Tektronix 2221 User Manual

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Controls , Connectors , and Indicators - 2221 Operators
30 EXT COUPLING Switch - Determines the method of
coupling the
external signal
applied to the EXT
INPUT connector to the input of the Trigger circuit .
In STORE mode , pressing the SGL SWP button to
arm the trigger circuitry does not immediately turn
on the READY LED . The pretrigger portion of the
acquisition
memory starts
filling after
the SGL
SWP
button is
pressed in , and the
READY
LED
is turned
on when the filling is completed . The storage acquisi
tion system is
then ready
to accept a
triggering
event . After an acquisition is completed , the READY
LED is turned off .
AC - Input signal is capacitively coupled , and the
dc
component is
blocked
.
DC - All
frequency
components
of the
external
signal
are
coupled to
the Trigger
circuit .
25 )
TRIGGER LEVEL
Control
- Selects
the
amplitude
point on the trigger signal that produces triggering .
The trigger point for STORE mode is identified by a
T on the acquired waveform .
DC - 10 - Attenuates the external signal by a fac
tor of ten before application to the Trigger circuit .
As with
DC
COUPLING
,
all
frequency
com
ponents of the input signal are passed .
26 ) HF
REJECT
-
Rejects (
attenuates )
the
high
frequency components ( above 40 kHz ) of the trigger
signal when
the control is in
the ON
position
.
31 EXT INPUT ConnectorProvides for connection of
external signals to the Trigger circuit .
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27 )
TRIGGER
SLOPE Switch -
Selects either the
posi
tive or negative slope of the trigger signal to start
the NON - STORE Sweep or to reference the next
STORE
mode
acquisition
cycle .
28 INT Switch - Determines the source of the internal
trigger signal
for the Trigger
Generator circuits
.
32 ) VAR HOLDOFF Control Adjusts the NON - STORE
Variable Holdoff time . NON - STORE Variable Holdoff
starts at the end of the Sweep . STORE mode
Holdoff starts at the end of the acquisition cycle and
ends after the waveform data has been transferred
from
acquisition to display
memory
and
the pre
trigger portion of the acquisition memory has been
filled . After STORE mode Hoidoff ends , the next
acquisition can be triggered after the next ( or
current
, if one
is in
progress ) NON -
STORE
Variable
Hoidoff
ends
.
STORE
mode Holdoff may
be
many
times the length of the Sweep time so that several
NON -
STORE
Holdoffs may have
occurred
during
STORE Hoidoff time . This ensures that STORE
mode triggering is
controllable
by the VAR
HOLD
OFF control and will be stable if the NON - STORE
display
is
stable .
CH 1 - Trigger
signal is
obtained from the CH
1
input .
VERT MODE
- Trigger
signals are
automatically
obtained alternately from the CH 1 and CH 2
input signals in
ALT
VERTICAL MODE . In
the
CHOP or
ADD
VERTICAL
modes , the
trigger sig
nal source is the sum of the CH 1 and CH 2 input
signals .
STORAGE CONTROLS
CH 2 - Trigger
signal is
obtained from the CH
2
input . The CH 2 INVERT switch also inverts the
polarity of the internal CH 2 trigger signal when
the CH 2 display is inverted ,
See Figure 3-5 for the location of items 33 through 37 .
29 )
SOURCE
Switch -
Determines if the
source of the
Trigger signal is internal , external , or from line .
33 ) STORE / NON - STORE Switch -- Selects either the
NON -
STORE
or the
STORE
waveforms for
display
.
The STORE
acquisition
system
is turned off
while
NON - ST RE
selected so that
the last
acquired
STORE
waveform
remains in
memory .
Selects
NON -
STORE when out
and
STORE when
pressed
in .
INT -
Routes the
internal trigger signal
selected
by the INT switch to the Trigger circuit .
LINE
-
Routes a
sample of
the
ac
power
line
sig
nal to the
Trigger
circuit
.
EXT
-
Routes an
external
signal
applied to
the
EXT
INPUT connector to
the
Trigger circuit .
34 )
ACQUISITION
Controls.Determine the
method of
acquiring and displaying the acquired STORE
waveform ,
3-10
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Tektronix 2221 Specifications

General

Brand	Tektronix
Model	2221
Category	Test Equipment
Language	English