R&S SMJ100A, Operating Manual

Page: 311 / 874

Instrument Function
R&S
®
SMJ100A
295 Operating Manual 1403.7458.32 ─ 14
State - AWGN
Activates/deactivates the RFI signal generator. The interferer (AWGN or CW interferer,
depending on the selected mode) is generated as after the generator is activated.
Remote command:
[:SOURce<hw>]:AWGN:STATe
on page 579
Mode - AWGN
Selects the mode for generating the interfering signal.
"Additive Noise"
The AWGN noise signal with selectable system bandwidth is added
to the baseband signal.
"Noise Only" The pure AWGN noise signal with selectable system bandwidth is
modulated to the carrier. The connection to the baseband is interrup-
ted.
"CW Interferer" A sine with a defined frequency offset is added to the baseband sig-
nal. The calculation of E
b
/N
0
ratio is omitted.
Remote command:
[:SOURce<hw>]:AWGN:MODE
on page 576
System Bandwidth - AWGN
(Additive Noise and Noise Only)
Sets the RF bandwidth to which the set carrier/noise ratio relates.
Within this frequency range, the signal is superimposed with a noise signal whose
power corresponds exactly to the set C/N or S/N ratio.
Note: The noise signal is not generated arbitrarily for a particular bandwidth, but
instead it is generated in steps. Noise therefore also occurs outside the set system
bandwidth.
Remote command:
[:SOURce<hw>]:AWGN:BWIDth
on page 572
Minimum Noise/System Bandwidth Ratio - AWGN
(Additive Noise and Noise Only)
Sets the ratio of minimum noise bandwidth to system bandwidth.
Note: The noise signal is not generated arbitrarily for a particular bandwidth, but
instead it is generated in steps. Noise therefore also occurs outside the set system
bandwidth.
With this parameter the minimum real noise bandwidth can be set as required by some
standards. It does not influence the calculation of power from the set C/N or S/N ratio
in relation to system bandwidth.
The overall bandwidth is calculated as follow and may not exceed 80 MHz.
Overall Bandwidth = System BW x Minimum Noise/System BW Ratio
Remote command:
[:SOURce<hw>]:AWGN:BWIDth:RATio
on page 573
Impairment of Digital I/Q Signal and Noise Generator - AWGN/IMP Block