tailieunhanh - Fourier Transforms in Radar and Signal Processing_1

Bằng cách xây dựng dựa trên Woodward nổi tiếng của "Quy tắc và cặp" phương pháp và các khái niệm liên quan và thủ tục, văn bản thiết lập một hệ thống thống nhất làm cho tiềm ẩn sự tích hợp cần thiết để thực hiện Fourier biến đổi trên một loạt các chức năng. Nó chi tiết các chức năng phức tạp có thể được chia nhỏ cho các bộ phận cấu thành của họ để phân tích. Cách tiếp cận này để áp dụng biến đổi Fourier được minh họa bằng nhiều ví dụ cụ thể từ xử. | Introduction 9 spond to the samples that would have been obtained by sampling the waveform with the time offset. The ability to do this when the waveform is no longer available is important as it provides a sampled form of the delayed waveform. If the waveform is sampled at the minimum rate to retain all the waveform information accurate interpolation requires combining a substantial number of input samples for each output value. It is shown that oversampling sampling at a higher rate than actually necessary can reduce this number very considerably to quite a low value. The user can compare the disadvantage if any of sampling slightly faster with the saving on the amount of computation needed for the interpolation. One example from a simulation of a radar moving target indication MTI system is given where the reduction in computation can be very great indeed. The problem of compensating for spectral distortion is considered in Chapter 6. Compensation for delay a phase error that is linear with frequency is achieved by a technique similar to interpolation but amplitude compensation is interesting in that it requires a new set of transform pairs including functions derived by differentiation of the sinc function. The compensation is seen to be very effective for the problems chosen and again oversampling can greatly reduce the complexity of the implementation. The problem of equalizing the response of a wideband antenna array used for a radar application is used as an illustration giving some impressive results. Finally in Chapter 7 we take advantage of the fact that there is a Fourier transform relationship between the illumination of a linear aperture and its beam pattern. In fact rather than a continuous aperture we concentrate on the regular linear array which is a sampled aperture and mathematically has a correspondence with the sampled waveforms considered in earlier chapters. Two forms of the problem are considered the low side-lobe directional beam and a much