Tektronix 2236 User Manual

Operators Familiarization - 2236 Operators
CTM MEASUREMENT CONSIDERATIONS
precharging network . This network allows the input coupling
capacitor to charge to the average dc - voltage level of the
signal applied to the probe . Thus any large voltage
transients
that
may
accidentally be
generated will not be
applied to the amplifier input when the input Coupling switch
is moved from GND to AC . The precharging network also
provides a measure of protection to the external circuitry by
reducing the current levels that can be drawn from the ex
ternal
circuitry
during
capacitor
charging
.
Nongated measurements are performed from the A Trig
ger system on signals selected by the A Trigger source
switches . Signals may be applied through the CH 1 input ,
CH 2 , or the
EXT INPUT
connectors
.
Nongated measure
ments may also be performed on the instrument power
source
by
setting the A
SOURCE switch
to LINE
position .
The A TRIGGER LEVEL control , A TRIGGER Mode , A
TRIGGER SLOPE , A & B INT , A SOURCE , A EXT COU
PLING , and BW LIMIT switches are effective in conditioning
the
input
signal .
The following
procedure should
be used
whenever the
probe tip is connected to a signal source having a different
dc level than that previously applied , especially if the dc
level difference is more than 10 times the VOLTS / DIV
switch
setting :
1. Set the Input Coupling switch to GND .
Trigger
status
messages ( “ no A
trig ” and “
no b trig " )
are
not displayed in any mode of the width function so that mea
surement results can be displayed indefinitely . This allows
single
pulse
measurements .
C
U
2. Insert the probe tip into the oscilloscope GND connec
tor and wait several seconds for the input coupling capacitor
to
discharge
.
3. Connect the probe tip to the signal source and wait
several seconds for the input coupling capacitor to charge .
Gated measurements are performed from the B Trigger
system
on
input
signals
being applied
to
either CH
1 , or
CH
2 input connectors . The gate interval ( set by adjusting the
intensified zone
with the B DELAY
TIME
POSITION control
and the B SEC / DIV switch ) must be shorter than the A
Sweep
duration , such
that the
intensified
zone
ends
before
A Sweep
ends
.
The A
TRIGGER
A & B INT
switch
and the
B
TRIGGER
LEVEL
control and
SLOPE
switch
are
effective in
conditioning the input signal .
4. Set the Input Coupling switch to AC . The display will
remain on the screen , and the ac component of the signal
can be measured in the normal manner .
بال
POWER - UP
CHECKS
Noise may
be
coupled to
the A
and B
Trigger
circuits
along with the signal to be measured . Noise may originate
from the operating environment , the signal source , or by
improper
connections . If the noise
is of
sufficient amplitude ,
it can result in inaccurate measurements due to false trig
gering
.
The 2236
has a 20
MHz
Bandwidth
Limiter
that
is
helpful
in
removing
or
reducing
the
noise in
the A
and B
Trigger systems .
11
21
The Counter , Timer , and Multimeter ( CTM ) contains
Power
- Up
Checks that
are
performed each time
the
instru
ment is turned
on . These
checks
consists of ROM
checksum
, counter , and
DMM
in this order
. Each of
these
checks must pass before proceeding to the next check . If a
check fails ,
an error
message will
appear in the
readout ( see
Table 3-1 ) . Refer the error message to qualified service
personnel
.
Channel 1
volts
measurements
should be made
with the
signal fully
displayed
within the
graticule
area
through the
appropriate
use of
the
CH 1
VOLTS
/ DIV
switch
and
CH 1
VOLTS / DIV
Variable control . This
prevents
the
Channel 1
input circuit from
being
overdriven and
distorting the
voltage
measurements .
C
C
TABLE 3-1
Power -
Up Checks
U
STATUS
AND
ERROR
MESSAGES
Check
Error
Message
The Counter , Timer , and Multimeter ( CTM ) system will
display several types
of status and
error
messages on the
readout .
C
ROM Checksum
FAIL - ro
Counter FAIL - ctr
Control button
Error - When
the
buttons are in an ille
gal
mode , the
readout
will
display
“ Control
button
Er
ror " by
scrolling
it
across the
readout .
The
error
message
will
repeat
itself
until
a
correction
is
made
.
DMM
FAIL - d
Common
3-2

Tektronix 2236 Specifications

General

Brand	Tektronix
Model	2236
Category	Test Equipment
Language	English