Tektronix 2221 - Page 36

C
Controls
,
Connectors
, and
Indicators
-
2221
Operators
1X PROBE - Front - panel marking that indicates
the deflection factor set by the VOLTS / DIV switch
when a 1x probe or a coaxial cable is attached to
the
channel input
connector
.
age display ( does
not ground
the input signal
) . In
STORE mode , the ground reference is acquired
and displayed
in the first sample
location
of
the
acquisition waveform display . When GND input
coupling is selected , a ground symbol is displayed
in the associated VOLTS / DIV readout .
10X
PROBE_Front - panel
marking that
indicates
the deflection factor set by the VOLTS / DIV switch
when a properly coded 10X probe is attached to
the
channel input
connector
.
C
DC - All frequency components of the input signal
are coupled
to the
vertical
deflection and signal
acquisition systems . When DC input coupling is
selected , no additional indicators are displayed
with the associated VOLTS / DIV readout .
If properly coded probes ( 1X , 10X , or 100X ; see
Table 3-1 )
are
connected to a
channel
input
connec
tor , the crt VOLTS / DIV readout will reflect the
correct
deflection
factor of
the display .
Table 3-1
13 ) CH 1 OR X and CH 2 OR Y Input Connectors
Provide for application of signals to the inputs of the
deflection
systems
and
the
storage
acquisition
system
.
Probe
Coding
Probe
Coding
Resistance
1X
Infinite
다 .
10X
11 ΚΩ + 10 %
Coding - ring contacts on each of the input connec
tors are used to automatically switch the scale factor
displayed by the crt readout when a properly coded
probe is attached to the input connector . Displayed
STORE mode waveforms are reformatted to main
tain the correct deflection as indicated by the
VOLTS / DIV readout on the affected channel ( s ) . In
X - Y mode , the
signal
connected to the CH
1 OR X
input controls the horizontal deflection , and the sig .
nal connected to the CH 2 OR Y input controls the
vertical deflection .
100X
5.6 2 -10 % to 6.2 k.2 + 10 %
IDENTIFY
On or none of the above
U
11
Variable
VOLTS
/ DIV
Controls
—
Provide
continu
ously variable deflection factors between calibrated
positions
of
the
VOLTS /
DIV
controls .
The
VOLTS
/
DIV
sensitivity may
be
reduced by up to
at
least 2.5 times
at the fully
counterclockwise
rotation
of the
variable
knob
. A
detent
position
at
fully
clock
wise rotation indicates the calibrated VOLTS / DIV
position of the variable knob . The uncalibrated condi
tion is
indicated by
a
greater -
than
symbol ( > )
in
front of the
affected
VOLTS /
DIV
readout
.
14 ) CH 2
INVERT
Switch
-
Inverts
the
Channel
2
display
and STORE
mode
Channel
2
acquisition signal when
pressed in . An invert symbol ( 1 ) is displayed with
the CH 2 VOLTS / DIV readout when CH 2 is
inverted .
With CH 2
inverted , the
oscilloscope
may
be operated as a differential amplifier when the
BOTH - ADD VERTICAL MODE is selected .
12 AC - GND - DC ( Input Coupling ) Switches -- Select the
method of coupling the input signal from the CH 1
and CH 2
vertical
input
connectors to the
vertical
amplifiers and the
storage
acquisition
system
.
15 ) VERTICAL MODE Switches Select the mode of
operation of the vertical channels . There are two
three - position switches and one two - position switch
that determine display and acquisition modes and
one two - position push - button switch that controls
the NON -
STORE bandwidth .
AC -
Capacitively
couples the input
signal to the
vertical
deflection and
signal
acquisition
systems .
The de component of the input signal is blocked .
The
lower -3 dB
bandpass is
10 Hz
or
less
.
Selection
of
AC input
coupling
is
indicated
in the
readout
by
a tilde
symbol
( ) over
the V on
the
associated
channel's
VOLTS
/ DIV
readout
.
CH 1 -
Selects only the
Channel 1
input
signal for
acquisition or
display .
GND -
Grounds
the
input of the
vertical
deflection
channel ; provides a zero ( ground ) reference volt
BOTH -
Selects
a
combination of
Channel
1 and
Channel 2
input
signals for
acquisition or
display
( CH 1 - BOTH - CH 2 switch must be in the BOTH
position for ADD , ALT , and CHOP operation ) .
3-4