60
Subject to change without notice
M a i n m e n u 2 a n d i t s f u n c t i o n s
With AM the maximum selectable output voltage is
10 V
pp
. If the amplitude selcted is less an offset may
be added. Example: amplitude 8 V
pp
and offset
STOP
STOP
–2 V. It is advisable not to combine both. The out-
put is protected against short-circuit or overload
for about 30sec. Overload means: extern voltage
(AC + DC)
>
15 V or load
<
50 ohms. In worst case the
fi nal stage will be damaged.
FSK frequency shift keying
This modulation type is characterized by the change between
two frequencies. The fi rst is called [F0] or carrier frequency, the
second [F1] or hop frequency. The frequencies of both may be
selected independently. The jump between both will be depen-
dent on the signal on the trigger input terminal TRIG.INP
.
The button [F0] of the menu button group
will call the menu
in which the carrier frequency can be chosen. The button [F1]
will call the menu for the adjustment of [F1]. The FSK function
will be activated by pressing [ON] and deactivated by pressing
[OFF].
While FSK is activated the menu FSK can not be
left. It is therefore advisable to set the parameters
in advance. It is necessary to terminate FSK in
HINT
order to be able to return to the main menu.
FSK-Signal 500 Hz / 2 kHz
The picture shows a 5 V TTL square wave signal and the
associated FSK signal. The carrier frequency is 500 Hz
and corresponds to a High. The hop frequency is 2 kHz and
corresponds to Low.
FSK-Parameters HM8131-2
F1: 4.0000000 kHz
- val + < cur >
F1: 20.0000000 kHz
- val + < cur >
** FSK PARAMETERS **
F0 F1 On
Off
PSK Phase Shift Keying
The modulation type PSK generates a signal which changes
phase upon command of a trigger signal . Selection and para-
meter setting is analogous to the procedure described for FSK.
Both phase values may be set from 0 to 359.9 degr. and are
independent from the signal at the terminal Trig.OUTPUT
on the rear panel. The menu item [Ph 0] determines the phase
during the High level, the item [Ph 1] the phase during the Low
level of the trigger signal.
Button [Ph 0] within the button group
calls the menu in which
the [Ph 0] value is selected, button [Ph 1] the corresponding
one for Ph 1. Pressing [ON] activates, [OFF] deactivates the
function.
The menu PSK can not be left as long as this func-
tion is activated, return to the main menu requires
deactivation. It is therefore advisable to select
HINT
the signal function before activating PSK.
Examples:
Fig. 1 shows a square wave signal of 5 V TTL level and a sine
wave the zero crossings of which are coincident with the slopes
of the former. This signal is hence not phase shifted. The PSK
signal has a phase shift of 0 during the High level and of 70
degr. during the Low level.
PSK Parameters HM8131-2
Phase1: 180.0 deg
- val + < cur >
Phase0: 45.0 deg
- val + < cur >
** PSK PARAMETERS **
Ph0 Ph1 On
Off
Fig. 1:
PSK-
signal:
Ph0
= 0, Ph1
= 70 degr.
Fig. 2:
PSK-
signal:
Ph0
= 70 degr.
Ph1 = 0