Mitsubishi C-3419: Difference between revisions

Adding TVL derivation section explaining calculation methodology (via update-page on MediaWiki MCP Server)
Revising TVL derivation section with more accurate bandwidth analysis and honest uncertainty (via update-page on MediaWiki MCP Server)
 
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== TVL derivation ==
== TVL derivation ==
The 576 TVL figure is derived from the maximum horizontal resolution supported by the AED 512/767 graphics terminals that drove these monitors. Per the AED users manual, the highest resolution raster mode is 768×575 pixels.
The 576 TVL figure is derived from the AED 512/767 graphics terminals that typically drove these monitors. Per the AED users manual, the highest resolution raster mode is 768×575 pixels. Since TVL measures horizontal resolution across picture height, the pixel count is adjusted for 4:3 aspect ratio:


Since TVL (TV lines) measures horizontal resolution across picture height, the horizontal pixel count must be adjusted for aspect ratio. For a 4:3 display:
: 768 pixels × (3 ÷ 4) = '''576 TVL''' (addressable)


: 768 pixels × (3 ÷ 4) = '''576 TVL''' (addressable)
'''Could the monitor resolve more with a different source?'''
 
The monitor's video bandwidth is specified at 20 MHz (±3dB). This represents how fast the video amplifier can switch the electron beam intensity. At the maximum 24 kHz horizontal scan rate, each line is ~41.7 µs, with ~32 µs of active video (after blanking). A rough estimate:
 
: 32 µs × 20 MHz = ~640 cycles (line pairs) per line
 
Applying real-world factors (the -3dB spec means signal is already attenuated ~30% at that frequency), practical resolution from the electronics might be 500–600 pixels horizontally — which aligns reasonably well with the 768-pixel AED mode.


This represents the theoretical addressable resolution. Effective resolution with real-world content would be lower depending on the Kell factor applied (typically 0.7 for interlaced content, ~0.85 for progressive/static graphics).
'''Unknowns:'''


Note that the monitor's 20 MHz video bandwidth (±3dB) could theoretically support significantly higher resolution — the raster addressing of the AED terminal is the limiting factor, not the monitor's analog circuitry.
The shadow mask pitch is not specified in the AED manual. Without knowing the phosphor dot spacing, we cannot determine whether the video amplifier or the shadow mask is the true resolution bottleneck. The 576 TVL figure should be considered an estimate based on the AED system configuration, not a definitive monitor specification.


{{CRT voltage range
{{CRT voltage range
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