Tektronix 7834

Operating Instructions-7834
2 . Do not apply large signals to the plug-in
inputs
.
A good
rule is to not apply a signal of more than about
eight times
the vertical deflection factor . For
example, with a vertical
deflection factor of 0 .5 volt/division,
the voltage applied to
that plug-in should not exceed
four volts . Larger voltages
may result in a distorted display .
3 . To
ensure the greatest dynamic range in the ADD mode,
set the position controls of the plug-in units to a setting
which would result in a mid-screen display if viewed
in the
LEFT or RIGHT positions of the VERTICAL MODE
switch .
4 . For similar response from each channel, use identical
plug-ins and set the plug-in units for the same type of input
or
coupling mode .
HORIZONTAL MODES . When either the A or B button
of the HORIZONTAL MODE switch is pressed, the signal
is
displayed at the sweep rate of the selected time-base
unit
. Set the applicable intensity control and trigger-source
switch for the desired display .
Alternate Mode . The ALT position of the HORIZONTAL
MODE switch provides crt sweeps derived alternately from
the two time-base units . Although the ALT horizontal
mode can be used at all sweep rates, the CHOP mode pro-
vides a more satisfactory display at sweep rates below about
20
milliseconds/division . At slower sweep rates, the
switching between the alternate-mode traces becomes
apparent and may interfere with correct analysis of the
display .
2- 1 8
NOTE
This instrument will not operate in the ALT
position of the HORIZONTAL MODE switch if
either horizontal plug-in compartment
is left
vacan t .
The A and
B INTENSITY controls allow individual
adjust-
ment of the traces produced by the time-base
units in the
A HORIZ and B HORIZ compartments .
Correct triggering
of both time-base units is essential
in obtaining the correct
display in the ALT horizontal mode
. If either of the time-
base units does not receive a
correct trigger, and therefore
does not
produce a sweep, the other unit cannot produce a
sweep
either . This means that one time-base unit cannot
begin its sweep until the previous unit has completed
its
entire display . This can be avoided if the time-base units
are set for auto-mode triggering (sweep free runs if not
correctly triggered) . See Trigger Source for operation of
the A and B TRIGGER SOURCE switches . Also, see
Vertical
Trace Separation for information on positioning
the B
HORIZ display when in the ALT dual-sweep mode
.
Chopped Mode .
When the CHOP button of the
HORIZONTAL MODE
switch
is
pressed, the display is
electronically switched
between the two time-base units at
about a 200 kilohertz rate . In general, the CHOP horizontal
mode provides the best display when either of
the time-base
units is set to a sweep rate slower than
about
20
milli-
seconds/division . It also provides the best display
when the
two time-base units are set to widely
differing sweep rates .
In the CHOP horizontal
mode, equal time segments are
displayed
from each of the time-base units . This provides a
display which does not change greatly, in intensity, as
the
sweep rate of either time-base unit is reduced (in contrast
to ALT horizontal mode operation where the slowest
trace
tends to be the brightest) .
The A and B INTENSITY controls allow individual
adjust-
ment of the intensity of the traces produced by the
time-
base units in the A HORIZ and B HORIZ compartments .
Triggering is not as critical in the CHOP horizontal
mode as
in ALT ; if one of the units is not triggered properly,
only
the trace from the untriggered time-base
unit is missing
from the display . The other trace is presented
in the normal
manner . See Trigger Source
and Vertical Trace Separation
for information on positioning
the trace produced by
the B HORIZ unit in
relation to the trace from the A
HORIZ unit .
Horizontal Selection . The Horizontal Selector switch
provides the means to override the HORIZONTAL
MODE
switch in selecting the horizontal compartment
for deflec-
tion . The Horizontal Selector switch has
three positions
(Normal, A, and B) . In Normal
the operation of the
HORIZONTAL
MODE switch is unchanged . In A or B the
plug-in compartment selected by the Horizontal Selector
switch provides the signal for horizontal deflection . The
plug-in compartment selected by the HORIZONTAL
MODE switch provides the other control signals,
such as
unblanking, storage control, etc .
The Horizontal Selector switch
provides a convenient
method of storing X-Y
displays using the FAST BISTABLE
or FAST
VAR PERSIST storage modes . These storage
modes require
control signals, provided by a time-base unit
or an external input signal
(see
REMOTE
STORAGE GATE
INPUT), to develop a stored
display
.
For X-Y storage, the
Horizontal Selector switch can be set to display the signal
from
an amplifier unit
installed in one of the horizontal
compartments . The HORIZONTAL MODE switch can
select the other plug-in compartment, with a time-base unit
installed, allowing the storage circuitry and crt unblanking
to be controlled
by the time-base unit while the horizontal
deflection is
provided by the amplifier unit .