The Tektronix R7903 Oscilloscope is a solid state, high performance instrument designed for general-purpose applications. This instrument includes a readout system which provides alphanumeric information; encoded by the Plug-In to be displayed on the cathode-ray tube. This instrument accepts Tektronix 7-series Plug-In units to form a complete measurement system. The two compartments on the left are connected to the vertical deflection system. Electronic switching between the vertical Plug-In compartments allows a multi-trace vertical display. The right Plug-In compartment is connected to the horizontal deflection system. The flexibility of this Plug-In feature and the variety of Plug-In units available allow this system to be used for many measurement applications. The R7903 features a Cathode-ray tube with a fast writing rate and small spot size. The graticule size is 8 X 10 centimeters. An option is available for a pulsed readout display and pulsed graticule lights. This provides maximum use of the photographic speed of the film in the single shot mode. On the rear panel are four signal out connectors (SIG OUT, SAWTOOTH, GATE (MAIN & AUX) and SINGLE SWEEP READY INDICATOR), and four input connector (Z-AXIS INPUT, READOUT SS, SINGLE SWEEP RESET and READOUT INHIBIT).