Rohde & Schwarz EMI Test ReceiverESCI - Measurement of Carrier;Noise Ratio C;N and C;N

MEAS - Analyzer R&S ESCI
1166.6004.12 4.176 E-1
Measurement of Carrier/Noise Ratio C/N and C/N
o
Using the carrier/noise measurement function, the R&S ESCI determines the C/N ratio which can also
be shown normalized to a 1 Hz bandwidth (function
C/N
o
).
To determine the noise power, a channel at the set center frequency is examined. The bandwidth of the
channel is fixed by means of the
CHANNEL BANDWIDTH function.
The largest signal in the frequency span is the carrier. It is searched when the function is activated and
is marked by means of the
REFERENCE FIXED marker. The noise power of the channel is subtracted
from the signal level obtained (
C/N), and in the case of a C/N
o
measurement it is referred to a 1 Hz
bandwidth.
There are two methods for measuring the carrier/noise ratio:
1. The carrier is outside the channel examined:
In this case, it is sufficient to switch on the desired measurement function and to set the channel
bandwidth. The carrier/noise ratio is displayed on the screen.
2. The carrier is inside the channel examined:
In this case, the measurement must be performed in two steps. First, the reference measurement is
performed with the carrier being active. This is done by switching on either the C/N or the C/N
o
measurement and waiting for the end of the next measurement run . Then, the carrier is switched off so
that only the noise of the test setup is active in the channel. The carrier/noise ratio is displayed after the
subsequent measurement has been completed.
The
ADJUST SETTINGS function facilitates the selection of the frequency span appropriate for the
channel bandwidth: it automatically sets the
SPAN to approx. 4 x channel bandwidth.
The RMS detector is enabled when the power measurement is switched on (
TRACE-DETECTOR-
RMS)
.
Submenu
MEAS – C/N, C/N
o
:
C/N
C/No
CHANNEL
BANDWIDTH
F
C/N
C/No
ADJUST
SETTINGS
The C/N, C/No softkey opens the submenu for configuring the
carrier/noise ratio measurement.
The user can choose between measurement without (C/N) and
measurement with reference to the bandwidth (C/No). In addition,
it is possible to select the bandwidth of the channel and to adapt
the span.
Note:
The measurements are only available in the frequency domain
(span >0)
.