SI5351 DDS filtering 

In this video I will demonstrate how a cheap dds signal generator can be filtered in such way will attenuate the second harmonic by 114 decibels over carrier.
For this purpose, I used a cheap si5351, a 5 poles bandpass filter and 2 notch filters!
I know Icom IC7300 S-meter is not the ideal tool to measure such values, but for the time being I am happy with it, so here it is!
From 1.8 megahertz up to 3.6, the signal drops from S9 plus 60 dB, down to S0 wich is about 114 dB. The generator itself produce the second harmonic at minus 20, minus 30 dB over carrier, therefore the filter total attenuation is between 70 and 80 dB.