TM 11 6625-1668-12
(7) The Z MARKER facilitates making accurate measurements of the mark/space transitions of a bit. By
means of this switch it is possible to intensify the brightness of the leading and falling edges of the bit so that
measurements are made directly from the calibrated graticule. This is accomplished when the Z MARKER
switch is in the ON position. When a polar signal is displayed on the screen the positive bit is above the zero
axis and the negative bit is below the zero axis.
The brightness of all positive and negative transitions of the character will be intensified. On neutral, negative
or positive signals the baseline of the signal is the zero axis, and the intensification will take place above the
midpoint of the leading edge and from the midpoint to the baseline on the falling edge.
(8) The oscilloscope sweep circuit can be operated in an automatic mode, an internally triggered mode or
a free running mode.
(a) In the automatic mode the sweep is generated internally and is triggered by the analyzer speed and
code level settings.
(b) In the internally triggered mode the sweep is generated within the oscilloscope and triggered by a
signal from the analyzer, which produces one sweep for each character.
(c) In the free running mode the sweep is triggered through the use of periodically recurrent waveforms
generated within the oscilloscope. This mode provides a convenient means for viewing crossover patterns.
(d) In the internal mode the sweep release rate is controlled by the operator. In this mode, the
DISPLAY RELEASE RATE switch is set to tile VARIABLE position, causing the sweep to release once per
character. The repetition rate of the displayed character can be varied from 1 to 2 seconds by rotating the
DISPLAY RELEASE RATE control clockwise.
(e) In the free running and internal modes of operation the horizontal sweep is controlled by
the TIME MTLLISEC switch. This switch provides horizontal sweep from 50 microseconds to 500 milliseconds
in five steps. Each of these steps is adjustable by means of an overlapping vernier control.
(f) When a particular transition within a character, the sweep trigger Signal is applied one-half bit
preceding the transition to be measured. This function is controlled by the TRANSITION switch on the
analyzer. When a transition is selected, a blanking pulse will allow only the desired transition to be visible on
the screw.
e. Dolly, Test Set V 434/GGM-15(V). The V 434/GGM-16(V), hereafter referred to as the dolly (fig. 1-4),
is equipped with four swivel wheels or casters and is used to transport and position the test set at a convenient
level. The dolly is provided with a removable lower shelf for the storage of unused test equipment. A power
cable bracket is provided to store the power cables when not in use. For storage, the dolly is folded into a flat
package.
f. Cable Assembly, Special Purpose, Electrical CX-12105/U. The CX-12105/U, hereafter referred to as
power cable (fig. 1-6) is a three-wire cable, approximately 8 feet in length. One-cable connects each major
component to the ac power source.
g. Cable Assembly, Special Purpose, Electrical Branch. The CX-12024/GGM-16(V), hereafter referred to
as interface cable (fig. 1-6) is a special purpose cable used to interconnect the generator, analyzer, and
oscilloscope. The cable is approximately 2 feet long and has three connectors. Each connector is of a
different size and will only connect to the appropriate unit.
1-6. Technical Characteristics
The technical and physical characteristics for each major component of the test are listed below.
a. Generator Characteristics
Output message forms .................. Steady "MARK"
Steady "SPACE'
1:1 Reversals
Selected Character- 5, 6, 7 or 8-level start-stop or 8-bit synchronous.
Message--5-level 80 characters, may be strapped for an additional 48 field
programmable characters which are normally spaces. The standard 80 character
message is: CR CR LF LET TEST SP DE SP B/L B/L B/L B/L B/L B/L B/L SP SP SP
SP LET THE SP QUICK SP BROWN SP FOX SP JUMPS SP OVER SP THE SP
LAZY SP DOG FIG. SP 1234567890
1-9
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