MODUL Function
VIII - 42
Function Generators
MODUL Modulation function (GX 320 only)
The MODUL function modulates a carrier frequency (FM) or amplitude (AM).
The modulating signal can be:
•
either internal (INTernal source, sinusoidal 1 kHz signal)
•
or on VCG IN, for an EXTernal source.
The carrier specifications are defined in the same way as the CONT function.
Using an EXTernal source the signal must have an amplitude of ± 10 Vpp
and a frequency of < 15 kHz (FM) and < 5 kHz (AM).
Depending on the voltage the modulation is as follows:
-
AM:
the output signal amplitude is typically
100 % for -10 V
50 % for 0 V
null for 10 V
-
FM:
the output signal frequency is typically
Freq
start
for -10 V
(Freq
start
+ Freq
end
) / 2 for 0 V
Freq
end
for +10 V
Remarks
•
For AM: with LOGIC and square signals modulation is digital:
the modulating signal is read at a frequency of 150 kHz. This
amplitude (256 values) pilots the output signal amplitude.
For the other types of signal modulation is analogue and the
modulating signal cannot exceed 5 kHz.
•
For AM: with the SINE and TRIANGLE signals, TTL OUT is not available
•
For FM: modulation is digital: the modulating signal level is read at a
frequency of 65 kHz.
This amplitude (256 values) is then converted into frequency.
Connections
Selection of
modulation source
Pressed successively selects the INTernal source
or the EXTernal source
.
Modulated output
signal
TTL OUT
Pilot signal
± 10 V; F < 5 kHz