Tektronix 47E5A

Use the DELAY TIME POSITION dial to move the
intensified zone to the CH 1 pulse. Set the HORIZ
DISPLAY switch to 8 DLY'D. Readjust the DELAY TIME
POSITION dial to move the CH 1 pulse or rising portion to
some vertical reference line (see Fig. 278). Note the
DELAY TIME POSITION dial setting.
Use the DELA Y TI ME POS ITION dial to move the CH 2
pulse or rising portion to the same reference line. Again
note the DELAY TIME POSITION dial setting .
Substitute the DELAY TIME POSITION dial settings in
the time difference formula to find the time difference .
EXAMPLE:
The A TIME / DIV switch is set to 50 ps and
the 8 TIME / DIV switch is set to 2 ps . Use the DELAY TIME
POSITION dial to move the CH 1 pulse to the reference
line. The DELAY TIME POSITION dial setting is 2.60.
Use the
DELAY TIME POSITION dial to move the CH 2
pulse to the reference line . The DELAY TIME POSITION
dial setting is 7.10.
To find the time difference use the formula :
[
second first] delay time
Time
= dial dial X (A TIME/DIV
difference
setting setting setting)
Substituting the given val ues:
Time Difference = (7.10 - '2.60) X 50 ps = 225 ps
RISETIME (BASIC 475A)
R isetime measu rements use the same methods as time-
duration measurements, except the measurements are
made between the 10% and 90% points of the waveform .
Falltime is measured between the 90% and 10% points on
the trailing edge of the waveform.
Use a sweep speed setting that displays several cycles
or events (if possible) and be sure the VAR TIME / DIV
control is in the calibrated detent. Set the VOL TS/ DIV
switch and the VAR control (or signal amplitude) for
exactly a five-division display. Set vertical positioning so
the display bottom touches the 0% graticule line and the
display top touches the 100% graticule line (see Fig. 28).
Set the A
TIME / DIV switch for a single-event di splay
with the risetime spread horizontally as much as possible .
Horizontally position the display so the 10% point of the
waveform intersects the second vertical graticule line (see
Fig. 28) . Set
the 8 TIME / DIV switch to the fastest sweep
speed
that provides a usable (visible) intensified zone .
Use the DELAY TIME POSITION dial to move the start
of the intensified zone (left-hand edge) to just touch the
intersection of the signal and the 10% graticule line (see
52
475A1DM44 Operators
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