Signal generator is must have tool on your working table. Buying one may be too expensive especially if you are hobbyist. So why not to build one. There are many generator chips available. One of them is Analog Devices AD9835 Direct Digital Synthesis (DDS) generator chip which is capable to generate sine wave up to 50MHz.
This signal generator is programmed to output frequencies from 1Hz up to 10Mhz with 1 Hz step resolution. Generator is controlled with three pushbuttons while information is displayed on one sliding window LED display. DDS generator is controlled via PIC16F628 microcontroller.