hsp50214 Intersil Corporation, hsp50214 Datasheet - Page 16

• Manufacturer Part Number: hsp50214
• Description: Programmable Downconverter
• Manufacturer: Intersil Corporation

NOTE: While Halfband filters are typically selected starting with the last stage in the filter chain to give the maximum alias free
Depending on the number of halfbands used, PROCCLK
must operate a some minimum rate above the input sample
rate, F
number of multiplies for each of the halfband filter stages.
The filter calculations take 3, 4, 5, 6, and 7 multiplies per
input for HB1, HB2, HB3, HB4, and HB5 respectively. If we
keep the assumption that f
then Equation 10 shows the minimum ratio needed.
f
PROCCLK
COEFFICIENTS
S
bandwidth, a higher throughput rate may be obtained using other filter combinations. See Application Note 9720, “Calculat-
ing Maximum Processing Rates of the PDC”.
, to the halfband. This relationship depends on the
C10
C11
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
C22
C0
C1
C2
C3
C4
C5
C6
C7
C8
C9
/f
S
(6)(HB4)(2
(5)(HB3)(2
(4)(HB2)(2
(3)(HB1)(2
([(7)(HB5)(2
- 0.031303406
- 0.031303406
0.000000000
0.281280518
0.499954224
0.281280518
0.000000000
HALFBAND #1
(HB4 + HB5)
(HB3+HB4+HB5)
(HB2+HB3+ HB4+HB5)
(HB1+HB2+HB3+HB4+HB5)
S
HB5
is the input sampling frequency,
)+
)+
TABLE 4. HALFBAND FILTER COEFFICIENTS
)+
-0.049036026
-0.049036026
0.005929947
0.000000000
0.000000000
0.29309082
0.499969482
0.29309082
0.000000000
0.000000000
0.005929947
HALFBAND #2
)+
)]/2
(EQ. 10)
T
HSP50214
16
where:
HB1 = 1 if this section is selected and 0 if it is bypassed;
HB2 = 1 if this section is selected and 0 if it is bypassed;
HB3 = 1 if this section is selected and 0 if it is bypassed;
HB4 = 1 if this section is selected and 0 if it is bypassed;
HB5 = 1 if this section is selected and 0 if it is bypassed;
T = number of Halfband Filters Selected. The range for T is
from 0 to 5.
Examples of PROCCLK Rate Calculations
Suppose we enable HB1, HB3, and HB5. Using Figure 16,
HB1= 1, HB3 = 1, and HB5 = 1. Since stage 2 and stage 4
are not used, HB2 and HB4 = 0. PROCCLK must operate
faster than (7x2+5x4+3x8)/8 = 7.25 times faster than f
If all five halfbands are used, then PROCCLK must operate at
(7x2+6x4+5x8+4x16+3x32)/32 = 7.4375 times faster than f
-0.000000000
-0.012379646
-0.000000000
-0.00130558
-0.00130558
-0.000000000
-0.012379646
-0.000000000
-0.06055069
-0.000000000
-0.299453735
-0.499954224
-0.299453735
-0.000000000
-0.06055069
HALFBAND #3
-0.000378609
-0.000000000
-0.003810883
-0.000000000
-0.019245148
-0.000000000
-0.069904327
-0.000000000
-0.304092407
-0.500000000
-0.304092407
-0.069904327
-0.000000000
-0.019245148
-0.000000000
-0.003810883
-0.000000000
-0.000378609
0.000000000
HALFBAND #4
-0.000347137
-0.000000000
-0.00251317
-0.000000000
-0.010158539
-0.000000000
-0.03055191
-0.000000000
-0.081981659
-0.000000000
-0.309417725
-0.500000000
-0.309417725
-0.000000000
-0.081981659
-0.000000000
-0.03055191
-0.000000000
-0.010158539
-0.000000000
-0.00251317
-0.000000000
-0.000347137
HALFBAND #5
S
.
S
.