MSP3417G datasheet(69/81 Pages) MICRONAS

69 / 81 page

PRELIMINARY DATA SHEET

MSP 34x7G

Micronas

6.3.6. FIR-Parameter, Registers FIR1 and FIR2

Note: The use of this register is no longer recom-

mended. Use it only in cases where software compati-

bility to the MSP 34x7D is required. Using the STAN-

DARD SELECTION register together with the MODUS

MSP 34x7G.

Data shaping and/or FM/AM bandwidth limitation is

performed by a pair of linear phase Finite Impulse

Response filters (FIR-filter). The filter coefficients are

programmable and either are configured automatically

by the STANDARD SELECT register or written manu-

ally by the control processor via the control bus. Two

not necessarily different sets of coefficients are

required: one for MSP-Ch1 (NICAM or FM2) and one

for MSP-Ch2 (FM1 = FM-mono). In Table 6–14 several

coefficient sets are proposed.

To load the FIR-filters, the following data values are to

transferred

bits

time

embedded

LSB-bound in a 16-bit word.

The loading sequences must be obeyed. To change a

coefficient set, the complete block FIR1 or FIR2 must

be transmitted.

Note: For compatibility with MSP 3410B, IMREG1 and

IMREG2 have to be transmitted. The value for

IMREG1 and IMREG2 is 004. Due to the partitioning to

8-bit units, the values 04hex, 40hex, and 00hex arise.

6.3.7. DCO-Registers

Note: The use of this register is no longer recom-

mended. It should be used only in cases where soft-

ware compatibility to the MSP 34x7D is required.

Using the STANDARD SELECTION register together

with the MODUS register provides a more economic

way to program the MSP 34x7G.

When selecting a TV-sound standard by means of the

STANDARD SELECT register, all frequency tuning is

performed automatically.

IF manual setting of the tuning frequency is required, a

set of 24-bit registers determining the mixing frequen-

cies of the quadrature mixers can be written manually

into the IC. In Table 6–15, some examples of DCO reg-

isters are listed. It is necessary to divide them up into

low part and high part. The formula for the calculation

of the registers for any chosen IF-Frequency is as fol-

lows:

INCRdec = int(f/fs ⋅ 2

24)

with: int = integer function

= IF-frequency in MHz

fS = sampling frequency (18.432 MHz)

Conversion of INCR into hex-format and separation of

the 12-bit low and high parts lead to the required regis-

ter values (DCO1_HI or _LO for MSP-Ch1, DCO2_HI

or LO for MSP-Ch2).

Table 6–13: Loading sequence for FIR-coefficients

FIR1

00 01hex (MSP-Ch1: NICAM/FM2)

No.

Symbol Name

Bits

Value

NICAM/FM2_Coeff. (5)

see Table 6–14

NICAM/FM2_Coeff. (4)

NICAM/FM2_Coeff. (3)

NICAM/FM2_Coeff. (2)

NICAM/FM2_Coeff. (1)

NICAM/FM2_Coeff. (0)

FIR2

00 05hex (MSP-Ch2: FM1/AM)

No.

Symbol Name

Bits

Value

1IMREG1

04hex

IMREG1 / IMREG2

40hex

3IMREG2

00hex

FM/AM_Coef (5)

see Table 6–14

FM/AM_Coef (4)

FM/AM_Coef (3)

FM/AM_Coef (2)

FM/AM_Coef (1)

FM/AM_Coef (0)

MSP3417G Datasheet(PDF) 69 Page - Micronas

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