Digital Signal Processing Reference
In-Depth Information
//
bs1750.cof
IIR bandstop coefficient file, centered at 1,750 Hz
#define stages 5 //number of 2nd-order stages
int a[stages][3]= {
//numerator coefficients
{27940, -10910, 27940},
//a10, a11, a12 for 1st stage
{32768, -11841, 32768},
//a20, a21, a22 for 2nd stage
{32768, -13744, 32768},
//a30, a31, a32 for 3rd stage
{32768, -11338, 32768},
//a40, a41, a42 for 4th stage
{32768, -14239, 32768} };
int b[stages][2]= { //denominator coefficients
{-11417, 25710},
//b11, b12 for 1st stage
{-9204, 31581},
//b21, b22 for 2nd stage
{-15860, 31605},
//b31, b32 for 3rd stage
{-10221, 32581},
//b41, b42 for 4th stage
{-15258, 32584}
};
//b51, b52 for 5th stage
FIGURE 5.15.
Coefficient file for a tenth-order IIR bandstop filter designed with MATLAB
in Appendix D (
bs1750.cof
).
FIGURE 5.16.
Output frequency response of a tenth-order IIR bandstop filter centered at
1750 Hz, obtained with an HP signal analyzer.
shown in Figure 5.17. Verify that the filter's output is an IIR bandpass filter
centered at 2 kHz. Figure 5.18 shows the output frequency response of this
36th-order IIR bandpass filter, obtained with an HP analyzer.
2.
Rebuild this project using the coefficient file
lp2000.cof
(on the CD), which
represents an eighth-order IIR lowpass filter with a 2-kHz cutoff frequency
(also designed with MATLAB). Verify the output of this IIR lowpass filter.
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