User manual

Table Of Contents
3152B User Manual Publication No. 980935 Rev. M
3-32 Operation Astronics Test Systems
Controlling the
Carrier Frequency
In general, when you select a modulation scheme, the
waveform
being modulated (the carrier) is always a sine wave. When
you
select the modulation function but set the modulation type to “Off
,
the output generates an un-modulated, continuous waveform
(CW)
signal. The frequency setting of the carrier in modulation mode
is
not the same as for standard waveform mode
and must be
programmed separately. Use the following command to program
the carrier frequency:
mod:carr <value> Set
the CW frequency in units of Hz. The
same value will be used for all modulation
functions.
Controlling the
Carrier Base Line
As explained above, the Advanced Trigger mode allows the 3152B
output to “idle” when it has f
inished a waveform segment and is
waiting for the next trigger event. The output signal
during this time
is called the baseline.
The 3152B offers two options for the base line:
1) Carrier (un-modulated, CW carrier)
2) DC Level
Use the following command to control the carrier base line:
mod:carr:bas carr Selects continuous wave (CW)
when the
modulated function idles between trigger
events.
mod:carr:bas dc Selects continuous DC level
when the
modulated function idles between trigger
events.
Using the Digital
Pul
se Generator
The digital pulse generator function provides a way to set up pulse
trains and associated parameters in units of time.
The pulse train is built in the same memory that stores
arbitrary
waveforms. Therefore, changing from arbitrary to digital p
ulse
mode, and vise-versa, may overwrite arbitrary
waveforms that were
previously downloaded. Use the command below to se
lect the
digital pulse function:
func:mod dpul Selects
the digital pulse function. If you have
not changed parameters, then the output
will
generate a single pulse with the following
default settings: 10 ms period, 0-5
V
amplitude, 10 ms high time, 1 ms
rise time,
and 1 ms fall time.
From this point, you may
change one or more of the pulse
parameters while the signal is being output. Since the pulse is