Thanks Pieter. Regarding the UK system I VIF choice, I agree that alignment of the lower channel sound rejection point with channel B1 sound at 41.5 MHz is a plausible reason for the shift from 38.9 to 38.5 MHz. It could have been a standalone reason, or it could have been an additional reason for an otherwise desired upward shift in order to better accommodate receivers with dual-Nyquist IF bandpasses. In the latter case, it was likely the reason that determined the actual magnitude of that upward shift.
Somewhere there must be a BREMA document that would explain all. Maybe one day it will surface.
One of the questions implied in that VIF selection was how close could one get to the bottom edge of Band I, or rather the lowest carrier frequency in Band I without causing undue problems. In the French case the closest approach generally was between the 39.2 MHz SIF and the 41.25 sound carrier of channel F2. But border-area multisystem receivers used 39.9 MHz VIF for system L, and sometimes also for system E. In the French African case, system K’, the VIF was 40.2 MHz against an assumed channel one vision carrier of 42.25 MHz.
On that basis, perhaps the UK system I VIF could have been pushed as high as 40.25 MHz. But another limiting factor was image rejection for the (n+10) case, which would have indicated less than 40 MHz by an adequate margin. 39.5 MHz would have been close to, if not at that limit. So it effectively killed two birds with one stone.
The Philips 210 IF bandpass is quite interesting. It seems to be of the quasi-double Nyquist type, in that the 34.65 MHz -6dB point on the 405 Nyquist flank remains in place on 625, giving a 625 vision bandwidth of 4.85 MHz. But that flank is steepened up by the 33.9 MHz trap, not used on 405.
In the Italian case, it could be that for its own reasons, Philips decided that moving from 45.75 to 45.9 MHz was beneficial. The documentation that I can find all shows 45.75 MHz as the “official” VIF until the change was made to the European standard of 38.9 MHz.
The CCIR TV IF reports from 1959 Los Angeles through 1970 New Delhi all show 45.75 MHz. That from 1974 Geneva shows the change to 38.9 MHz.
I imagine that Philips would have had good reason to deviate. I understand that it was instrumental in choosing the 38.9 MHz number, as the reference given for that (which I haven’t seen) was an article in Funk and Ton no. 8, 1954, pp.129-138, “Choice of an intermediate frequency for television receivers to suit the C.C.I.R. standard”, by W. Holm and W. Werner. I imagine that was the same W. Werner who co-authored with the F. Kerkhof the Philips Technical Library book “Television”. And the same W. Holm who wrote the book “How Television Works.” The latter was a good “starter” book, and I still have my copy bought back in 1964.
I guess that a pertinent questions is was the deviation to 45.9 MHz general amongst the setmakers and tuner makers, or did Philips do that alone?
Cheers,