42 | Keysight | FieldFox Handheld Analyzers 4/6.5/9/14/18/26.5/32/44/50 GHz - Data Sheet
USB Power Sensor Measurements versus Frequency (continued)
Source frequency span must be equal to 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.
Src sweep direction
Forward f2src > f1src
Forward f2src > f1src
Rx sweep direction
Forward f2rx > f1rx
Reverse f2rx > f1rx
Frequency calculations
Receiver frequency = Source frequency ± Offset
Receiver frequency = Offset — Source Frequency Offset > Source frequency
See FieldFox Configuration Guide for option information. Many capabilities listed in this Data Sheet require options.
Description
Measurements
Source power, gain/loss and receiver (Rx) power
Gain = Rx power / source power (memory). Source power (memory) is measured during setup.
Refer to the test port output power typical data on page 5.
Output power
Dynamic range
The dynamic range with FOPS is dependent on FieldFox’s output power and the power sensor’s dynamic range.
Supported USB power sensors: www.keysight.com/find/fieldfoxsupport
The graph below shows a filter measurement using two different power sensors, the U2002A (—60 to +20 dBm) and the U2021XA
(—45 to +20 dBm). While a filter is not commonly measured using FOPS, it is a useful device for demonstrating dynamic range.
For both measurements, the FieldFox source power was set to —1 dBm, the maximum available in the selected frequency range of
7.25 to 13.25 GHz. An external amplifier was not used in this case, but one can be added to increase the source power and hence
dynamic range.
Example showing typical dynamic range of FOPS
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