8.7 Linear ramps
69
8.7
Linear ramps
It
is
often
desirable
to
linearly
ramp
a
parameter
without
having
to
specify
the
individual
table
entries
manually.
The
TABLE,RAMP
command provides a convenient way to generate such ramps.
TABLE,RAMP
TABLE,RAMP,ch,param,start,stop,duration,count
Appends table entries to the channel
ch
that linearly ramp
param
from
start
to
stop
in
count
steps,
with each step lasting for the
given
duration
.
param
is one of
FREQ
,
AMPL
or
PHAS
. The
start
and
stop
values can be specified with real units as appropriate for
param
.
The
values
of
the
other
parameters
are
taken
from
the
last
entry
in
the
table.
In
simple
table
mode,
count
entries
are
generated,
whereas in advanced table mode only 3 entries are required.
For example, the command
TABLE,RAMP,1,FREQ,80,100,100us,2000
in
TSB
mode will generate 2000 table entries corresponding to a fre-
quency ramp that sweeps the
RF
frequency from 80 MHz to 100 MHz
in a total time of 200 ms (each step being 10 kHz and taking 100 us).
The command can also be used to specify piecewise-linear envelopes
using the
AMPL
parameter, such as in Listing 8.7 resulting in the
RF
output in Figure 8.5.
MODE,1,TSB
# clear the table
TABLE,CLEAR,1
# define initial conditions (i.e. freq and phase)
TABLE,APPEND,1,80MHz,-30dBm,0deg,1us
# ramp power from
−
30dBm to 0dBm in 100us, then down again
TABLE,RAMP,1,POW,-30,0,1us,100
TABLE,RAMP,1,POW,0,-30,1us,100
# should now have 201 entries
TABLE,ENTRIES,1
# arm the table
TABLE,ARM,1
Listing 8.7:
Example using
TABLE,RAMP
to create an envelope.
Содержание ARF021
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