Table of Contents
Advertisement
Sect, n Page 3
Select the two centimeter portion to be magnified
with the H RIZ NTAL P SITI N control.
Trigger Level - Normally, a trace will be displayed
in the absence of a signal, since the oscilloscope is
triggered automatically. However, you may select
the point of triggering and stop the AUT MATIC
triggering with the TRIGGER LEVEL control. Move
this front panel screwdriver control clockwise away
from the AUT MATIC switch position (extreme coun
terclockwise) only for special triggering. In the AU
T MATIC position the sweep is self-triggered in the
absence of a triggering signal. When a signal is fed
in, the signal controls the triggering action. In the
AUT MATIC position the trigger circuit is adjusted
to optimum setting to trigger on the majority of wave
forms and at a zero trigger level. As you .rotate the
control clockwise from the AUT MATIC switch po
sition the automatic sweep feature will stop. Further
rotation erf this control permits you to adjust the trig
gering level of the pattern, within limits.
2-6
HORIZONTAL AMPLIFIER
The SWEEP TIME - H R. SENS, switch also con -
trols the sensitivity of the horizontal amplifier when
it is used with an external input. The three sensiti
vity ranges of the horizontal amplifier are . 1, 1, and
10 V LTS/CM. The sensitivity of the amplifier may
be increased to 100 V LTS/CM by means of the VER
NIER control.
Even though the circuitry of the vertical and horizon
tal amplifiers is not identical, the bandshapes and
phase characteristics are identical, at least to well
above 100 kc. As a result the instrument is rated as
having not more than 2° differential phase shifts be
low 100 kc and is thus well suited to phase difference
measurements. In fact, because the horizontal ampli
fier has basically an even wider response than the
vertical, an adjustment (C107, Phase Adjustment) is
provided in the horizontal amplifier so that phase
differences can, if desired, be minimized at indivi
dual frequencies above 100 kc. The adjustment con
sists of a small variable capacitor which acts to set
the first high-frequency corner of the horizontal am
plifier for optimum agreement with that of the verti
cal. At the factory this adjustment is set for opti
mum agreement at 100 kc.
2-7
CALIBRATOR
An internal square-wave calibrator with an accuracy
of ±2% and a nominal frequency of 400 cps is provided
for checking amplifier calibration accuracy. The cal
ibrator is connected internally to the input of the ver
tical amplifier when the VERT. SENSITIVITY switch
is placed in the CAL. position. When in the CAL. po
sition a 60 millivolt square wave is fed into the ver
tical amplifier input for calibration purposes. Be
cause of the inherent stability and medium sensitivi
ty of the horizontal amplifier, no provision is made
for internal connection between that amplifier and the
calibrator. Horizontal amplifier calibration can be
checked easily, however, since an external signal can
be measured on the vertical amplifier and then applied
to the horizontal as a check. Little adjustment of the
horizontal amplifier is necessary.
In either automatic or trigger operation the sweep
circuits wiU trigger from signals over a range from
600 kc to below 5 cycles (50 cps for automatic opera
tion). Between 10 cps (50 cps for automatic) and 200
kc the minimum deflection needed for triggering from
displayed waveforms is 0. 5 cm peak-to-peak. Be
yond this range an increase in this minimum will
occur, but at 600 kc, for example, triggering will
usually occur on waveforms that give 2 cm deflec
tion. For external trigger signals a minimum am
plitude of 2-1/2 volts peak-to-peak is required for
the minimum frequency to 200 kc ranges.
2-8
EXTERNAL
YNCHRONIZATION CONTROL
Switch the SYNCHR NIZATI N control to the EX
TERNAL position. Feed in the external synchro
nization signal (2. 5 volts or more peak-to-peak)
into the horizontal input terminals at the lower right
corner of the front panel. The external synchro
nization signal is always ac coupled and synchro
nizes on the negative slope of the signal. When using
the trigger level control the trace will trigger on the
negative slope of signals within the range of +10 and
-10 volts, approximately (see Figure 2-2).
Figure
2-2.
Triggering
2-9
AC OR DC COUPLING
AC coupling permits high gain to be employed with
Advertisement
Table of Contents
