It's possible to output the three modulation signals of FSK, PSK and AM.
The modulation signal source is equipped in this equipment. Valid only in
"ALC off”.
Modulation function
(1) FSK modulation
In FSK modulation, the frequency shift amount can be set in the range
from 0 to ± 500kHz at 1Hz resolution. The carrier frequency is set in the
center of the shift using the FREQ key.
FSK modulation waveform which is set is displayed in frequency vs. time
on the screen.
Time
Frequency
(2) PSK modulation
In PSK modulation, the phase shift amount can be set in the range from 0
to ± 180 degree by 0.1 degree resolution.
The carrier frequency is set using the FREQ key.
Moreover, PSK modulation waveform which is set is displayed in phase vs.
time on the screen.
Time
Phase
(3) AM(Amplitude Modulation)
The modulation frequency can be set in the range from 100Hz to 5kHz at
100Hz step. The modulation waveform is a sine wave. The modulation
depth can be set at 1% step from 0 to 99%.
In addition, it's valid only in "ALC off" and "FREE RUN" (in other words,
burst control is not allowed).
The AM waveform which is set is displayed in amplitude vs. time on the
screen.
Amplitude
Time
FSK/PSK data mode
There are register mode and direct mode. These modes are valid only in
FSK and PSK.
(1) Register mode
The data transmission rate in this mode is so fast as 1MHz maximum in
comparison with 20kHz in direct mode.
The shift amount of frequency or phase written previously in eight regis
-
ters are read out by modulation signal.
The modulation signal is stored in the modulation signal memory in
which the register numbers are written, and these are read out at the
specified transmission rate.
Modulation signal source can be selected among PN9, PN15 and list.
Fig.1 Waveform by two levels
F
0
F
1
Fig.2 Spectrum of Fig.1
F
0
F
0
F
0
F
0
F
0
F
0
F
1
F
1
F
1
F
2
F
2
F
3
F
3
F
4
F
4
F
5
Fig.3 Filtering Fig.1
(using six registers)
Fig.4 Spectrum of Fig.3
List edit screen of FSK modulation/register mode
[Example] Modulation by two levels
As shown in Fig.1, the modulation by two levels (frequency : F0/F1, phase:
P0/P1) is possible.
However, in case of a rectangular wave, the spectrum will spread as
shown in Fig.2.
Therefore, if generating the filtered waveform using several registers as
shown in Fig.3, the spread of spectrum will be prevented as shown in
Fig.4.
Transmission rate
FSK/PSK signal
Register number
is written.
100Hz to 1MHz/point
100Hz step
Eight registers
Modulation signal memory
2k×3bit
