HSP50214BVI Intersil, HSP50214BVI Datasheet - Page 19

• Manufacturer Part Number: HSP50214BVI
• Manufacturer: Intersil

Specifications of HSP50214BVI

• Lead Free Status / RoHS Status: Not Compliant

NOTE: While Halfband filters are typically selected starting with the last stage in the filter chain to give the maximum alias free bandwidth,
Depending on the number of halfbands used, PROCCLK
must operate at a 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
(6)(HB4)(2
(5)(HB3)(2
(4)(HB2)(2
(3)(HB1)(2
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.
PROCCLK
COEFFICIENTS
S
a higher throughput rate may be obtained using other filter combinations. See Application Note 9720, “Calculating 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
(HB4 + HB5)
(HB3+HB4+HB5)
(HB2+HB3+ HB4+HB5)
(HB1+HB2+HB3+HB4+HB5)
S
≥ ([(7)(HB5)(2
)+
- 0.031303406
- 0.031303406
0.000000000
0.281280518
0.499954224
0.281280518
0.000000000
HALFBAND #1
S
)+
HB5
is the input sampling frequency,
19
)+
)+
)]/2
T
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
(EQ. 10)
HSP50214B
-0.00130558
-0.06055069
-0.06055069
-0.00130558
0.000000000
0.012379646
0.000000000
0.000000000
0.299453735
0.499954224
0.299453735
0.000000000
0.000000000
0.012379646
0.000000000
HALFBAND #3
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
255-Tap Programmable FIR Filter
The Programmable FIR filter can be used to implement real
filters with even or odd symmetry, using up to 255 filter taps,
or complex filters with up to 64 taps. The FIR filter takes
advantage of symmetry in coefficients by summing data
samples that share a common coefficient, prior to
multiplication. In this manner, two filter taps are calculated
per multiply accumulate cycle. Asymmetric filters cannot
share common coefficients, so only one tap per multiply
accumulate cycle is calculated. The filter can be effectively
bypassed by setting the coefficient C
coefficients, C
N
= 0.
-0.003810883
-0.069904327
-0.069904327
-0.003810883
0.000378609
0.000000000
0.000000000
0.019245148
0.000000000
0.000000000
0.304092407
0.500000000
0.304092407
0.000000000
0.000000000
0.019245148
0.000000000
0.000000000
0.000378609
HALFBAND #4
0
= 1 and all other
-0.000347137
-0.010158539
-0.081981659
-0.081981659
-0.010158539
-0.000347137
0.000000000
0.00251317
0.000000000
0.000000000
0.03055191
0.000000000
0.000000000
0.309417725
0.500000000
0.309417725
0.000000000
0.000000000
0.03055191
0.000000000
0.000000000
0.00251317
0.000000000
HALFBAND #5
May 1, 2007
FN4450.4
S
.
S
.