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ad9954  issue

Question asked by adnantahir on Jun 26, 2012
Latest reply on Jun 28, 2012 by adnantahir

i am using AD9954 DDS as a frequency sweep generator from 70MHz to 110MHz ( sweep) . I

measured the output using Spectrum analyzer with the following setting.


resolution band width 100Hz

video band width   100Hz

Span   2MHz


DDS is running with 25Mhz crystal with a multiplying factor of 16. ( system clock 400MHz)

DDS frequency set to 100MHz (fixed).


I think the output spectrum is not correct. There are three frequencies with -5 dbm

level.One peak is at 100Mhz and the two other with +-250khz offset around 100Mhz.

There are also other frequencies but with low level. Can i get a pure output as

shown in the datasheet of the device?