Keysight 11715A AM/FM Test Source
The major components of the 11715A are a low-noise voltage-controlled oscillator (VCO), 2 digital dividers, and a double-balanced mixer. The VCO is the primary signal source, with a typical frequency range of 330 to 470 MHz at the FM output. FM is produced by directly coupling the external modulation source to the VCO’s tune input, providing very wide bandwidth modulation with low phase shift. This design also ensures very little incidential AM. The Keysight 11715A can also be used in conjunction with an 8901A/B and an 8902A as a calibrated signal source for special applications. In particular, the U.S. commercial FM broadcast band of 88 to 108 MHz is covered by the FM divide-by-4 output of the 11715A.