Motorola DSP56156 Manual page 164

If a unity gain is expected from the A/D section, the gain of that filter has to be multiplied
by 1/1.104 in order to compensate the attenuation of the comb filter at the given decima-
tion ratio (refer to Table 6-17).
Table 6-18 Coefficient of the Filter Shown in Figure 6-29
; Source filter file: "compad105.IIR.Filter"
_filter_type
_NSTAGES
Figure 6-30 shows the overall response of the A/D section cascaded with the DSP IIR filter
described above.
MOTOROLA
APPLICATION EXAMPLES
equ BIQUAD_FILTER_TYPE
equ 4
dc $01ac
; Biquad stage no. 1
dc $d625
dc $4001
dc $00b7
dc $197a
; Biquad stage no. 2
dc $db34
dc $58d6
dc $0069
dc $183a
; Biquad stage no. 3
dc $c8c9
dc $2f54
dc $e8e8
dc $d922
; Biquad stage no. 4
dc $c5a7
dc $7996
dc $e7fd
dc $d812
DSP56156 ON-CHIP SIGMA/DELTA CODEC
; number of biquadratic stages
; g = 0.0261528436/2
; -d2_1 = -0.6539936028/2
; -d1_1 = 1.000075495/2
; n2_1 = 0.01115530244/2
; n1_1 = 0.3980984016/2
; -d2_2 = -0.5749677665/2
; -d1_2 = 1.388032237/2
; n2_2 = 0.00643072253/2
; n1_2 = 0.3785165879/2
; -d2_3 = -0.8627144322/2
; -d1_3 = 0.7394786413/2
; n2_3 = -0.3608584886/2
; n1_3 = -0.6072824655/2
; -d2_4 = -0.9116724841/2
; -d1_4 = 1.89978731/2
; n2_4 = -0.3751780353/2
; n1_4 = -0.6238880148/2
6 - 49