Kramer Electronics Ltd.
15
8.2 Engineering...
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Items in this section will alter the basic operation of the Scan Converter. The changes are generally of a highly
technical nature and should only be made when they are understood. Please read each item in this section
carefully before making any alterations.
When the ‘Engineering...’ message appears, press and hold both the + and – Buttons simultaneously for
approximately 2 seconds and then release both buttons.
Settings changed in this mode can be stored in Non-Volitle Memory the same way as other settings.
Note
– Great caution should be exercised before making any adjustments covered in this section.
8.2.1
ADC Ref. - Input RGB Level
The Scan Converter takes the RGB analog signal from the computer (destined for the computer monitor) and
converts it to a digital signal in order to perform signal processing and scan conversion. The actual device that
does this is an Analog-to-Digital converter (ADC) and changing the upper reference level to this is similar to a
Brightness Control, but will also clip colors that are too bright to the maximum brightness level. If this is
incorrectly set, then certain colors, such as yellow, may appear washed out or even come out as white. This
adjustment is factory set and should not normally need altering.
It is highly recommended that this value is only adjusted when problems arise. A Color Bar Test Pattern
should be displayed on the computer screen. An oscilloscope must be connected to the unit’s video
output to allow precise monitoring of the adjustment’s result.
Pressing the + Button increases the voltage at the ADC reference input. This makes the sampled image
darker and reduces 'clip' effects.
Pressing the – Button decreases the voltage at the ADC reference input. This makes the image brighter,
but at some point will start to 'clip' the RGB input.
The factory setting allows for an input up to 0.8V, thus allowing for out-of-tolerance RGB inputs.
8.2.2
DAC Ref. - Output Video Level
The Digital-to-Analog Converter (DAC) changes the digital data output from the processing circuit into an
analog form that can be displayed on a standard video monitor or TV. Altering the reference level has an effect
similar to changing the Contrast of the output video signal.
It is highly recommended that this value only be adjusted when problems arise. A Color Bar Test Pattern
should be displayed on the computer screen. An oscilloscope must be connected to the unit’s video
output to allow precise monitoring of the adjustment’s result.
Pressing the + Button increases the voltage at the DAC reference input.
Pressing the – Button decreases the voltage at the DAC reference input.
8.2.3
CV Filter - For Composite Video
The Scan Converter allows some control over the amount of filtering on the Composite Video output. Altering
this may give a clearer image or reduce dot-crawl.
In most circumstances, this should never need changing.
Pressing the + Button increases the value, thus applying more filtering.
Pressing the – Button decreases the value, thus applying less filtering.
8.2.4
Adj. Osc. - For Subcarrier Frequency Adjustment
This fine-adjusts the Scan Converter's internal oscillator, which is used to generate all timings when not in the
Genlock Mode (In Genlock Mode on the VP-705SC and VP-706SC, the External Reference Signal is used
instead). Specifically, it adjusts the Subcarrier Frequency of the PAL or NTSC signal being generated. This
frequency is factory set, but may need adjusting under certain conditions.
Press the – Button to reduce this value (from the 0 default) to lower the Subcarrier Frequency.
Press the + Button to increase this value increase the Subcarrier Frequency.
8.2.5
SC/H Phase – For Video Output
This adjusts the Phase Delay between Subcarrier and Horizontal Sync signal.
This adjustment has no effect when the Studio Genlock feature is active.
This adjustment is normally only required for studio setups, where the actual phase relationship can be
measured.
The value of 4 is the default and corresponds to approximately 0 degrees shift. The remaining values are
indicated in the following table:
