R&S ESCI Analyzer - MKR FCTN
1166.6004.12 4.129 E-1
The R&S ESCI uses the following correction factors to evaluate the noise
density from the marker level:
• Since the noise power is indicated with reference to 1 Hz bandwidth,
the bandwidth correction value is deducted from the marker level. It is
10 x lg (1 Hz/BW
Noise
), where BW
Noise
is the noise or power bandwidth of
the set resolution filter (RBW).
Sample detector:
• As a result of video filter averaging and trace averaging, 1.05 dB is
added to the marker level. This is the difference between the average
value and the RMS value of white noise.
• With a logarithmic level axis, 1.45 dB is added additionally. Logarithmic
averaging is thus fully taken into account which yields a value that is
1.45 dB lower than that of linear averaging.
RMS detector:
• With the exception of bandwidth correction, no further corrections are
required for the RMS detector since it already indicates the power with
every point of the trace.
To allow a more stable noise display the adjacent (symmetric to the
measurement frequency) points of the trace are averaged.
In time domain mode, the measured values are averaged versus time
(after a sweep).
IEC/IEEE-bus command: CALC:MARK:FUNC:NOIS ON;
CALC:MARK:FUNC:NOIS:RES?
Example: Measurement of inherent R&S ESCI noise
[PRESET] The R&S ESCI is set to default setting.
[MARKER] Marker 1 is switched on and set to the maximum value
of the displayed spectrum. Set marker to desired
frequency using the rotary knob.
[NOISE] The R&S ESCI switches the sample detector on and
sets the video bandwidth to 300 kHz (0.1 x RBW). The
power density level of inherent noise is displayed in
dBm/Hz in the marker info field.
Note: The R&S ESCI noise figure can be calculated from the
measured power density level. It is calculated by deducting
the set RF attenuation (RF Att) from the displayed noise level.
174 is to be added to the result to obtain the R&S ESCI noise
figure.
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