The 7L5 is a 5 MHz spectrum analyzer with digital storage. Frequency stability is within 5 Hz/hr and center frequency (dot) can be read with six digit accuracy immediately after turn-on. There is no need to fine tune the display. Complex measurements and analysis can be made with relative ease. Built-in micro-processing circuits decode control settings, process frequency and reference level information, and optimize sweep time and resolution for the selected frequency span. The 7L5 with 80 dB or more of spurious free dynamic range, provides the ability to measure wide relative amplitudes. Nanovolt sensitivity provides very low-level signal and noise measurements. The 7L5 display is fully calibrated in dBm, dBV, or volts/d iv. The reference level can be accurately set to 1 dB increments. A front panel input buffer control increases front-end immunity to intermodulation distortion while maintaining a constant reference level. To accommodate a wide variety of impedance sources, the 7L5 uses quick disconnect plug-in input impedance modules of 50 0, 75 Q, 600 O, 1 MO/28 pF and customized units to meet special requirements. Digital storage allows any 7000-Series mainframe, with crt readout, to present clean, easy to photograph, displays. A smooth integrated display provides an accurate analysis of most displays. Two complete displays can be held in memory for comparison. Two modes select either the conventional peak display or a digitally averaged display.