The simplest clock generation source is a crystal oscillator. Crystal Oscillators (XOs) are often used to provide single output frequencies in asynchronous applications. Skyworks Solutions Oscillators utilize a crystal plus oscillator to generate a single-ended or differential output frequency for a single component. Crystal oscillator and voltage controlled oscillator (VCXO) products provide fast and easy customization for any frequency. VXCOs are XOs with a varactor diode that allows applied voltage to change or skew the output frequency. Dual, quad and I2C programmable oscillator products can replace multiple discrete oscillators. Unlike a traditional XO where a different crystal is required for each output frequency, Skyworks Solutions XOs/VCXOs use a fixed frequency crystal and DSPLL clock synthesis IC to generate any output frequency to synthesize any frequency from 100 kHz to 1.4 GHz with low phase jitter frequency better than 0.3 ps RMS (or better than 300 femtoseconds). This IC-based approach delivers exceptional frequency stability and reliability, while providing low jitter performance and supply noise rejection specifications that are required for data center, networking, and video applications.