Topic2-DSP.ppt

1、Technical English，for information science and electronic engineering，unit 9，electronic s 3360 Digital signals and signal process signal processing for communication s，biomedical sigs音频和语音信号处理，声纳和雷达信号处理，传感器阵列处理，频谱估计，统计信号处理，图像处理，通信信号处理，生物医学信号处理，7，2，sis 8 The algorithms required for DSP are some times

2、performed using specialized computers，which make use of specialized micro processors called dadthese process signals in real to And are generally purpose-designed application-specific integrated circuits(ASIC). 1，这些(数字信号处理器engineers usually study digital signals in one of the following domains 3360

3、time domain(one-domain)Spatial domain(multi dimein) ，11，4，a sequence of samples from a measuring device produces a time or spatial domain re presentation，Whereas a discrete Fourier transfrancessampling is usually carried out In two stages，discretization and quantion采样通常包括两个阶段：离散化和量化，13，5，In the disc

4、retization stage。the space of signals is partitioned into equivalence classes and discretization is carried out by replacing the signal with re presentative signal ool，用有限的集中值近似代表性信号值。14，6，in order for a sampled analog signal to be exactly reconstructed，The Nyquist-Shannon sampling theorem must be s

5、atisfied . this15，6，in practice，the sampling frequency is often significantly more than twice the requirer And fcbw，a frequency band centered on a取样频率通常是信号带宽的两倍，远远大于16，7。digital to analog converter(DAC)Is used to convert the digital signal back to analog . the use of a digital computer Is a key ingr

6、edient into do，17、8小时和空间域，The most common processing approach in The time or space domain is enhancement of The input signal through a method called filting18，8，a linear filter is a linear transformation of input samples；other filters are“non-linear”linear filters satisfy The super position conditio

7、n，i.e .If an input is a weighted linear condition也就是说，如果输入是其他信号的加权线性组合，则输出(分别为，19，8，a causal filter uses only previous samples of the input or output signals；while a non-causal filter uses future input samples . a non-causal filter can usually be changed into a causal filter by addid E-iiiother filt

8、ers such as adaptive filters change in time。”时间不变”过滤器是其他过滤器，如随时间变化的可变过滤器，20，8，some filters are“some Others are”“unstable”。A stable filter produces an output that converges to A constant value with time，Or remains bounded within A finite interval . an unstable filter pilter无限脉冲响应(IIR)过滤器同时使用输入信号和先前的输出信号样本，22，9。most filters can