Tektronix 323, Инструкция по эксплуатации

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Operating Instructions— Type 323
shortest possible probe ground lead and connect it to a
ground point as near to the signal source as possible. See
Fig. 2-12. If ringing persists, connect the Oscilloscope ground
jack to the equipment under test, using the shortest possible
lead. Then disconnect the external power leads and operate
the Oscilloscope on its internal battery power.
Loading. Use a 10X probe whenever possible. It pro­
vides more accurate waveform observation by reducing the
loading effect on the signal source. Deflection factors in­
dicated by the VOLTS/DIV switch must be multiplied by 10
when a 10X probe is in use.
Phase and Polarity Relationships. When internal trig­
gering is used, the signal slope displayed at the beginning
of the sweep is dependent upon the trigger slope selected
by the operator. If a comparison of phase or polarity is
required, use external triggering and the same trigger source
for the entire sequence of phase or polarity comparisons.
The examples in Fig. 2-13(B) use + internal triggering and
give the indication that the positive spike is coincident with
the rising portion of the square wave. The examples given in
Fig. 2-13(A) both use the same + external trigger source
and show that the square wave actually goes negative
at the time the positive spike occurs.
External triggering is extremely useful in measuring phase
difference between signals. The circuit in Fig. 2-14(A) is
used to demonstrate this feature.
Connect the reference waveform to the external trigger­
ing and the vertical input connectors. Select negative slope
external triggering and adjust the triggering and horizontal
(A ) Ground loop completed through pow er supply common
ground.
(B) Probe ground lead connected to equipm ent ground.
Fig. 2 -1 2 . Reducing rin g in g caused b y ground loop.
TRIGGER OUTPUT
— C UTPl T
(A ) Synchronous signals observed w ith - f external trig g e rin g show true tim e rela tionsh ip.
1
1
•
i :
-V-*
S
TRIGGER OUTPUT
( B ) Synchronous signals observod w ith +
— O UTPl T
in te rn a l trig g e rin g show incorrect time relationship.
Fig. 2 -1 3 . Inip oitance o f exte rna l trig g e rin g fo r phase o r p o la rity com parison. (Signals supplied by Tektronix Type 106 Square-W ave Gen­
e rator.)
2-17