These Analyzers are designed Co provide coverage of three frequency ranges; 10 cps to 20 kc, 35 cps to 100 fcc, and 150 cps to 500kc. models 011, 012 and 013 are provided with calibrated Center Frequency and Dispersion dials, while models 001, 002 and 003 are uncalibrated. These units are designed so that they may be conveniently plugged into any Oscilloscope which accepts the Tektronix letter series plug»ins. By simply installing one of these plug-in units, the Oscilloscope becomes a complete Spectrum Analyzer. In use, the sawtooth output of the Oscilloscope is utilized to provide a signal for sweeping the Spectrum Analyzer Oscillator. Ail voltages for Spectrum Analyzer operation are obtained automatically when the Analyzer is plugged into the oscilloscope.