(1) If the impedance changes, then stabilization is lost to the input of
the master sawtooth generator.
(2) To prevent an impedance change, a pad or attenuation system is in
series with the camera cable.
4. Horizontal Deflection System (fig 21, a foldout located at the end of Lesson
3). Horizontal deflection starts with horizontal drive which is obtained from the
camera pulse module that putt: out a negativegoing pulse. The drive signal is
isolated by emitter follower Q15, and is then applied to the horizontal sawtooth
generator circuit.
a. A master sawtooth waveform is generated by charging C1 through Q1, and
discharging it through Q2. Transistor Q3, an emitter follower, isolates and
prevents loading of the capacitor charging circuits.
b. Sinusoidal retrace is required to minimize spurious transients in the
yoke during horizontal retrace.
c. The output of emitter follower, Q3, applies the master sawtooth waveform
to each individual horizontal deflection amplifier on the horizontal deflection
module. This waveform would deflect the beam within the pickup tube horizontally,
and within tolerance if no differential errors existed, d. Differential.
correction waveforms are added to the master sawtooth waveforms in the individual
channels, which will provide differential linearity and width correction.
NOTE: The rest of the lesson on horizontal
deflection will be on the red channel. All
channels are basically the same (fig 22).
5. Red differential width controls the horizontal movement of the red electron
beam across the target of the pickup tube. This is accomplished by feeding a DC
control voltage through the camera cable and resistor R77 and applying it to a
capacitor which is discharged at a horizontal rate by transistor Q19.
a. The sawtooth which is developed by this circuitry can be either negative
or positive in potential. This negative or positive signal is then added to the
Red master sawtooth waveform. The end result is the ability to increase or
decrease the width of Red master horizontal deflection.
b. Red differential horizontal linearity is achieved by first generating a
sawtooth waveform in the same way it is done within the red width control, except
that only a positive sawtooth is needed.
c. The sawtooth is applied to an integrator circuit which converts the
sawtooth waveform into a positive parabola waveform. From this addition,
horizontal linearity is obtained.
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