21-02-2018, 12:24 PM
(21-02-2018, 03:09 AM)Synchrodyne Wrote: But there was definitely a penalty in terms of 625 vision bandwidth. 4.25 MHz (against the nominal 5.0 MHz) for System B was not very good, but 4.25 MHz (against the nominal 5.5 MHz) for System I surely fell into the grim category. Considering that Pye was a strong proponent of 625, one would have expected it to have designed prototype receivers that extracted the maximum from the system, including close to full vision bandwidth. (Not to mention the use of gated black level AGC, and black level retention/restoration.) One may hope that the production version got close to 5.5 MHz vision bandwidth.
I wonder if this could be the System G set I referred to with it's sound IF moved to 6MHz for System I?
In which case wouldn't it have made more sense to move the vision IF to the UK standard's specified 39.5MHz? This would have improved the 625-line vision response to 4.85MHz. Again, not good but a lot better than 4.25MHz!
