hsp43168 Intersil Corporation, hsp43168 Datasheet - Page 18

• Manufacturer Part Number: hsp43168
• Description: Dual Fir Filter
• Manufacturer: Intersil Corporation

h(n)
x(n)
C0
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
CSEL0-4
†Tied low.
To operate in this mode, the Dual is configured by writing
112H to Address 000H via the microprocessor interface,
CIN0-9, A0-8, and WR. Data reversal must be enabled (see
Table 2). The 12 unique coefficients for this example are
stored as three sets of coefficients for either FIR cell. For FIR
A, the coefficients are loaded into the Coefficient Bank by
writing [C2, C5, C8, (C11)/ 2], CSEL = 0; [C1, C4, C7, C10],
CSEL = 1; [C0, C3, C6, and C9], CSEL = 2; to address
100H, 101H, 102H, 103H, 108H, 109H, 10aH, 10bH, 110H,
111H, 112H, and 113H, respectively.
SHIFTEN
ACCEN
INA0-9
C1
FIGURE 21. DATA/COEFFICIENT ALIGNMENT FOR 23-TAP
FIGURE 22. CONTROL SIGNAL TIMING FOR 23-TAP
FWRD
TXFR
RVRS
CLK
C2
C3
†
†
†
C4
0
0
C5
0
DECIMATE BY 3 SYMMETRIC FILTER
SYMMETRIC FILTER
C6
1
1
C7
1
C8
2
2
C9
2
C10
3
0
C11
3
18
C10
4
1
C9
4
C8 C7
5
5
2
C6
C5 C4
21
0
20
C3
C2 C1
22
1
21
23-TAPS
23
C0
2
HSP43168
22
Example 6. Dual Decimation Example
The purpose of this example is to give an overview of one of
the more complex applications of the HSP43168. The input
is two data streams (A) and (B) samples. Figure 23 shows
the upper level block diagram of the system being
implemented. The decimation rate was set to N. N-1 is
loaded into the decimation factor in Control Word 000H.
To demonstrate the muxed decimation, lets suppose that the
application requires filter A to be configured as an
even-decimate-by-3 filter and filter B to be configured as a
odd-decimate-by-3 filter. The output data is made of the two
decimated data streams multiplexed together and has a data
rate equal to 2 times the input sampling rate divided by the
decimation factor. Figure 24 shows the data/coefficient
alignment for FIR A and FIR B.
To operate in this mode, Control Word 000H must be written
with a 0x152. Data reversal must be enabled by setting bit 4
of Control Word 001H = 0. The filter set selected by
CSEL0-4 = 0 should be loaded by writing C2, C5, C8, C11,
D2, D5, D8, and (D11)/ 2 into 100H, 101H, 102H, 103H,
104H, 105H, 106H, and 107H. The filter set selected by
CSEL0-4 = 1 should be loaded by writing C1, C4, C7, C10,
D1, D4, D7, and D10 into 108H, 109H, 10aH, 10bH, 10cH,
10dH, 10eH, and 10fH. The filter set selected by
CSEL0-4 = 2 should be loaded by writing C0, C3, C6, C9,
D0, D3, D6, and D9 into 110H, 111H, 112H, 113H, 114H,
115H, 116H, and 117H.
FIGURE 23. MULTIPLEXED DECIMATION BLOCK DIAGRAM
B3, B2, B1, B0
A3, A2, A1, A0
F
S
INB0-9
INA0-9
DECIMATE BY N
HSP43168
2F
OUT9-27
S
/(N+1)
BOUT1
AOUT1
BOUT0
AOUT0