R&S FSMR, Operating Manual

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Analyzer - Bandwidths and Sweep Time R&S FSMR
1166.3363.12 4.8-4 E-1
SWEEP TIME
MANUAL
The SWEEPTIME MANUAL softkey activates the manual data entry for the
sweep time. At the same time, the coupling of the sweep time is cancelled.
Other couplings (
VIDEO BW, RES BW ) remain effective.
In the frequency domain (span > 0 Hz) and for resolution bandwidths above 1
kHz, the allowed sweep times for spans > 3.2 kHz range from 2.5 ms through
to 16000 s. With spans below 3.2 kHz, the maximum allowed sweep time is
reduced to 5 s * span/Hz.
If FFT filters are used, the sweep time is fixed by the span and the bandwidth
and therefore cannot be set.
In time domain (span = 0 Hz), the range of sweep times is 1
D s to 16000 s is
selectable in steps of max. 5% of the sweep time. For numeric inputs, rounding
is made to the nearest possible sweep time. For rollkey or UP/DOWN key
inputs, the sweep time is adjusted in steps either downwards or upwards.
The manual input mode of the sweep time is indicated by a green asterisk (*)
on the display. If the selected sweep time is too short for the selected
bandwidth and span, level measurement errors will occur. This happens
because the available settling time for the resolution or video filters is too short.
In this case, the R&S FSMR outputs
UNCAL on the display and marks the
indicated sweep time with a red asterisk (*).
IEC/IEEE-bus command:
SENS:SWE:TIME:AUTO OFF;
SENS:SWE:TIME 10s
RES BW
AUTO
The RES BW AUTO softkey couples the resolution bandwidth to the selected
span. Changing the span causes automatic adjustment of the resolution
bandwidth.
Automatic coupling of resolution bandwidth to span is always recommended
when a favourable setting of the resolution bandwidth in relation to the selected
span is desired for the measurement under request.
The coupling ratio is set in the COUPLING RATIO submenu.
The RES BW AUTO softkey is only available in the frequency domain (span >
0 Hz). The softkey is blanked in the time domain.
IEC/IEEE-bus command:
BAND:AUTO ON
VIDEO BW
AUTO
The VIDEO BW AUTO softkey couples the video bandwidth to the resolution
bandwidth. If the resolution bandwidth is changed, the video bandwidth is
automatically adjusted.
The coupling of the video bandwidth is always recommended
when the
minimum sweep time is required for a selected resolution bandwidth
. Narrower
video bandwidths require longer sweep times due to the longer settling time.
Wider bandwidths reduce the signal/noise ratio.
The coupling ratio is set in the COUPLING RATIO submenu.
The coupling of the video bandwidth to the resolution filter is also permitted for
the time domain display (span = 0).
IEC/IEEE-bus command:
SENS:BAND:VID:AUTO ON