Specifications

SIGNAL
CONNECTIONS
Probes
Generally.
probes
offer the
most
convenient means
of
connecting
an
input
signal
to
the instrument.
They
are
shielded to
prevent pickup
of
electrostatic
interference.
The
supplied
10X
probe
offers a
high
input impedance, which
minimizes
circuit loading
and allows the circuit under
test
to
operate
very
close
to
normal
conditions
thus
providing
accurate
measurements.
Conversely, it also
attenuates
the
input
signal amplitude by
a
factor
of
10.
Coaxial
Cables
Cables may also be used to
connect signals to the
input
connectors and
may have
a
considerable effect on the
accuracy
of a displayed waveform.
To
maintain
the original
frequency
characteristics
of an applied signal,
only
high-
quality,
low-loss
coaxial cables should
be
used. Also,
cabling should be terminated
at both
ends
in its characteris-
tic
impedance.
lf this is
not
possible,
use
suitable
i
m
pedance-match
i n
g
devices.
PROBE
COMPENSATION
Misadjustment
of
probe
compensation is
one
of
the
greatest
sources of
operator error. Most
attenuator
probes
are
equipped with
compensation adjustments. To ensure
optimum
measurement
accuracy,
always
compensate
your
probe
before
making measurements. Probe
compensation is
accompl
ished
as
fol
lows :
1. Set the appropriate VOLTS/DlV
switch to
0.1
V and
the
AC-GND-DC
switch to DC.
2.
Preset
instrument controls and
obtain a
Normal
Sweep
Display
presentation (see
Basic Oscilloscope
Displays section
of
this manual) using
the
ell
kHz
CALIBRATOR
square-wave output as the
input
signal. Display
several
cycles
of the CALIBRATOR
square-wave at approximately four divisions
amplitude.
3. Check the
waveform
presentation
for
overshoot
and
rolloff. Readjust,
if necessary,
the
probe
com-
pensation
for flat
tops
on the
waveforms
(see
Figure
1 1
).
Refer
to the appropriate
probe
manual for
compensation
adjustment instructions.
@
4658/DM44
Operators
35