System Design Flow and Fixed-point Arithmetic - Digital Design of Signal Processing Systems: A Practical Approach - page 120

Unquantize coeff 24-bit quantize coeff

1 1

0.5 0.5

0 0

-0.5 -0.5

-1 -1

-1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1

Real Part Real Part

16-bit quantize coeff 12-bit quantize coeff

1 1

0.5 0.5

0 0

-0.5 -0.5

-1 -1

-1 0 1 -1 0 1

Real Part Real Part

Figure 3.25 Effect of coefficient quantization on stability of the system. The system is unstable for
16-bit and 12-bit quantization as some of its poles are outside the unit circle

20

double precision
24-bit
16-bit
12-bit

0

-20

-40

-60

-80

-100

-120

-140

0 0.5 1 1.5 2 2.5 3 3.5

Freq in radian

Figure 3.26 Frequency response of the eighth-order system for different quantization levels