Why Did NBC Use Trinitrons?

[old_tv_nut]

Originally Posted by zenith2134

The HF video response rolloff that old_tv_nut mentioned, may be a reason why none of my vintage Trinitrons have a sharpness control? Since the sharpness control alters the high frequency of the video signal.
Just wondering.

A sharpness control could still act on the mid frequencies - deleting it is mainly a cost saving. However, there is another technical point - the typical sharpness control was a simple RC circuit that can affect the amplitude of overshoots (following an edge), but not the pre-shoots. In a set with no sharpness control, usually the IF response would provide some pre-shoot and a fixed RC circuit would provide a matching amount of overshoot. A really good sharpness control would involve a short delay line to produce both preshoots and post (over) shoots, and the control would vary the amplitude of both equally. This sort of control was provided on professional monitors and was labeled "aperture," as it compensated for the finite aperture of the electron guns in the camera and CRT. Later, when analog ICs were used in consumer sets, it was possible to get a symmetrical pre/post shoot of adjustable but equal amplitude.

For example, see US patent 4,296,435
http://patft.uspto.gov/netacgi/nph-P...tl&RS=IN/Bretl

[TVTim]

Maybe they were bought at Crazy Eddies. His prices were "insane"! and they were very big retailer in NY.