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AD9361 tx spectrum is always wrong, is always three spectrum

Question asked by rf2685 on Mar 6, 2015
Latest reply on Mar 9, 2015 by tlili

AD9361Tx channel, DDR, an LVDS model, configuration register x010 = 0 c8, 0 x012 = 10,tx spectrum is always wrong,For example, configuration tx  frequency of 2 GHz signal, using FPGA to produce 1MHz dds carrier, the spectrum is always three lines, 1999MHz, 2GHz, 2001 MHz, and have some other spur signals, and when  configure different HB1, HB2, FIR digital filter, then tx spectrum have some changes , but the main frequency still the same.

so My question is what problem cause this phenomenon?Is Digital interface configuration errors or interface timing problems?


And then I use AD9361 loop test configuration register,0x3F4, Configuration to launch mode,0x3F4=0XC3, the spectrum is  right.

and Another problem is How to use the loop test receiving loop, how data interface configuration, OX3F4 or 0 x3f5 registers how to set up? How to operate can be tested?