Tektronix 7834 - X-Y Operation; Raster Displays

can be applied to a vertical amplifier and amplified before it
is internally routed by the trigger source switches to the
counter trigger circuit . This allows the unit
to
be used on
signals too small
to
trigger other counters .
READOUT ACCESS PLUG-IN UNIT . The
7M13 READ-
OUT plug-in unit provides font-panel keyboard operation
for convenient access to the crt readout characters . This
allows information, such as dates
and identifying
nomen-
clature,
to
be displayed
on the crt with the normal crt
display . This capability is particularly useful when making
photographs .
TRANSISTOR CURVE-TRACER PLUG-IN UNITS . The
7000-Series transistor curve-tracer plug-in checks small-
signal
transistors and diodes by producing a display showing
the basic characteristic
curves for the device being tested .
Stepped sweep signals from
an internal power supply are
applied to the device under test . The resulting output
signals are, in turn, applied
to the horizontal and vertical
deflection systems of the oscilloscope
to plot a family of
characteristic curves . This plot can be used
to
check
for
damaged transistors and diodes, or to select for special or
matched characteristics and to calculate gain, leakage,
breakdown voltage, etc .
SPECTRUM ANALYZER PLUG-IN UNITS
.
The
7000-
Series spectrum analyzer plug-in units display applied-signal
amplitudes dispersed over portions of the rf spectrum .
Absolute signal energy is plotted on the vertical axis against
frequency on the horizontal axis . Applications include
waveform and distortion analysis, EMC and random noise
measurements, filter design, spectrum surveillance, etc .
X-Y Operation
In
some applications, it is desirable to display one signal
versus another (X-Y)
rather than against time (internal
sweep) .
The flexibility of the amplifier plug-in units avail-
able
for use with the 7834 provide the means of applying
external signals to the horizontal-deflection system .
Installation of a 7A-Series amplifier plug-in unit in one
of
the horizontal and one of the vertical compartments
provides X-Y operation . For further information, refer to
the horizontal
specifications in this manual and to the
individual instruction manuals for the amplifier units .
Raster Displays
Operating Instructions--7834
Some of the 7B-Series time-base units can be operated as
amplifiers
in
addition to their normal uses as time-base
generators . This feature allows an external signal to provide
the horizontal deflection to the crt . For most of the time-
base units with the amplifier function, the
X
(horizontal)
deflection signal
can be connected either to an external
input connector
on
the time-base unit, or
it
can be routed
to the time-base unit through the internal triggering system
(see time-base instruction manual for details) . If the latter
method is used, the A and B TRIG SOURCE switches must
be set so
that
the
X (horizontal) deflection
signal
is
obtained
from
one
of
the
vertical
amplifier
units
and Y
(vertical) deflection signal is obtained from the other
vertical unit . The attenuator switch
on
the amplifier unit
can provide the horizontal
with a
preconditioned signal,
compatible with the horizontal deflection factor . Also,
plug-in units need not be moved from one compartment
to
another
to change from X-Y operation to other modes of
operation .
A raster-type display can be used effectively
to increase the
apparent sweep length . For this type of display, the trace is
deflected
both vertically and horizontally by sawtooth
signals . This is
accomplished in the 7834 by installing a
7B-Series time-base
unit in one of the vertical plug-in
compartments . Normally,
the time-base unit in the vertical
compartment should be set at a slower sweep
rate than
the
time-base unit in the horizontal compartment ; the number
of horizontal traces in the raster depends upon the ratio
between the two sweep rates .
Information
can be displayed on the raster using several
different
methods . In the ADD position of the VERTICAL
MODE switch, the signal from an amplifier unit can be
algebraically added to the vertical waveform . With this
method, the vertical signal amplitude on the crt should not
exceed
the distance between the horizontal lines of the
raster .
Another method of displaying information on the
raster is
to
use the
Z-AXIS INPUT to provide intensity
modulation for the
display . This type of raster display
could
be used to provide a television-type display .
Complete information on operation using the Z-axis feature
is given under Intensity Modulation .
To provide a stable raster display,
both
time-base units
must be correctly triggered .
Internal triggering is not pro-
vided for the time-base units
when they are in the vertical
compartments ; external triggering
must be used . Also,
blanking is not provided from the time-base units when
they are installed in a vertical compartment .