sta002 STMicroelectronics, sta002 Datasheet - Page 17

• Manufacturer Part Number: sta002
• Description: Starmano Channel Decoder
• Manufacturer: STMicroelectronics

TABLE 1. Timing loop parameters (m= 22; K
Carrier frequency registers (CARINTG)
Internal address: 94 H
Reset Value: 00H
This register is formed by the 8 integrator MSBs
of the carrier loop filter.
The value of this register, when the system is
locked, is an image of the frequency offset.
It may be read or written at any time by the micro.
When written the integrator LSBs are reset.
Carrier NCO frequency setting register (IFFREQ)
Internal address: 93 H 92 H 91 H 90 H
Reset Value
IFFREQ4
IFFREQ3
IFFREQ2
IFFREQ1
This register is divided into four bytes.
The LSB byte is named IFFREQ1, the MSB is
named IFFREQ4.
MSB
MSB
MSB
MSB
MSB
b31
b23
b15
b7
b7
alpha_tmg
b30
b22
b14
beta_tmg
b6
b6
fn(Hz)
b29
b21
b13
b5
b5
: 00H C1H 1DH 37H
signed number
b28
b20
b12
b4
b4
0
1
2
3
4
5
6
7
b27
b19
b11
NA
NA
NA
NA
NA
NA
NA
NA
NA
b3
b3
0
b26
b18
b10
0.71
1.42
2.85
5.70
11.4
22.8
45.6
b2
b2
NA
25
1
b25
b17
b1
b9
b1
0.50
1.01
2.01
4.03
8.06
16.1
32.2
NA
36
2
D
LSB
LSB
LSB
LSB
LSB
b24
b16
b0
b8
b0
= 0.356; M_CLK = 39.02687179MHz)
0.36
0.71
1.42
2.85
5.70
11.4
22.8
NA
51
3
For example if M_CLK = 39.02687179MHz,
Fck = M_CLK/4
The 26 bits value to be written into this register is
given by:
which is the Reset Value.
Actual Carrier Frequency Register (CARFREQ)
Internal address: 96 H, 97 H, 98 H
CAR FREQ 3
CAR FREQ 2
CAR FREQ 1
This register contains the actual carrier frequency
value when the system is locked.
It is divided into 3 registers: CARFREQ3, down to
1 (CARFREQ3 is the MSB).
This register may be read at any time and it is
useful to store the value of the recovered carrier.
If the system unlocks (due, to a lack of signal
etc.) the carrier NCO could be initialized with this
value to speed-up the tracking process.
3.4.2 Loop parameters
Like the timing loop the carrier loop is a second
0.25
0.50
1.01
2.01
4.03
8.06
16.1
MSB
MSB
MSB
NA
72
b23
b15
4
b7
Damping factor
IFFREQ = 12655927 = (C11D37)
0.18
0.36
0.71
1.42
2.85
5.70
11.4
b22
b14
b6
102
NA
5
IFFREQ
b21
b13
b5
0.13
0.25
0.50
1.01
2.01
4.03
8.06
144
NA
6
b20
b12
b4
0.09
0.18
0.36
0.71
1.42
2.85
5.70
204
NA
INT
7
b19
b11
b3
F
IF
0.06
0.13
0.25
0.50
1.01
2.01
4.02
288
ck
NA
8
2
b18
b10
b2
26
0.04
0.09
0.18
0.36
0.71
1.42
2.85
408
NA
9
b17
b9
b1
HEX
STA002
0.03
0.06
0.13
0.25
0.50
1.01
2.01
577
NA
LSB
LSB
LSB
10
b16
17/43
b8
b0