The 3745B Selective Level Measuring Set is designed to meet the requirements of operators and manufacturers of high-density FDM systems. The 3745B is a processor-controlled, synthesizer-based, high-quality tuneable receiver which can measure True RMS levels between +15 dBm and -125 dBm, in the frequency range of 1 kHz to 25 MHz. Features selective filters for pilot, channel, and group measurements, and automatic tuning according to selected FDM plans.