Tektronix 516 series, Instruction Manual

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Operating Instructions — Type 5 1 6
Applications
The following paragraphs describe procedures for making
measurements of voltage, elapsed-time, and phase-shift with
the Type 516 Oscilloscope. No attempt has been made to
describe any but the most basic techniques. Familiarity with
the instrument will enable the operator to apply the essence
of these techniques to a wide variety of applications, de­
pending upon the problem at hand.
Voltage Measurements
To measure the ac component of a signal, proceed as
follows:
1. Display the waveform over as large a portion (verti­
cally) of the screen as possible by adjusting the appropriate
VOLTS/DIV. control.
2. With the aid of the graticule, measure the vertical
distance (in graticule divisions) between the two points on
the waveform at which the voltage measurement is desired.
Make sure the appropriate VARIABLE VOLTS/DIV. control
is in the CALIBRATED position. On small voltage measure­
ments, the width of the trace can make up an appreciable
part of the entire measurement. For this reason, it is im­
portant to take all readings in a given measurement from
the same side of the trace.
3. Multiply the distance between the two points by the
setting of the appropriate VOLTS/DIV. control and by the
attenuation factor, if any, of the probe. This is the voltage
between the two points of the waveform.
To measure the dc level at some point on a signal, pro­
ceed as follows:
1. Set the POLARITY switch of the channel to which the
signal is applied to the NORM. DC position.
2. Set the corresponding VOLTS/DIV. control such that
the expected voltage (at the oscilloscope input connector)
is not more than six times the setting of the control. Make
sure the VARIABLE VOLTS/DIV. control is in the CALIBRA­
TED position.
3. Set the oscilloscope controls to produce a free-running
trace.
4. Touch the oscilloscope probe tip to a ground point,
and with the appropriate VERTICAL POSITION control po­
sition the trace so that it lies along one of the horizontal
lines of the graticule. This line will be used as a ground
reference line; its position in any given case will depend
upon the polarity and amplitude of the input signal to be
measured. Do not adjust the VERTICAL POSITION control
after the reference line has been established.
5. Remove the probe tip from ground and connect it to
the signal source. Adjust the triggering controls for a stable
display.
6. Measure the distance, in graticule divisions, from the
ground reference line established in step 4 to the point at
which the dc voltage level is desired.
7. Multiply this distance by the setting of the appropriate
VOLTS/DIV. control and the attenuation factor, if any, of
the probe. This is the dc level of the point measured.
Time and Frequency Measurements
To measure the time interval between two points on a
waveform, proceed as follows:
1. Apply the signal to either of the Vertical Channels and
set the triggering controls for a stable display. Make sure
the VARIABLE TIME/DIV. control is in the CALIBRATED po­
sition.
2. Measure the horizontal distance, in graticule divisions,
between the two points whose interval you wish to find.
3. Multiply the distance measured by the setting of the
TIME/DIV. control. (If the HORIZ. DISPLAY switch is in the
MAG. position, use the blue numbers). This is the time in­
terval between the two points measured.
To determine the frequency of a recurrent waveform, sim­
ply take the reciprocal of the time interval between cor­
responding points on two consecutive cycles of the waveform.
Phase-Shift Measurements
A phase comparison of two signals of the same frequency
can be made by making use of the dual-trace feature of the
Type 516 Oscilloscope. To make this comparison, proceed
as follows:
1. Apply the two signals to the two input connectors and
set the MODE switch to the CHOPPED or ALTERNATE po­
sition. (In general, the CHOPPED position is more suitable
for low-frequency signals and the ALTERNATE position is
more suitable for high-frequency signals). Apply one of the
signals as an external trigger and set the triggering controls
for a stable presentation. Center both signals vertically on
the graticule.
2. Set the TRIGGERING LEVEL and HORIZONTAL PO­
SITION controls so that the leading waveform starts exactly
at the point where the horizontal centerline meets the verti­
cal line at the left-hand edge of the graticule.
3. Measure the distance, in graticule divisions, from the
left-hand edge of the graticule to the point where the other
waveform crosses the horizontal centerline. For the most ac­
curate measurement, use the fastest sweep/ rate possible.
Make sure that the VARIABLE TIME/DIV. control is in the
CALIBRATED position.
4. Multiply the distance measured in step 3 by the setting
of the TIME/DIV. control and divide by the period of one
cycle of the waveform. Multiply the
result by 360°. This is
the phase difference between the two signals.
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