The HP Model 8552B Spectrum Analyzer IF Section was designed to be used in conjunction with an RF Section and a Display Section. The complete analyzer is a highly sensitive superheterodyne receiver with spectrum scanning capabilities determined by the RF Section. Output video from the receiver circuits is applied to the CRT in the display section; thus, a signal or group of signals can be analyzed in the frequencydomain. Input signals are plotted on the CRT as a function of amplitude verstis frequency. The amplitude (Y-axis) of the CRT is calibrated in absolute units of power (dBm) or voltage (juV/mV); accordingly, absolute and relative measurements of both amplitude and frequency can be made. The instrument controls are arranged for easy operation. For wide spectrum analysis, the operator can use the preset scan of the RF Section used, or for a more detailed study, the spectrum width can be progressively narrowed. The frequency scan can be stopped to allow use of the instrument as a fixed frequency receiver. The RF Section’s widest bandwidth is automatically selected for preset scan operation; for variable scan and fixed frequency operation, narrower band-widths can be selected by the operator.