The Waterman POCKETSCOPE model S—15—A is an oscilloscope containing two cathode ray tubes with independent signal inputs which permit simultaneous observation of any two voltages with respect to the same time base. Other voltages may be substituted for the time base depending upon the information desired and the ability of the operator to interpret the resultant pattern. The cathode ray tubes are the Waterman developed 3SP1 type. Each tube screen is 1 1/2 inches high by 3 inches wide permitting great economy of space. While both tubes have equal operating potentials, each has its own beam, focus, vertical and horizontal positioning controls. VERTICAL CHARACTERISTICS Each vertical amplifier has a maximum sensitivity of 10 millivolts RMS (.028 volts DC) per inch and a frequency response which is flat within —2db from DC to 180KC. Its pulse rise time is equal to approximately 1.8 microseconds. In addition to the amplifiers non-frequency discriminating gain control, a compensated step attenuator permit additional attenuation of 1000, 100, 10 and 1. A fixed calibration voltage of 20 millivolts RMS at line frequency is provided as a position on the vertical attenuator. TIME BASE The sweep frequency is variable from 0.5 cycles to 50KC and may be operated in either the repetitive or trigger mode. Synchronization is from either internal or external sources regardless of polarity. TIME BASE AMPLIFIER The horizontal amplifiers have a maximum sensitivity of 1.0 volt RMS per inch and a frequency response which is flat within —2db from DC or 0 cycles to 150KC. Their pulse rise time is equal to 3.0 microseconds. Each amplifier has its own non-frequency discriminating gain control in addition to three steps of compensated attenuation 100, 10 and 1. The output of the linear time base generator is connected to either or both horizontal amplifiers by rotating their II ATT switch in the extreme counterclockwise position (SW). A fixed calibration voltage of 5 volts RMS at line frequency is provided as a position on the horizontal attenuator. BLANKING Provisions are made for connecting or disconnecting the internal blanking pulse. This thus provides a means for externally modulating the beam. CATHODE RAY TUBE CONTROL Individual vertical and horizontal positioning as well as beam and focus controls are provided for each cathode ray tube. PHYSICAL CHARACTERISTICS Convenient and functional layout of all controls and terminals permits maximum flexibility with minimum of complexity. The width is 6 inches, the depth is 12 inches and the height is 7 inches. Its weight is but 16 1/4 pounds.