HDM8515P datasheet(48/75 Pages) HYNIX

48 / 75 page

6. Register Definitions

6.1 Write Registers

ADDRESS (Hex)

00, 01, 02

Symbol Timing Frequency

The 20 bit straight binary number in this field establishes the symbol

timing frequency utilized within the demodulator. Bit 7 of address 00 is

the MSB and bit 4 of address 02 is the LSB. If Rs is the symbol rate

and fc is the clock frequency, the value to be stored in this 20 bit field is

the integer portion of Rs(2

20)/fc.

Symbol Timing Loop Gain Control

This field establishes the K1 and K2 gain values for the second order

loop filter of the symbol tracking loop. Bits 0,1,2 and 3 determine the

straight-through gain, and bits 4,5,6 and 7 determine the integration

path gain. The nominal value of this parameter in Hex, is expressed

below for different ranges of symbol rate to clock rate ratios:

Clock/Symbol Rate

Value

04, 05, 06

Carrier Frequency

The 20 bit, two's complement number in this field establishes the

nominal carrier frequency of the demodulator. Bit 7 of address 04 is the

MSB and bit 4 of address 06 is the LSB. The number in this 20 bit field

multiplied by the clock frequency divided by 2

20 is the carrier frequency

in Hertz. When the carrier sweep function is active, this value defines

the starting frequency.

HDM8515P Datasheet(PDF) 48 Page - Hynix Semiconductor