Tv Line Signal; Tv Field Signal - Tektronix 2235 Instruction Manual

Operating Procedures—2235 Operators
1. Set the time duration of the reference signal to an
exact number of horizontal divisions by adjusting the
A SEC/DIV switch and the SEC/DIV Variable control.
2. Establish a horizontal conversion factor, using the
following formula (reference signal time duration must be
known):
Horizontal
Conversion
Factor
reference signal time
duration (seconds)
horizontal A SEC/DIV
distance x switch
(divisions) setting
3. For the unknown signal, adjust the A SEC/DIV
switch to a setting that provides sufficient horizontal
deflection to make an accurate measurement. Do not
readjust the SEC/DIV Variable control.
horizontal divisions. The arbitrary deflection factor is then
determined by substituting values in the formula:
Arbitrary
Deflection = 1.37 x 50/ts/div = 68.5ps/div
Factor
The time duration of the unknown signal can then be
computed by substituting values in the formula:
Time
Duration
68.5/is/div X 7 div = 480/ts
The frequency of the unknown signal is then calculated:
1
Frequency =
480 IIS
= 2.083 kHz
4. Establish an arbitrary deflection factor, using the
following formula:
Arbitrary horizontal A SEC/DIV
Deflection = conversion x switch
Factor factor setting
TV Line Signal
The following procedure is used to display a TV Line
signal.
1. Preset instrument controls and select NORIVI/TV
LINE ATRIGGER Mode.
5. Measure the horizontal distance of the unknown
signal in divisions and calculate its time duration using the
following formula:
2. Apply the TV signal to either vertical-channel input
connector and set the VERTICAL MODE switch to display
the channel used.
Time
Duration
arbitrary horizontal
deflection x distance
factor (divisions)
3. Set the appropriate VOLTS/DIV switch to display
0.3 division or more of composite video signal.
6. Frequency of the unknown signal can then be deter
mined by calculating the reciprocal of its time duration.
EXAMPLE: The reference signal time duration is
2.19 ms, the A SEC/DIV switch setting is 0.2 ms, and
the SEC/DIV Variable control is adjusted to provide a
horizontal distance of exactly 8 divisions.
Substituting the given values in the horizontal conver
sion factor formula:
Horizontal
Conversion =
Factor
2.19 ms
8 div X 0.2 ms/div
= 1.37
Continuing, for the unknown signal the A SEC/DIV
switch setting is 50 iis, and one complete cycle spans 7
4. Set the A SEC/DIV switch to 10 fts.
5. Set the A TRIGGER SLOPE switch to either
OUT:_/~ (for positive-going TV signal sync pulses) or
IN:^ (for negative-going TV signal sync pulses).
NOTE
To examine a TV Line signs! in more detail, either
the XI0 Magnifier or the Delayed-Sweep Magnifica
tion feature may be used.
TV Field Signal
The television feature of the 2235 can also be used to
display TV Field signals.
1. Preset instrument controls and obtain a baseline trace.
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