Tektronix 2215, Instruction Manual

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ts
b v V tf c r D i o r L A Y. I
he A Disp signal becomes LU and
the B Disp signal applied to the base o f Q634 becomes HI.
Switching transistor Q634 is biased on, and the A Sweep
current is shunted to ground. The B Sweep current passes
to the in p u t summing ju n c tio n to be added to the h o ri­
zontal positioning current. The B Gain potentiom eter
(R682) is adjusted to provide the same gain fo r the B
Sweep signal as fo r the A Sweep signal.
A L T H O R IZ O N T A L D IS PLA Y . The A Disp and B Disp
signals are switched at the alternate sweep rate by the
A lternate Sweep Switching Logic c ircu it. When both
vertical channels are being viewed simultaneously, the
intensified traces o f both Channel 1 and Channel 2 are
firs t displayed, then both alternate B traces are displayed.
Horizontal Preamplifier
The sum o f the sweep and positioning current is applied
to the in p u t o f one side o f a diffe re n tia l a m p lifie r
composed o f Q730 and Q731. For all conditions o ther than
the X-Y Mode, X Y Switch transistor Q720 is biased on to
provide a ground reference at the other in p u t o f the d if­
ferential a m p lifie r (at the base o f Q731). The o u tp u t o f
the d iffe re n tia l am plifier, taken from the c o lle cto r o f Q731,
is am plified by Q736.
A feedback netw ork connected between the o u tp u t o f
Q736 and the base o f Q730 provides the c irc u itry required
fo r the X10 m agnification feature. In the unm agnified
mode, X 10 M agnifier switch S734 is closed and the feed­
back is provided by the paralleled com bination o f R732
and C732. Resistor R732 sets the unmagnified a m p lifie r
gain and C732 provides the HF compensation.
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