T h e m o d u l a t i o n f u n c t i o n a n d s w e e p f u n c t i o n c a n b e u s e d
simultaneously. Therefore, it's possible to output a frequency hopping
signal. For frequency hopping, the hopping frequency is set with the
sweep function and the modulation signal is set with the modulation
function.
The figure below shows an example where the hopping frequency
interval is 2MHz and the modulation signal is FSK.
Overwrite screen of signal analyzer MSA538
■
Handheld signal analyzer MSA538
■
Frequency
：
20kHz to 3.3GHz
With Fast Fourier Transform (FFT) and conven
-
tional sweep systems, each strong point of both
systems is usable.
REAL TIME system enables unsteady signal
measurement, time domain analysis and modu
-
lation analysis. SWEEP system enables mea
-
surement over wide span.
List setting of FSK modulation/direct mode
Meanwhile, the modulation signal
source is a list.
The right figure shows
the spectrum waveform of FSK (direct
mode).
The list edit screen is shown below.
List edit screen of FSK modulation/direct mode
(2) Direct mode
The shift amount of the frequency or phase stored in the modulation
signal memory is read out at the specified transmission rate. The trans
-
mission rate can be set in the range from 100Hz to 20kHz at 100Hz step.
Compared with register mode, the transmission rate is slower, but the
arbitrary signal can be output.
Transmission rate
FSK/PSK signal
List data is written.
100Hz to 20kHz/point
100Hz step
Frequency/phase conversion
Modulation signal memory
2k×32bit
Example of modulation signal:
FSK(direct mode)
Burst control
Simultaneous use with sweep function
The burst control is a function for outputting a signal intermittently. Valid
in FSK and PSK. AM is valid only in free run.
The period in which the signal is not output is carrier-off and is set to the
minimum level.
(1) Control mode
Free run
Continuous output (Burst control off)
External
The signal of "TRIG IN" connector on the front panel is
control signal.
High : signal output, Low : carrier off.
Manual
The control signal is generated by the manual trigger
key TRIG .
Signal output/carrier off signal is generated.
(2) Operation mode
There are single and repeat.
Control
signal
Carrier off level
Carrier off level
Top data
Top data
Top data
Final data
Final data
Output
signal
Synchronous
output
Output
signal
Synchronous
output
Control
signal
Repeat
Single
