Marconi Instruments P4428, Техническое руководство

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Operating and Technical Descriptions
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7.
OPERATING FACILITIES AND ADJUSTMENTS
7.1.
Electrode Supplies
Pre-set controls are located on the scan board.
i) G2 Fixed voltage 175 volts
ii) G3 Pre-set for 80 volts (RV109)
iii) G4 Fixed voltage 135 volts
iv) G1 Variable from 0 to -60 volts (RV111)
v) Target (CPS) Pre-set to 0 volts
7.2. 8.7 Volt Supply
This basic supply is pre-set in the voltage stabiliser unit (VR400 [VR1]).
7.3. Magnetic Focus
The control is located on the scan board (RV116).
NB The magnetic focus control should be used to adjust the tube
electrical focus in preference to varying G3.
7.4. Line Linearity
A saturable reactor is used to control the line linearity and width. It is
located on the scan board (L100). [SMT version requires turns to be
adjusted]
7.5. Scan Adjustments
The following controls are provided:
horizontal shift RV101; vertical amplitude RV112; vertical shift RV113.
7.6. Video Adjustments
Set the alignment controls (RV102, RV103 scan board) for even target
illumination and adjust the shading and black level controls (video
board) as covered in the picture acquisition section 6.3.
7.7. Circular Blanking
To increase the signal out of the tube it is usual to overscan the target.
This also prevents charging of the unscanned portion of the TGS
crystal. The edges of the resultant circular picture have bright
highlights. A circular blanking generator is provided whose output is
used to gate the video waveform. By adjusting the 'size' control the
unwanted video can be masked, (RV206, video board). The shape of
the circle is adjusted by a pre-set control on video board (RV207). The
shift controls may be used to centre the target image.
NB Correct circular blanking is essential for automatic video balance
and iris function.