STV8203 ST Microelectronics, STV8203 Datasheet - Page 28

• Manufacturer Part Number: STV8203
• Description: MULTISTANDARD TV SOUND DEMODULATOR
• Manufacturer: ST Microelectronics

STV8203
PROGRAMMING THE DEVICE (continued)
SCOEFF (Symbol Tracking Loop Filter Coefficients)
Address
Type
Reset
DMX-OF : Symbol tracking control : 0 = QPSK, 1 = FM.
PLF_A
PLF_B
SRF (Symbol Tracking Loop Frequency)
Address
Type
Reset
This register provides access to the control signal for the symbol tracking loop (2’s complement). If read,
it indicates a value proportional to the symbol tracking frequency error. If written to, it will preset the
frequency error.
RESET
After a reset sequence, all the registers controllable by AUTOSTANDARD function (FIR, COFQ, FIFQ,
ACOEFF, BCOEFF, SCOEFF, SRF) are adjusted for the standard I configuration (channel 1 to FM mono
mode and channel 2 to QPSK mode).
28/31
DMX-OF
bit 7
bit 7
: A coefficient (proportional)
: B coefficient (integral)
In QPSK mode, the symbol tracking loop is closed.
Programme the symbol tracking loop filter proportional coefficient A :
Program the symbol tracking loop filter integral coefficient B :
: 2F
: R/W
: 0001 1100
: 30
: R/W
: 0000 0000
bit 6
bit 6
0
10000000
00000000
01111111
SRF [7:0]
bit 5
PLF_A [5:3]
PLF_B [2:0]
bit 5
000
001
010
011
100
101
110
111
000
001
010
011
100
101
110
111
SYMBOL RECOVERY FREQUENCY
PLF_A
bit 4
bit 4
bit 3
bit 3
Approx. Error (kHz)
bit 2
bit 2
+8
-8
Not used
0
1/1024
Value
Value
1/128
1/256
1/512
1/16
1/32
1/64
16
32
0
1
2
4
8
0
PLF_B
bit 1
bit 1
bit 0
bit 0