ROM size of the present design is still very large. Hence a 7th order with 8 coefficients having 28=256 look up table values is implemented. Coefficients designed by the ‘fdatool’ of the MATLAB are:, , , , , , and . | Chapter 7 Fundamentals of Digital Signal Processing Digital signal processing DSP is based on the fact that an analog signal can be digitized and input to a general-purpose digital computer or specialpurpose digital processor. Once this is accomplished we are free to perform all sorts of mathematical operations on the sequence of digital data samples inside the processor. Some of these operations are simply digital versions of classical analog techniques while others have no counterpart in analog circuit devices or processing methods. This chapter covers digitization and introduces the various types of processing that can be performed on the sequence of digital values once they are inside the processor. Digitization Digitization is the process of converting an analog signal such as a timevarying voltage or current into a sequence of digital values. Digitization actually involves two distinct parts sampling and quantization which are usually analyzed separately for the sake of convenience hnd simplicity. Three basic types of sampling shown in Fig. are ideal instantaneous and natural. From the illustration we can see that the sampling process converts a signal that is defined over a continuous time interval into a signal that has nonzero amplitude values only at discrete instants of time as in ideal sampling or over a number of discretely separate but internally continuous subintervals of time as in instantaneous and natural sampling . The signal that results from a sampling process is called a sampled-data signal. The signals resulting from ideal sampling are also referred to as discrete-time signals. Each of the three basic sampling types occurs at different places within a DSP system. The output from a sample-and-hold amplifier or a digital-to-analog converter DAC is an instantaneously sampled signal. In the output 117 118 Chapter Seven Figure An analog signal a and three different types of sampling 6 ideal c instantaneous and d natural. of a practical
