Scans by ArtekMedia © 2007
NOTE:
For versus-chan3. manually-triggered direct recordings, the
TOTAL
TIME
setting is ignored; plotting is stopped by pressing
STOP
. •
TOTAL TIME
also defines the scaling of the positive X-axis for any recording
area used for plotting versus-time measurements. The diagram below
shows a recording area designed for plotting a positive de voltage against
time.
TOTAL TIME
was set to obtain a recording time of
10.0
seconds.
As
a
result the positive X-axis is scaled as shown, extending from
0.0
to
10.0
seconds.
Default Value:
10.0
volts.
TIME ISECONDS)
Range of Selectable Values:
5.0
millivolts to
100.0
volts.
10.0
The channel range settings allow a large scope of input signal amplitudes
to be accurately measured. To obtain optimum accuracy, it is often neces·
sary to set
RANGE
in conjunction with the
OFFSET
setup condition. The effects
of
RANGE
on the recording area should be thoroughly understood, however,
before attempting to use offset conditions.
Setting range on the
HP 7090
is effectively like setting the attenuator on a
voltmeter - accuracy is obtained by choosing a range setting that is suited
to the input signal amplitude. If no offset is used, range should be set equal
to (or somewhat higher than) the absolute value of the largest peak voltage,
positive or negative, expected from the input signaL
To demonstrate the effects of
RANGE
and
OFFSET
on recording areas, a
recording area will be prepared for an example Channel 1 input signal,
Signal
A.
For our present purposes, a recording area will be designed using
TOTAL TIME
and
RANGE
1
only. In the next subsection, which describes the
OFFSET
setup condition, the recording area will be modified to obtain opti
mum accuracy by using the
OFFSET
condition in conjunction with
RANGE.
the X-Axis
Time
SETUP
CONDITION
TOTAL TIME
10.0
SECONDS
The Range Setup
Condition
Measurement Setup Operations 3-9