17-11-2021, 09:57 AM
(This post was last modified: 17-11-2021, 09:57 AM by ppppenguin.)
It's not just the line number conversion; that only affects vertical resolution which isn't very obvious on most pictures. It's also passing through two ADCs and two DACs, none of which are really high grade. Though they are not bad (to be fair, the Aurora and Hedghog use very similar ADCs and DACs)
Most test signals aren't going to show very much if vertical resolution is degraded. This is probably because in traditional TV systems, there was very little apart from the camera and display that affected vertical resolution. A zone plate is probably the most sensitive test signal because it represents all vertical and horizontal frequencies. A vertical frequency sweep would also work. Neither would show phase or time domain effects very well. I'm trying to envisage the vertical equivalent of pulse and bar. An ordinary crosshatch signal might well have visible effects. Each horizontal line is just a single line on each field.
That reminds me of trying a 625>405 converter with a crosshatch signal where the horizontal lines were out of order on the 2 fields. I can't remember which field is meant to be above the other but this signal was the wrong way round. The result was truly horrible after conversion.
Most test signals aren't going to show very much if vertical resolution is degraded. This is probably because in traditional TV systems, there was very little apart from the camera and display that affected vertical resolution. A zone plate is probably the most sensitive test signal because it represents all vertical and horizontal frequencies. A vertical frequency sweep would also work. Neither would show phase or time domain effects very well. I'm trying to envisage the vertical equivalent of pulse and bar. An ordinary crosshatch signal might well have visible effects. Each horizontal line is just a single line on each field.
That reminds me of trying a 625>405 converter with a crosshatch signal where the horizontal lines were out of order on the 2 fields. I can't remember which field is meant to be above the other but this signal was the wrong way round. The result was truly horrible after conversion.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
