Atec Rohde-Schwarz-SMP Series - Manual (Page 5)

Microwave Signal Generator SMP 5
Pulsed Transmitter
Pulse Generator
Display
LO RF
Sideband
Filter
Circulator
Pulse 1
2
Antenna direction pulse
FIG 5: Radar tests (switch position 1 for testing the distance indicated by radar,
switch position 2 for testing the antenna direction indicated by radar)
internal single or double pulses with
pulse frequencies up to 10 MHz.
The pulse generator can also be triggered
externally, pulse width and delay being
user-selectable over a wide range.
Simultaneous modulation modes
and their application
All modulation modes which the SMP is
able to generate can be combined (in the
case of SMP03/04 with some restrictions
regarding pulse and amplitude modula-
tion). Highly complex signals can thus be
generated for modern communication
and radar systems.
Doppler effects
The combination of pulse modulation and
FM DC simulates Doppler effects and also
chirp signals.
Pulse radar with rotating antenna
Combined scan and pulse modulation
provides the type of signals occurring in
pulse radar applications with rotating
antenna.
In the example shown in Fig. 5, the exter-
nal pulse from the pulse generator or
radar display is applied to the external
pulse input of the SMP and used as a trig-
ger for the internal pulse generator and
modulator.
The main advantage of this kind of trigger
is that it can be delayed to simulate dis-
tance and direction and to check the val-
ues on the display.
Fading
Simultaneous frequency and amplitude
modulation can be used to study fading
effects of FM receivers.
Sweep capabilities
Level sweep
The 20 dB level sweep of the SMP is an
efficient function for determining power
characteristics and for compression
measurements.
Digital frequency sweep
The digital frequency sweep with steps
from 10 ms is a useful facility for measur-
ing the frequency response of microwave
modules or antennas.
Sweep modes
The digital sweep can be executed auto-
matically in repetitive mode or in single-
shot mode with selectable sweep time.
Manual sweeping (STEP MODE) within
the sweep limits is also possible. Trigger
inputs and outputs facilitate synchronous
operation in conjunction with other
instruments.
Use in EMC measurements
Functions qualifying the SMP for EMC
applications include the trigger facility for
step-by-step sweeping, marker outputs
and, above all, the extension of the fre-
quency range to 10 MHz (option SMP-B11).
The capability of compensating external
frequency responses is also an important
feature.
Frequency hopping in list mode
One of the very special features of the
SMP is the list mode. Unlike the normal
sweep mode with increasing or decreas-
ing frequencies, the list mode can be
used for programming frequency hop-
ping. A list editor makes programming
extremely easy. Up to 2003 pairs of fre-
quency and level values can be stored in
lists.
Of course, the same types of sweep can
be executed in the list mode as in the nor-
mal sweep mode.
Frequency response
compensation
Power amplifiers, cables, antennas and
TEM cells usually exhibit a relatively large
frequency response which has to be com-
pensated to obtain accurate measure-
ment results.
The SMP provides two excellent tools for
the correction of external frequency
responses:
◆ User-defined correction of external
frequency responses
◆
External level control using a power
meter