STV8203 ST Microelectronics, STV8203 Datasheet - Page 26

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

STV8203
PROGRAMMING THE DEVICE (continued)
FIFQ2 - FIFQ1 (DCO Fine Frequency)
Address
Type
Reset
The DCO’s, which are set to the carrier frequencyto be demodulated,are adjusted in two parts as follows :
C
Take the nearest integer, Ci, for the 6 bits of the COFQ register
F
Take the nearest integer, Fi, for the 8 bits of the FIFQ register.
Common frequencies with Fs = 27MHz :
ACOEFF2 - ACOEFF1 (PLL Loop Filter Proportional Coefficient)
Address
Type
Reset
DMD SW
COARSE A,
SIGNA, FINE A
26/31
DMD SW2 or 1
Fc
Fs
bit 7
C
bit 7
Fc (MHz)
6.552
5.74
5.85
48, where Fc is the carrier frequency, Fs is the crystal frequency
Ci
5.5
6.0
: 2C-3A
: R/W
: 1100 0100 for FIFQ2 - 1100 0111 for FIFQ1
: 2D-3B
: R/W
: 10010000 for ACOEFF2 - 0010 0011 for ACOEFF1
2
3
9
: Mode switch : 0 = FM, 1 = QPSK
: Program the PLL (FM/QPSK carrier recovery) loop filter proportional coefficient A :
bit 6
A coefficient = coarse + (sign x fine)
bit 6
0
CHANNEL 2 or CHANNEL 1 DCO FINE FREQUENCY (8LSB’s)
decimal
10
10
10
11
12
bit 5
COARSE A2 or A1
bit 5
COARSE
SIGN
FINE
000
001
010
011
100
101
110
111
00
01
10
11
0
1
Ci
bit 4
bit 4
001010
001010
001010
001011
001100
binary
SIGN A2 or A1
bit 3
bit 3
decimal
bit 2
-38
-57
-60
35
68
bit 2
Not used
Value
Value
FINE A2 or A1
1/16
1/32
1/64
1/2
1/4
1/2
1/4
1/8
0
1
+
0
-
Fi
bit 1
bit 1
11011010
00100011
01000100
11000111
11000100
binary
bit 0
bit 0