I’m working on building blocks that can be used for larger designs. One of those building blocks is a DDS signal generator using the Si5351. I added a low pass filter to the output of CLK0. This filter starts rolling off at 50mhz. Elsie generated the schematic and I normalized the values to smd capacitors I had and Murata rf chip inductors I purchases.
L1, L2, and L3 are smd inductors that cost about USD$0.20 each.
Here is what the Si5351 output looks like with Adafruit’s example library sketch.
This is the output after the low pass filter. Second and third harmonics are still there, but there is definite improvement.
