Tektronix AWVG1, User Manual

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Appendix C: Zone Plates
AWVG1 Wideband Video Generator User Manual
C- 7
TG 2000 display: K (phase)
Units: cyc (cycle)
Range: --0.5 to 0.5 (default = 0.00000)
K
∅
is the initial phase of the pattern; it cannot create a pattern by itself. To see
the effects of this adjustment, first set the K
X
coefficient to approximately 0.75
and set a waveform monitor to view the line waveform. Then adjust K
∅
. The
sine wave will begin on each line at the selected point in the cycle. Note that
0.25 cycle corresponds to a phase of 90 degrees (or
π
/2 radians); recall that the
sine of 90
°
is 1.0 and the sine of --90
°
is --1.0. When K
∅
= 0.25, the pattern will
begin in the upper left corner of the screen as white; when K
∅
= --0.25, the
beginning will be black.
TG 2000 display: KXT (T ch H freq)
Units: c/aph/s (c/aph per second)
The K
XT
parameter controls the change in horizontal sine frequency over time.
Setting K
XT
to 1.0, for example, will cause the horizontal frequency to increase
by one c/aph each second. If K
X
is 0.0, then the frequency will be 10 c/aph after
ten seconds, 20 c/aph after twenty seconds, and so forth. The frequency will
increase until it reaches the maximum for the active video standard; the phase of
the signal will then flip by 180
°
(the sine wave will become negative) and the
frequency will increase through DC, when the cycle will begin again.
TG 2000 display: KYT (T ch V freq)
Units: c/aph/s
The K
YT
parameter controls the change in vertical sine frequency over time.
Setting K
YT
to 1.0, for example, will cause the vertical frequency to increase by
one c/aph each second. If K
Y
is initially 0.0, then the frequency will be 10 c/aph
after ten seconds, 20 c/aph after twenty seconds, and so forth. The frequency will
increase until it reaches the maximum for the active video standard; the phase of
the signal will then flip by 180
°
(the frequency will become negative) and the
frequency will increase through DC in a repetitive cycle.
TG 2000 display: KT (T freq)
Units: c/s (cycles per second)
The K
T
parameter, if used alone, does not create a pattern. Instead the entire
screen cycles (sinusoidally) between white and black. The effect is similar on
either line or field display of a waveform monitor.
Typically, a small K
T
coefficient is set to add apparent motion to a standard
circle, sine wave, or sweep pattern. To see the picture effects of this parameter,
select any of the standard zone plates and vary K
T
. The K
T
coefficient can be
positive or negative; the sign will determine the direction of the pattern’s motion.
K
Φ
Parameter
K
XT
Parameter
K
YT
Parameter
K
T
Parameter