This is most practical item I've ever made!!!!

Now I made another version. This board can generate arbitral frequency signal from 1 MHz to 200 MHz with Silicon Labs Si5356 with GPS trained 8 MHz clock. Si5356 can be programmed (I2C command can be published) from ATmega88A (indeed, 328 is too much for this job) and 4-outputs can have different frequency.

Indeed any time domain related "precision conscious" measurement instrument has "10 MHz IN" terminal. They are the standard clock input and connecting this board setting 10 MHz to such an instrument will provide "atomic clock precision" in time domain measurement. Not only connecting measurement instrument, just for the purpose of high precision frequency standard for any frequency up to 200 MHz, this board will be quite useful.

The I2C command publishing by ATmega88A is done through, actually, Arduino sketch. Si5356 requires lots, bunch, many register setting containing input signal source frequency, output signal and lots of property but we can send them step by step as is written by Arduino sketch..

Actual operation can be found in the following movie. Please note that, 40 MHz waveform is not "real" one due to lack of oscilloscope BW (it is just 40 MHz). Already I've confirmed its "real" waveform by more wider BW oscilloscope and it was more "square-wave form" than in this movie.

Again, this is the most practical item I've ever made. Any 70's 80's 90's time domain related instrument (VNA, SPA, oscilloscope, SG) with 10 MHz input will get the atomic clock precision from GPS by ultra low cost!

If this appears on my tindie store, it will be less than $50...