic range, so we need to use multiple parallel sampling ADC, so as to realize the real-time signal processing. Multi-channel digital IF processing scheme is used generally at present, broadband analog signal from the multi channel into the receiver, this scheme with much lower rates of ADCs, signal is modulated to baseband in the digital domain, then restore the broadband signal, which not only can guarantee high sampling rate but also can guarantee high precision.This paper based on the multi-channel digital receiver, first introduced the software radio theory relates to adigital receiver, proposed wideband multichannel receiver scheme, especially studied of the receiver-channel technology, introduced channels and wideband synthetic technology, and designed and simulated in single channel as an example。Then, the multi-channel receiver equalization algorithm is introduced, mainly introduced the frequency domain algorithm and channel equalization technology based on Fourier transform. In order to optimize the fitting effect, the basic frequency domain algorithm is modified, used the weighted least squares fitting method and discussed some factors effect the performance of the algorithm in detail.Finally, this paper tudied the problem of receiver’s ADC clock jitter, theoretically analyzed the effect of sampling clock jitter on signal, according to the analysis of sine signal, baseband signal of linear frequency modulation and frequency chirp signal, derived the clock jitter on ADC output signal-to-noise ratio effect formula, and gave the method of using ADC for measuring jitter, finally through the simulation experiment verified the correctness of the theory and feasibility.