AD9873JS datasheet(13/39 Pages) AD

13 / 39 page

REV. 0

AD9873

–13–

0Fh, Bit 4, Bit 5: Profile Select

The AD9873 quadrature digital upconverter is capable of storing

four preconfigured modulation modes called profiles that define

a transmit frequency tuning word and cable driver amplifier con-

trol. Profile Select bits <1:0> or PROFILE [1:0] pins program

the current register profile to be used. Profile Select bits should

always be 0 if PROFILE pins are used to switch between pro-

files. Using the Profile Select bits as a means of switching between

different profiles requires the PROFILE pins to be tied low.

10h–1Fh: Burst Parameter

Tx Frequency Tuning Words

The frequency tuning word (FTW) determines the DDS-

generated carrier frequency (fC) and is formed via a concatenation

of register addresses. Bit 7 of register address 1Ah is the most

significant bit of the profile 2-frequency tuning word. Bit 0 of

2-frequency tuning word.

The output frequency equation is given as:

fC = (FTW

× fSYSCLK)/224.

Where fSYSCLK = Mx fOSCIN and FTW < 80 00 00 h

Changes to FTW bytes immediately take effect on active profiles.

Cable Driver Gain Control

The AD9873 dedicates three output pins that directly interface to

the AD832x-family of gain programmable cable driver amplifier.

This allows direct control of the cable driver’s gain via the

AD9873. New data is automatically sent to the cable driver

amplifier whenever a new burst profile with different gain setting

becomes active or when the gain contents of an active AD8321/

AD8323 gain control register changes. Default value is 00h

(lowest gain).

AD9873JS 数据表(PDF) 13 Page - Analog Devices