Instrument Familiarization; Vertical Channel Selection; Vertical Deflection Factor; Trigger Source - Tektronix 214 Instruction Manual

214 OPERATORS
SN B300000 & ABOVE
INSTRUMENT FAMILIARIZATION
VERTICAL CHANNEL SELECTION
Either of the input channels can be used for single-trace
displays. Select the desired channel via the VERT MODE
switch and apply the signal to the appropriate probe.
Controls for each channel are color-coded to the tip of the
appropriate probe . For dual-trace operation , set the VERT
MODE switch to BOTH and connect the signals to both
input probes and adjust the channel POS controls to display
the signals. In SINGLE SWP mode with the VERT MODE
switch set to BOTH , only one channel will be displayed for
each RESET actuation .
VERTICAL DEFLECTION FACTOR
The amount of vertical deflection produced by a signal
applied to one of the vertical channels is determined by the
signal amplitude , the attenuation factor, and the setting of
the appropriate VOLTS/DIV switch and VAR control. The
calibrated deflection factors indicated by the VOLTS/DIV
switch apply only when the VAR VOLTS/DIV control is set
to the CAL detent .
The VAR VOLTS/DIV control provides continuously
variable (uncalibrated ) vertical deflecton factors between the
calibrated setting of the VOLTS/DIV switch . The VAR
VOLTS/DIV control extends
the maximum vertical
deflection factor to at least 125 V/div ( in the 50 V position ).
8
TRIGGER SOURCE
The TRIG SOURCE switch allows for selectivity in
determining the source of the signal used to trigger the
sweep . For most applications , the sweep can be triggered
internally. In the COMP position , the trigger signal is
obtained from the the vertical deflection system after the
vertical switching has occurred . Therefore , in the dual-trace
mode of operation , the display will be triggered on the
vertical chopping signal and not necessarily on the selected
slope of the LEVEL/SLOPE control . In this position , the 214
will trigger on at least 0.2 division of the applied signal,
within the bandwidth limits of the instrument .
In the CH 2 position of the SOURCE switch , the trigger
signal is again obtained internally , but is selected before the
vertical switching and only from
CH 2 of the vertical
deflection system . The display will trigger on at least 0.2
division of the applied capacitively coupled signal. In the
dual-trace mode , if the displayed signals are time-related ,
both channels can be triggered on the selected slope with
the TRIG SOURCE switch in the CH 2 position .
The external trigger signal is useful when signal tracing in
amplifiers , phase-shift networks , wave-shaping circuits , etc.
The signal from a single point in the circuit under test can be
connected to the EXT TRIG banana jack . Then the sweep is
triggered by the same signal at all times to allow amplitude ,
time relationship , waveshape changes , or signals at various
points in the circuit to be examined without resetting the
trigger controls.
TRIGGER SLOPE
The LEVEL/SLOPE control determines whether the
trigger circuit responds on the positive-going or negative
going portion of the trigger signal . When the indicator dot is
to the left of center , the trigger circuit responds on the
positive-going portion of the triggering waveform (notice the
positive-going waveform to the left of the control). To the
right of center, the trigger circuit responds to the negative
going portion of the triggering waveform
(notice the
negative-going waveform to the right of the control). Since
the instrument does not have an internal delay line , the
display might not start on the selected slope , particularly
when the displayed waveforms have a high repetition rate.
When several cycles of a signal appear in the display, the
selection of the trigger slope is often unimportant. However,
if only a certain portion of a cycle is to be displayed , the
correct setting of the LEVEL/SLOPE control is important to
provide a display which starts on the desired slope of the
input signal.
TRIGGER LEVEL
In
addition to selecting the trigger slope,
the
LEVEL/SLOPE control determines the voltage level of the
trigger signal at which
the display is triggered . The
horizontal line marked on the waveforms to the left and right
of the LEVEL/SLOPE control represents the zero-volt level
of the trigger signal . As the LEVEL/SLOPE control is
rotated away from this line , the displayed waveforms start
at a point corresponding to the position of the indicator dot
on the associated slope waveform . For example , if the
LEVEL/SLOPE control is turned clockwise from the line on
the positive-going slope, the displayed waveform starts at a
more positive level.
REV MAR 1985