Vert Trace Separation (B) - Tektronix 7140 Instruction Manual

DISPLAY B
COMMAND
B MODE (HORIZ)
CONTROL
ALT MODE (VERT)
R4438
DELAY MODE
04438
R4431~
CR4434
04442
04448
VERT TRACE
SEPARATION (B)
xxJ
04456
TRACE
SEPARATION
I I
ALL OTHER COMBINATIONS NO OUTPUT
~ = HAS NO EFFECT IN THIS CASE
Figure 3-7 . (A) Logic diagram of Trace Separation stage; (B) Table of input/output combinations .
Theory of Operation-7104
(1195-22) 2314-6
since the average screen current associated with these Without a vertical plug-in unit in a horizontal
bright spots can be large enough to enable the intensity compartment; diodes CR4487 and CR4495 do not
limiter. conduct. 04488 acts as an emitter follower . Resistors
R4486 and R4487 perform a do level shift approximately
By triggering the time-base unit with the Y-Axis signal,
equal to the emitter-base drop of 04488. 04492 is
the duty cycle of the Z-Axis can be controlled with the turned off, so the voltage at the collector of 04492 is a
time-base unit time/division control. With the duplicate of the Display B Command. If diode CR4487 is
HORIZONTAL MODE switch set to ALT an X-Y display
connected to ground by an amplifier unit in the B HORIZ
alternating with a Y-T display is obtained . The Z-Axis for compartment the Display B Command is not applied to
both displays is on only during the time that is displayed
the base of 04488 and the signal at the collector of
in the Y-T display. This is a visible aid for optimum
04492 is LO . In this condition the Z-Axis logic IC selects
control of the Z-Axis duty cycle of X-Y displays . For
the A INTENSITY input only, independent of other control
certain applications of X-Y display, it may be desirable
inputs. If diode CR4495 is connected to ground by an
that control of the Z-Axis is determined by the selection
amplifier unit installed in the A HORIZ compartment,
of the HORIZONTAL MODE switch . A slide switch located
04492 is saturated. The emitter of 04488 is held at a HI
on the Logic board selects how the Z-Axis is controlled
level, so even when the Display B Command is HI, 04488
during X-Y displays . Normally the switch should be in the
does not conduct. The Z-Axis logic IC selects the B
IN position such that for X-Y displays the Z-Axis is Intensity input when the signal at the collector of 04492
controlled by a time-base unit .
is HI, regardless of other control inputs .
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