一种不用乘法器的增量调制DFT新结构
A NEW MULTIPLIER-FREE STRUCTURE FOR DFT BASED ON DELTA MODULATION
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摘要: 本文提出一种基于增量调制(DM)序列的离散傅里叶变换(DFT)结构,它不同于基于脉冲编码调制(PCM)的常规方法。提出这一想法是为了解决在常规的数字信号处理中的乘法运算问题,从而减小系统的复杂性,降低设备成本。我们将看到,本文提出的新的DFT结构取消了A/D变换器和乘法器,可望简化硬件设计、降低造价,而信噪比同样能够达到与常规的处理方法,如FFT相近的结果。计算机模拟表明,对于确定性信号,结果与常规的DFT相一致。对于带限高斯信号,只要适当地选择步长和过采样率系数,同样也能得到与常规DFT相近的结果。我们采用ROM存贮各个系数值,因此,整个运算完全是阅读和求和的过程,因而速度快,硬件结构简单,适用于语音、地震等信号的处理。本文最后给出了硬件实现方案和各个参数的选择方法,同时提供了计算机模拟结果。
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Abstract: A new implementation of the DFT based on delta modulation (DM) is proposed. It is different from the conventional implementation based on PCM. The hardware structure of the method is constructed without A/D converter and multiplier, so it is simpler and of lower cost. Its SNR can approach that of the conventional one, such as FFT. Computer simulations demonstrate that for deterministic signals, results obtained agree well with theoretical analyses, for band-limited Gaussian signals; if step size is suitably selected, results similar to the conventional DFT can still be obtained. Because of the limitation of the working speed of the device, this method will be suitable for processing speech and seismic signals. Finally, the hardware structure which simply consists of a ROM, an adder and some other auxiliary circuits is given. -
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