The Hewlett-Packard Model 3336 Synthesizer/Level Generator is an accurate, stable and spectrally pure sine wave source, producing synthesized frequencies with 11 digits of resolution from 10 Hz to 20.999 999 999 MHz and precise output levels from - 72.99 to + 7.00 dBm (75 ohm output) in .01 dBm steps. A general purpose model and two communications models are available, each having a different combination of balanced and unbalanced outputs, output impedances and output connectors.