The AD9851 from Analog Devices does direct digital sythesis of radio frequency signals. This application uses an Arduino UNO with a TJCTMP24024 LCD TFT Touchscreen to provide a friendly RF signal generator.
Touch above or below each digit to increment or decrement (with auto-repeat), or touch a digit and drag up or down to adjust it. Both operations carry to the higher digits.
This application uses the standard Arduino SPI library, and the Adafruit libraries for GFX and to drive the ILI9341 LCD display.
The TJCTMP24024 LCD has an XPT2046 touch-screen however, and I have a custom fork of Paul Stoffregen's driver:
The libraries for AD9851 and Touchscreen Events use C++ templates: