Tektronix 455 User Manual

Instrument Options—455/A2/B2
3. Set the X I0 MAG button to the in position and horizon
tally position the display desired. This provides sufficient
resolution to identify the field.
horizontal sync pulse. The Field 1 picture starts with a full
line of video.
4. If the displayed field is not the one desired, momentarily
switch the A SLOPE to the opposite polarity several times
until the desired field is displayed.
Field 1 lines are numbered 1—263, starting at the leading
edge of the first equalizing pulse. The first regular horizontal
sync pulse after the second equalizing interval is the start of
line 10.
5. Horizontally position the display until the desired line Field 2 starts with an equalizing pulse a half-line interval
becomes visible. from the preceding horizontal sync pulse. The Field 2
picture starts with a half line of video.
6. Adjust the DELAY TIME POS control to move the in
tensified zone to the desired line. It may be desirable to set
the X I0 MAG button to the unmagnified (button out)
position to locate the intensified zone. With the X I0 MAG
button out, use the DELAY TIME POS control to move the
intensified zone to the horizontal center of the crt. When
the X I0 MAG button is again set to the in position, the
intensified zone will remain in the viewing area.
7. When the desired line is intensified, set the HORIZ
DISPLAY switch to B DLY'D. This displays the desired
line.
Field 2 lines are number 1—262, starting at the leading edge
of the second equalizing pulse. After the second equalizing
interval, the first full line is line 9.
CCIR System B (including PAL)
In most 625-line, 50 Hz field-rate systems, identification of
parts of the picture relies primarily on continuous line
numbering rather than on field-and-line identification, except
for PAL systems.
8. If there is too much jitter, set the B SOURCE switch to
the TV LINE position and adjust the B LEVEL control for
a stable display.
Two Frame A Sweep Cycle
If PAL burst blanking is to be checked, use the same proce
dure as for a one-frame A Sweep cycle with the following
exceptions: 1
1. Set the A TIM E/DIV switch to 5 ms instead of 2 ms.
The CCIR frame starts with the first (wide) vertical sync
pulse following a field which ends with a half-line of video.
The first line after the second equalizing interval is line 6;
the first picture line is line 23 (half-line of video). The first
field of the frame contains lines 1 through the first half of
line 313, the picture ending with a full line of video (line
310).
The second field of the frame commences with the leading
edge of the first (wide) vertical sync pulse (middle of "line"
313), and runs through line 625 (end of equalizing interval).
The first full line after the equalizing interval is line 318;
the picture starts on line 336 (full line).
2. Adjust the A TRIGGER HOLDOFF control for a display The first field is referred to as "odd", the second field as
locked on a given field (increase hold off time by 1 field). "even". Note that the identification systems for System M
and System B are opposite. 3
3. Momentarily switch the A SLOPE switch to the opposite
polarity several times until the desired field is displayed in |n the four-field PAL sequence with Bruch Sequence Color-
the desired position. burst blanking, the fields are identified as follows:
IDENTIFYING FIELDS, FRAMES, AND LINES
NTSC (CCIR System M)
Field 1 is defined as the field whose first equalizing pulse is
one full horizontal interval (63.5 /us) from the preceding
Field 1: Field which follows a field ending in a half-line of
video, and which preceding field has color burst on
the last full line. Field 1 lines are 1 through 312
and half of line 313. Color burst starts on line 7
of Field 1; a half-line of video appears on line 23.
Option 5 Page 4
REV. A, OCT 1975

Tektronix 455 Specifications

General

Brand	Tektronix
Model	455
Category	Test Equipment
Language	English