In summary, onsemi offers a wide variety of Clock Generators, Clock Synthesizers, and other Data Distribution Products. Clock generators do exactly what the name implies, which is generate a clock signal. They are separated into Crystal Oscillators and Voltage Controlled Crystal Oscillators. Clock synthesizers are similar to clock generators, but they do not integrate a XTAL. Spread Spectrum Clocks are devices that actively suppress emissions, but do not affect signal integrity.