The Model 855B Series is a Phase-Coherent Multi-Channel output Fast Switching and Low Phase Noise signal generator with a frequency range from 300 kHz to 6.2 GHz, 12.5 GHz, 20 GHz, 33 GHz, or 40 GHz. Each channel is fully independent that enables the user to tune frequency, power, and phase independently. The 855B leading-edge switching speed of 25μs, combined with a broad power range and good spurious and harmonic rejection, the 855B is ideally suited for a variety of applications where good signal quality and a wide, accurate output power range are required. Excellent phase noise is combined with spurious and harmonic rejection. A high-stability OCXO reference provides excellent frequency accuracy and stability. The generator accepts standard external 10MHz or 100MHz clock references with optional variable reference input that accepts clock frequency ranging from 1 MHz to 250 MHz with 1 MHz increment. Model 855B is designed with scalability in mind, it has dedicated 3 GHz System Reference In and System Reference Out for synchronizing multiple BNC Model 855B units providing infinite synchronized channels.
 
The Model 855B series comes in standard 19-inch 1U rackmount chassis up to 4 channels, or a custom unit 3U benchtop or 19-inch rackmount unit with up to 8 channels, and offers various control interfaces such as USB, LAN, or GPIB. Each interface allows easy and fast communication using the SCPI 1999 command set. Remote control of the instrument can be quickly attained from any host computer using the free and intuitive GUI (Graphical User Interface). In addition, a customer-supplied application programming interface (API) or programming examples for Matlab, Labview, C++, and other commercially available tools make implementation very straightforward.
The Model 855B offers a handy Phase-Coherent Switching option. While you can set the phase relationship between channels (in a fraction of degrees) on the standard unit, the Phase-Coherent Switching option allows users to maintain the phase relationship between channels even while switching frequency.