Operating Manual EMI TEST RECEIVER ESIB7 - Rohde & Schwarz

ESIB
Analyzer - Main Markers
Frequency Measurement
To accurately determine the frequency of a signal, the ESIB is equipped with an internal frequency
counter. The frequency counter measures the frequency of the RF signal at the intermediate frequency.
Using the value found at the intermediate frequency, the ESIB calculates the frequency of the RF signal
by applying the known frequency conversion relationships.
The frequency measurement error depends only upon the accuracy of the frequency standard used
(external or internal reference). Although the ESIB always performs the frequency sweep in sync - no
matter what frequency range is set - the frequency counter gives a more exact frequency measurement
than a measurement performed with a marker. This is explained by the following:
• The marker only gives the position of a pixel on the trace and the frequency of the signal is deduced
from this. The trace, however, contains only a limited number of pixels, so each pixel may represent
a number of measurement values that depends on the selected span. This reduces the frequency
resolution.
• The resolution with which the frequency can be measured is proportional to the measurement time.
For measurement time reasons, the bandwidth is normally held as wide as possible and the sweep
time is set a short as possible. This results in a loss of frequency resolution.
For the measurement with the frequency counter, the sweep is stopped at the reference marker, the
frequency is measured to the desired resolution and then the sweep is allowed to continue (see also
Chapter 2, "Measurement Examples").
MARKER NORMAL menu:
SIGNAL
COUNT
The SIGNAL COUNT softkey switches the frequency counter on/off.
The frequency is counted at the position of the reference marker. The sweep
stops at the reference marker until the frequency counter outputs a result.
The time required for a frequency measurement depends on the selected
frequency resolution. The resolution is set in the COUNTER RESOL submenu.
If no marker is enabled when the SIGNAL COUNT softkey is pressed,
MARKER 1 is switched on and set to the trace peak.
The SIGNAL COUNT function is also indicated by [T x CNT] in the marker
field on the display screen.
MARKER 2 [T1 CNT]
-27.5 dBm
23.4567891 MHz
Switching the SIGNAL COUNT function off is accomplished by pressing the
softkey once again.
Note: For digital resolution filters (RBW < 1kHz or softkey RBW 1kHz set to
DIG), a analog prefilter of 2 kHz is active.
IEC/IEEE-bus command
:CALCulate:MARKer:COUNt ON | OFF;
:CALCulate:MARKer:COUNt:FREQuency?
1088.7531.12 4.181 E-15