old_tv_nut |
12-20-2023 04:29 PM |
Quote:
Originally Posted by Penthode
(Post 3254851)
Curious about your statement step backward? Agreed there is the registration issue with a three tube camera. But unless the field sequential channel bandwidth was made wider, the resolution would have been noticably worse. CBS Field Sequential for a 6 MHz channel optimally would be only about 340 line to even bring the Kell Factor to 0.6. CBS was dependent upon crispening circuits to make up for the poor horizontal resolution.
On the other hand, this is a closed circuit set up which would have meant channel bandwidth would not be restricted. And the new tricolor CRTs under development by both CBS and RCA could have been used.
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The chroma bandwidth of NTSC is much less than the luma bandwidth. The field sequential system has the same resolution for color details as for luminance details, although this is less than the NTSC luminance resolution. In closed circuit use, NTSC can have greater luma bandwidth but still has the lower chroma bandwidth. For another thing, the luminance bandwidth in the NTSC monitors was compromised by the subcarrier trap. They did not have comb filters.
In closed-circuit medical use, the deficiency in the field sequential vertical resolution due to the reduced number of scan lines could be compensated by zooming in when necessary.
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