The Keysight N9912A-208 is the frequency offset using power sensor option (FOPS) for the N9912A. PLEASE NOTE, THIS OPTION REQUIRES OPTION 302 (SOLD SEPARATELY).

FOPS is accessed through (and requires) Option 302 USB Power Meter Mode. With both options installed, you can send a signal with the FieldFox internal source at one frequency, and measure this signal with a Keysight U-Series USB Power Sensor at another frequency.

This feature allows the FieldFox source frequency to be set independently from the power sensor (receiver) frequency. With frequency offset using power sensor (FOPS), the frequency of both the source and receiver are swept, and the two track each other. The offset frequency can be negative, zero, or positive.

FOPS can be used to characterize the scalar transmission response of devices such as mixers and converters. This frequency offset capability is necessary for conversion loss/gain measurements on frequency-translating devices since, by definition, the input and output frequencies of the DUT are different. The FieldFox source stimulates the DUT and the power sensor is used as the measurement receiver.

Since power sensors are inherently broadband devices (not frequency-selective), it is your responsibility to ensure that ONLY the signal of interest is present at the power sensor input and that all others signals are filtered appropriately.

For some DUTs, the output frequency may sweep in a reverse direction, as compared to the source frequency. The FieldFox analyzer includes an offset calculator that ensures a fast measurement setup.