REQUIRES OPTION 302 (POWER SENSOR SUPPORT) - SOLD SEPARATELY

This feature allows FieldFox’s source frequency to be set independently from the power sensor (receiver) frequency. With frequency-offset using a 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), the user should ensure that only the signal of interest is present at the power sensor input and that all other signals are filtered appropriately.

Setup parameters

• Source frequency: Center/span or start/stop
• Receiver frequency: Range determined by power sensor range
• Frequency offset: Positive offset or negative offset
• Frequency step size: 30 kHz minimum
• Number of points: 2 to 1601 (Combination of number of points and frequency step size limited by span)
• Dwell time/point: 0 to 1.0 sec

The source frequency span must be equal to the receiver frequency span.

Receiver sweep direction: forward (default setting) or reverse.

For some DUTs, the output frequency may sweep in a reverse direction, as compared to the source frequency. The basic relationships between the source, receiver, and offset frequencies are shown in the table below. The FieldFox analyzer includes an offset calculator that ensures a fast measurement setup.