The SynthUSBII from Windfreak is a software tunable RF signal generator that operates from 34.4 MHz to 4.4 GHz. This device also has nonvolatile on board memory so it can be programmed to fire up by itself on any frequency, power, sweep or modulation setting. RF power is controlled by two bits in the PLL chip and there is a total of 10 dB of output power adjustment in 4 steps. The signal generator is controlled and powered by a PC running Windows 7 SP1 to Windows 10 via its USB port. USB communication is done via a virtual comm port directly to the microcontroller. The SynthUSBII can plug straight into your PC.

The software can control multiple devices based on programmed serial numbers, tune an RF CW frequency, run an RF sweep, Pulse Modulate, save many settings to EEPROM, and fine-tune the PLL registers for experienced users. It is ideal for wireless communications systems, microwave point to point backhaul radios, Software Defined Radio (SDR), radar and electronic warfare (EW) applications.