US Navy Contract No. N00104-15-D-D004 The Keysight E8257N is a fully-synthesized signal generator with high output power, low phase noise, and optional ramp sweep capability. Specifications apply over a 0 to 50 °C range, unless otherwise stated, and apply after a 45 minute warm-up time. Supplemental characteristics, denoted as typical, nominal, or measured, provide additional (non-warranted) information at 25 °C, which may be useful in the application of the product. Unless otherwise noted, this data sheet applies to units with serial numbers ending with 55060000 or greater.