Keysight U2781A User Manual

Keysight U2781A User Manual Manual pdf 37 page image

Features and Functions 2Keysight U2781A User’s Guide 37System Reference ClockThe 10 MHz reference clock can come from two sources; internal backplaneoscillator and external clock source.The internal oscillator on the USB backplane supplies an independent 10 MHzsystem reference clock to each of the USB slot. This 10 MHz reference clock isdriven through an independent buffer. Refer to Figure 2-3 for the block diagram.Every clock trace is in equal distance to ensure that the distance of the slot to theslot skew is minimized. Users can use this common reference clock signal tosynchronize multiple modules in a measurement or control system.The default SCPI command of ACQuire:RSIGnal AUTO will scan through anddetect if there is any valid clock source from the external BNC connector. If none isfound, then the internal 10 MHz clock source will be used.The SCPI command below will direct the reference clock source to the internal10 MHz:ACQuire:RSIGnal INT