Last night I finished a new signal generator S/W for an RFzero, ATSAMD21G18 that is also used in the Arduino Zero, for controlling an Si5351A. The signal generator can besides the standard carrier also generate two-tone, I/Q, H3A, spread spectrum and function as a sweep generator. It is also possible to control a LPF bank and various attenuators making the output level variable. The frequency, amplitude, output mode and more can be controlled from rotary encoders and a keypad.
See more here:
Bo
www.rudius.net/oz2m :: www.rfzero.net
Bo, OZ2M