STA002 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

STA002

STARMAN™ CHANNEL DECODER

STMicroelectronics 

STA002

TABLE 1. Timing loop parameters (m= 22; KD = 0.356; M_CLK = 39.02687179MHz)

beta_tmg

fn(Hz)

alpha_tmg

0

1

2

3

4

5

6

7

8

9

10

NA 25

36

51

72 102 144 204 288 408 577

Damping factor

0 NA NA NA NA NA NA NA NA NA NA NA

1 NA 0.71 0.50 0.36 0.25 0.18 0.13 0.09 0.06 0.04 0.03

2 NA 1.42 1.01 0.71 0.50 0.36 0.25 0.18 0.13 0.09 0.06

3 NA 2.85 2.01 1.42 1.01 0.71 0.50 0.36 0.25 0.18 0.13

4 NA 5.70 4.03 2.85 2.01 1.42 1.01 0.71 0.50 0.36 0.25

5 NA 11.4 8.06 5.70 4.03 2.85 2.01 1.42 1.01 0.71 0.50

6 NA 22.8 16.1 11.4 8.06 5.70 4.03 2.85 2.01 1.42 1.01

7 NA 45.6 32.2 22.8 16.1 11.4 8.06 5.70 4.02 2.85 2.01

Carrier frequency registers (CARINTG)

Internal address: 94 H

Reset Value: 00H

MSB

b7 b6

b5 b4 b3 b2

signed number

LSB

b1 b0

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.

The 26 bits value to be written into this register is

given by:

IFFREQ

=

INT

 IF





Fck

226



For example if M_CLK = 39.02687179MHz,

Fck = M_CLK/4

IFFREQ = 12655927 = (C11D37)HEX

which is the Reset Value.

Actual Carrier Frequency Register (CARFREQ)

Internal address: 96 H, 97 H, 98 H

Carrier NCO frequency setting register (IFFREQ)

Internal address: 93 H 92 H 91 H 90 H

Reset Value : 00H C1H 1DH 37H

MSB

LSB

b31 b30 b29 b28 b27 b26 b25 b24

IFFREQ4

MSB

LSB

b23 b22 b21 b20 b19 b18 b17 b16

IFFREQ3

MSB

LSB

b23 b22 b21 b20 b19 b18 b17 b16

CAR FREQ 3

MSB

LSB

b15 b14 b13 b12 b11 b10 b9 b8

CAR FREQ 2

MSB

LSB

b7 b6 b5 b4 b3 b2 b1 b0

CAR FREQ 1

MSB

LSB

b15 b14 b13 b12 b11 b10 b9 b8

IFFREQ2

MSB

LSB

b7 b6 b5 b4 b3 b2 b1 b0

IFFREQ1

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.

This register is divided into four bytes.

The LSB byte is named IFFREQ1, the MSB is

named IFFREQ4.

3.4.2 Loop parameters

Like the timing loop the carrier loop is a second

17/43

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