Advertisement
5.
If
the signal you wish to observe is so weak that even the 5 m V position
of the VOLTS/DIV switch cannot produce sufficient trace height for trig
gering or a useable display, pull the corresponding VARIABLE control knob
(PULL
X
5MAG switch) (15) or
CI6).
This produces 2 mV/div sensitivity
when the VOLTS/DIV switch is set to
10
mV, and 1 m V / div when it is set
to 5 mY. However, the channel bandwidth decreases to 7 MHz, and the
trace noise may become noticeable when this is done.
6.
If
the signal you wish to observe is to high in frequency that even the
.2 uS position of the A TIME/DIV switch results in too many cycles dis
played, pull the A VARIABLE knob to activate the PULL
X
10 MAG switch (27).
This increases the effective sweep speed by a factor of ten, so .2 uS
becomes 20 nSfdiv, .5 uS become 50 nSf div, etc. 0.2 and
0.5,uS
MAG are uncalibrated,
IpS
is calibrated and below.
7. If
the signal you wish to observe is either DC or low enough in frequency
that AC coupling attenuates or distorts the signal, flip the AC/GND/DC
switch (11) or (12) to DC.
CAUTION : If the observed waveform is
low-level AC, make certain it is not
riding on a high-amplitude DC voltage.
You will also have to reset the Trigger MODE switch (30) to NORM if the
signal frequency is below 25 Hz, and possibly readjust the Trigger LEVEL
control (34).
2-3-3
Dual-trace Operation
Dual-trace operation is the major operating mode of the Model 7040A. The setup
for dual-trace operation is identical to that of 2-3-2 Single-trace Operation
with the following exceptions :
1. Set the V MODE switch (21) to either ALT or CHOP. Select ALT for relatively
high-frequency signals (A TIME/DIV switch set to .2mS or faster). Select
CHOP for relatively low-frequency signals (A TIME/DIV switch set to .5 mS
or slower)
2.
If
both channels are displaying signals of the same frequency, set the Trigger
SOURCE switch (32) to the channel having the steepest-slope waveform. If
the signals are different but harmonically related, trigger from the channel
carrying the lowest frequency. Also, remember that if you disconnect the
channel serving as the trigger source, the entire display will free run.
Advertisement
