Operating instructions

The following
information provides a description of electrical
operation of the Option 2 Time Base X-Y function and is
in-
tended to supplement
the circuit operation description for the
standard instrument as given in Section 3 of this manual
.
The
Option 2
circuitry is described with reference to the schematic
diagrams in the Diagrams section at the rear of this manual . Re-
fer to these
schematic
diagrams
throughout the following circuit
operation description for specific electrical values and rela-
tionships .
The following discussion is
provided to aid in understanding the overall
concept of the additional circuitry unique to the Op-
tion 2 Time-Base
unit before the circuits are described in detail .
The Option 2 instrument has an additional
circuit board (X-Y Switch Board) that is mounted
to the rear of the instrument
Interface Board . This circuit board
contains the DISPLAY MODE switch, and the
logic circuitry to control the sweep dis-
play, readout display, and
X-Y functions unique to the Option 2 instrument
. The additional circuitry provides switching of
the trigger signal
input path to the sweep signal output path
for the X-Y display mode of operation . The circuit board
also
contains logic
circuitry to disable the sweep and readout functions, maintain an
unblanked crt display, and switch
a compen-
sation network
into the mainframe horizontal signal path (option 2
mainframes only) for X-Y compensation . A schematic of
this circuit, with all
of
the
X-Y Switch Board functions labeled, is
shown on diagram 7 in the Diagrams section of this
manual .
Time Base Mode
X-Y
SWITCHING O7
The
DISPLAY MODE switches S935-S936 select either the
normal sweep
and
internal triggering signal paths for time
base
operation, or select X-Y operation with the instrument
trigger input path connected to the sweep output path
for
trigger path continuity only . Refer to diagram 7
through-
out the following discussion of the time base
and X-Y dis-
play modes .
When the
DISPLAY MODE button is pressed and
latched
to
the IN : TIME BASE position, all time base electrical
operation and functions are the same as described
for the
standard instrument (see Section 3-Theory of
Operation) .
The Option 2 instrument, however,
has the internal trigger
and sweep signal paths
routed through the X-Y Switch Board
.
The following description explains the signal paths in
more
detail .
The internal trigger signal from
the mainframe is routed to
the X-Y Switch Board, passes
through DISPLAY MODE
switch contacts S935A and D,
then proceeds to the Inter-
nal Trigger Amplifier
stage, U35 (diagram 2) . The sweep
output signal from the
Output Preamplifier (diagram 4-
Sweep), is routed to
the X-Y Switch Board, passes through
DISPLAY MODE switch
contacts S936A and D, then pro-
ceeds from the time-base
unit to the mainframe horizon-
tal deflection system .
THEORY OF
OPERATION
BASIC DESCRIPTION
X-Y Mode
Option 2-71380
When the DISPLAY MODE button is pressed
and released
to
the OUT : X-Y position, the signal paths through
the
X-Y
Switch Board are altered as explained in the
follow-
ing
discussion .
The internal trigger signal from the mainframe is
disconnect-
ed
from the usual trigger path and connected to the
instru-
ment
sweep output path through DISPLAY MODE
switch
contacts S935A and D-S936A and D . An X-axis
signal can
now be connected through any vertical unit
and coupled
through the mainframe trigger path and
the Option 2 Time
Base to provide the horizontal deflection
for the mainframe
display . The trigger path to Internal
Trigger Amplifier stage
U35, and the sweep output path
from the Output Preampli-
fier (sweep) are open
circuits in this mode because those
functions are not used .
In the X-Y mode of
operation, logic circuitry on the X-Y
Switch Board causes
the sweep, readout display, and nor-
mal crt display
Z-axis unblanking functions to be disabled .
The following information describes the logic functions
controlling the instrument for the input and output logic
lines labeled on diagram 7 .
SWEEP LOCKOUT . The Sweep Lockout
current level at
interface connector pin B8 is H I (+5-volt supply
through
DISPLAY
MODE switch contact S936B and resistor R961) .
Option
2-Page 5