The Model 855 is a phase coherent multiple-output, ultra-fast switching and low phase noise signal generator with a frequency range from 300 kHz to 6, 12, or 20 GHz, and is ideally suited for a wide range of applications where good signal quality, accurate and wide output power range are required. Excellent phase noise is combined with good spurious and harmonic rejection and a leading-edge switching speed of 25 micro-seconds. A high-stability OCXO reference provides excellent frequency accuracy and stability. The generator accepts a wide range of external references including the range from 1 to 250 MHz or higher frequency clocks to 3 GHz. It comes in a standard 19” 1U (up to 4 channels) or optionally 3U (8 channels) enclosure and offers various control interfaces like USB, LAN, or GPIB.