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Texas Instruments MSP50C614 User Manual

Page 160

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Special Filter Instructions

4-68

Figure 4–7. Filter Instruction and Circular Buffering for N+1 Tap Filter

16 Bits

TAG

AC n+1

AC n+2

AC n

y

if TAG = 1

Rx

even

coeff_array

DP

coeff_array

Rx

even

+1

CORK/FIRK only

COR/FIR only

h[0]

h[1]

h[2]

0

0

0

h[3]

h[4]

0

0

0

h[N–1]

0

0

0

h[N]

0

0

16 Bits

17

th

Bit

coeff_array

coeff_array is stored in
program or data memory
based on filter instruction.

x[k]

x[k–1]

x[k–2]

0

0

0

x[k–3]

x[k–4]

0

0

0

x[k–N]

0

0

1

x[k+1]

0

16 Bits

17

th

Bit

sample_buf

x

x

x

x

x

x

x

+

STAT

x[k–N–1] is replaced
by x[k+1]

y =

Σ

k =0..N

h[

m]

×

x[k–m]

+

R5 = –2(N+1)

program memory (FIRK/CORK)

data memory (FIR/COR)

48-bit accumulation for COR/CORK

32-bit accumulation

for FIR/FIRK

17th Bit

Rx

even