FIFQ2 - FIFQ1 (DCO Fine Frequency)

Address

: 2C-3A

Type

: R/W

Reset

: 1100 0100 for FIFQ2 - 1100 0111 for FIFQ1

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

CHANNEL 2 or CHANNEL 1 DCO FINE FREQUENCY (8LSB’s)

The DCO’s, which are set to the carrier frequency to be demodulated, are adjusted in two parts as follows :

C

=

Fc

Fs

⋅ 48, where Fc is the carrier frequency, Fs is the crystal frequency

Take the nearest integer, Ci, for the 6 bits of the COFQ register

F

=(C − Ci) ⋅







2

9

3







Take the nearest integer, Fi, for the 8 bits of the FIFQ register.

Common frequencies with Fs = 27MHz :

Fc (MHz)

Ci

Fi

decimal

binary

decimal

binary

5.5

10

001010

-38

11011010

5.74

10

001010

35

00100011

5.85

10

001010

68

01000100

6.0

11

001011

-57

11000111

6.552

12

001100

-60

11000100

ACOEFF2 - ACOEFF1 (PLL Loop Filter Proportional Coefficient)

Address

: 2D-3B

Type

: R/W

Reset

: 10010000 for ACOEFF2 - 0010 0011 for ACOEFF1

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

DMD SW2 or 1

0

COARSE A2 or A1

SIGN A2 or A1

FINE A2 or A1

DMD SW

: Mode switch : 0 = FM, 1 = QPSK

COARSE A,

SIGNA, FINE A

: Program the PLL (FM/QPSK carrier recovery) loop filter proportional coefficient A :

A coefficient = coarse + (sign x fine)

COARSE

Value

00

0

01

1

10

1/2

11

1/4

SIGN

0+

1-

FINE

Value

000

0

001

1/2

010

1/4

011

1/8

100

1/16

101

1/32

110

1/64

111

Not used

PROGRAMMING THE DEVICE (continued)

STV8203

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