R&S ESU Series Operating Manual page 145

R&S ESU
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
favorable 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 deactive in the time domain.
Remote command:
VIDEO BW The VIDEO BW AUTO softkey couples the video bandwidth to the resolution band-
AUTO
width. 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 band-
widths 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).
Remote command:
SWEEPTIME The SWEEPTIME AUTO softkey couples the sweep time to the span, video band-
AUTO
width (VBW) and resolution bandwidth (RBW). The sweep time is automatically
adjusted on any change in span, resolution bandwidth or video bandwidth.
The softkey is only available in the frequency domain (span >0 Hz). It is blanked in
the time domain.
The R&S ESU always selects the shortest sweep time possible without falsifying the
signal. The maximum level error compared to using a longer sweep time is < 0.1 dB.
If additional bandwidth and level errors are to be avoided, the sweep time is to be
set to three times the time offered in coupled mode.
The frequency scan rates required when using the quasipeak detector are defined in
Annex B in CISPR 16-2-x:
Frequency range
IF bandwidth
Frequency scan rate
The SWEEPTIME AUTO function is designed for detectors like sample, max peak or
average. For sweeping with the quasipeak detector a manual setting of the sweep
time should be used at any time.
Remote command:
4.114
BAND:AUTO ON
BAND:VID:AUTO ON
Band A Band B
< 150 kHz 150 kHz to 30 MHz
200 Hz 9 kHz
20 s/kHz 200 s/MHz
SWE:TIME:AUTO ON
Instrument Functions
Analyzer Mode
Band C/D
> 30 MHz
120 kHz
20 s/MHz
Operating Manual 1302.6163.12 - 03