19–22
Altera Corporation
Stratix GX Device Handbook, Volume 2
September 2004
Finite Impulse Response (FIR) Filters
clock, the users needs to load coefficients of the polyphase filter h1(n) and
so on.
Table 19–10 summarizes the coefficient loading schedule. The
output, y(n), is clocked using the 4
× clock.
Table 19–10. Polyphase Interpolation (I=4) Filter Coefficient Loading
Schedule
Cycle of 4
× Clock
Coefficients to Load
Corresponding RAM/ROM
1, 5,...
h(0), h(4), h(8), h(12)
0, 1, 2, 3
2, 6,...
h(1), h(5), h(9), h(13)
0, 1, 2, 3
3, 7,...
h(2), h(6), h(10), h(14)
0, 1, 2, 3
4, 8,...
h(3), h(7), h(11), h(15)
0, 1, 2, 3