The Tektronix SD20 is a single-channel, 20 GHz loopthrough sampling head designed for low-loss testing in applications such as microwave systems research and development, digital device characterization and high-speed digital communications circuit design. It provides an acquisition rise time of 17.5 ps with typically 750 µVRMS of noise (350 µV with smoothing) to ensure clean, undistorted signals.The SD20 is nonterminated and keeps losses to a minimum by routing the signal of interest directly through the sampling head without the need of a power divider. The SD20 can also be used for customized TDR measurements of transmission lines and controlled impedance devices. An external signal generator may be used, instead of the SD24 step generator, to tailor the TDR stimulus to fit a particular situation. For instance, slower slew rates or higher amplitude may be utilized, or you may perform half-sine or impulse testing.In digital communications, the SD20 is useful for viewing and triggering on the clock signal without the use of a power divider.