R&S SMJ100A, Operating Manual

Page: 314 / 874

Instrument Function
R&S
®
SMJ100A
298 Operating Manual 1403.7458.32 ─ 14
Bit Rate - AWGN
(Additive Noise)
Sets or indicates the bit rate used for converting C/N or S/N to E
b
/N
0
.
With "Custom Digital Mod" signals, the bit rate used is indicated here. It is defined by
the choice of the standard in the "Custom Digital Mod" menu.
With "Digital Standard" signals, the bit rate used for converting C/N or S/N to E
b
/N
0
is
set here.
When generating a "Digital Standard", it is thus possible to select which bit rate is to be
used for calculating the ratio of bit energy to noise power density, e.g. the bit rate
before or after channel coding.
Remote command:
[:SOURce<hw>]:AWGN:BRATe
on page 572
Carrier/Noise Ratio / Signal/Noise Ratio
(Additive Noise and CW Interferer only)
Sets the carrier/noise, signal/noise or signal/inerferer ratio.
Whether a configuration of C/N or S/N is enabled, depends on the selected "Display
Mode".
●
In "Carrier Reference Mode", this entry determines the RFI power and thus the
power of the output signal. It does not affect the power of the useful signal, i.e. the
carrier power remains constant.
●
In "Noise Reference Mode", this entry determines the power of the useful signal,
i.e. the carrier power. The RFI power remains constant.
●
The power of the noise signal which is derived from the entered C/N or S/N value
is displayed under "Noise Power". The value is displayed automatically in the units
of the useful signal.
●
The power of the useful signal is displayed in the menu under "Carrier Power" and
can also be changed there. The displayed value corresponds to the value in the
"Level" display field.
●
The power of the output signal is displayed under "C Noise Power".
If "Set Noise Power via E
b
/N
0
" is selected, the associated C/N or S/N value is displayed
here.
Remote command:
[:SOURce<hw>]:AWGN:CNRatio
on page 573
E
b
/N
0
- AWGN
(Additive Noise)
Sets the ratio of bit energy to noise power density in "Additive Noise" mode.
●
In "Carrier Reference Mode", this entry determines the noise power and hence the
power of the output signal, that means the c noise signal. It does not affect
the power of the useful signal. The carrier power is kept constant.
●
In "Noise Reference Mode", this entry determines the power of the useful signal,
i.e. the carrier power. The noise power is kept constant.
●
The power of the noise signal which is derived from the entered E
b
/N
0
value is dis-
played under "Noise Power (System Bandwidth)". The value is displayed automati-
cally in the units of the useful signal.
Impairment of Digital I/Q Signal and Noise Generator - AWGN/IMP Block