Analog Modulations
R&S
®
SMA100B
74
User Manual 1178.3834.02 ─ 03
4 Analog Modulations
The R&S
SMA100B supports AM (amplitude modulation), FM (frequency modulation),
Φ
M (phase modulation (PhiM)), and also PULM (pulse modulation). It generates low
frequency signals (LF) as sine, triangle, trapezoidal or square (pulse) waveform, that
can be output and further processed by a downstream instrument.
4.1 Required Options
R&S
SMA100B base unit equipped with the following options:
●
Option frequency (R&S
SMAB-B10x)
●
Option pulse modulator (R&S
SMAB-K22)
●
Option pulse generator (R&S
SMAB-K23)
(supports generation of single and double pulse signals)
●
Option multi-function generator (R&S
SMAB-K24)
●
Option pulse train generator (R&S
SMAB-K27)
(requires R&S
SMAB-K23)
●
Option AM/FM/PhiM, up to 6 GHz (R&S
SMAB-K720)
For more information, see data sheet.
4.2 Modulation Types and Signal Sources
Radio transmitters do not transmit an audio signal directly. Instead, they modulate the
audio signal onto a continuous wave (CW) carrier with much higher frequency.
A CW carrier has a sinusoidal waveform with constant amplitude and constant fre-
quency. Modulating a signal onto the carrier means varying a property of the carrier
according to the modulating signal. The three basic modulation types FM, AM and
PhiM for example, vary one property of the carrier proportional to the instantaneous
amplitude of the modulating signal.
Signal sources
If fully equipped, the R&S
SMA100B modulates signals from the following sources:
●
Internal modulation source
–
Two LF generators
Supplie sinusoidal and square waves in the frequency range 0.1
Hz to 10
MHz
and selectable shapes.
The R&S
SMA100B generates any other modulation signal shapes (triangle,
trapezoid and square wave or a pulse signal) by converting the sinusoidal sig-
nal
–
Multifunction generator and a noise generator
Modulation Types and Signal Sources
