The 3586B selective level meter and HP 3336A/B tracking synthesizer offer the high performance necessary to meet demanding requirements in the design, manufacture, commissioning, and maintenance of frequency division multiplex (FDM) systems. Features of the HP 3586B selective level meter include wideband power measurements and telephone impairment measurement of impulse noise, phase jitter, noise with tone, and signal-to-noise with tone ratios. The wide frequency coverage to 32.5 MHz allows measurements at both voice Channel and carrier frequencies.