Other Parts Discussed in Thread: TPS54227, TLV62565, DAC3484
My customer is using our DAC3482 in a signal generator project. We measured the spectrum of the output signal and found there are side band signals around.
1. input clk=500MHz, PLL=2 so DACCLK=1GHz
2. Datarate=500Msps, interpolation=2 so sample rate=1Gsps.
3. NCO is shutdown
When we set the output signal frequency to 10MHz, the spectrum is as below: The central frequency(maker 1)=10MHz, -20.169dBm. The side band signal (maker 3/maker 2) is=10.008MHz, -72.958dBm / 10.017MHz, -77.146dBm
When we set the output signal frequency to 20MHz, the spectrum is as below: The side band signal is=20.008MHz, -68.069dBm / 20.017MHz, -72.019dBm
So can you help analyze why the side band signal will show up and how to get rid of it? Thanks.