23-08-2023, 11:43 AM
A made for Belgium multi-standard TV receiver will need to operate on 819 lines systems E and F, the latter being the narrow vision bandwidth system with the same vision-sound spacing as as system B but with AM sound. As far as the IF amplifier stages are concerned narrow bandwidth 819 and 625 CCIR system B are no more difficult to implement as 405/625 switching arrangements, in fact probably simpler. The real difficulties begin with the requirement to receive full bandwidth 819 transmissions. Vision-sound spacing is 11.15Mhz compared with CCIR 5.5Mhz. Sound IF amplifier might employ double-conversion in the same manner as certain Murphy TV sets equipped with FM radio.
Attachment shows a Peto-Scott TV monitor which has automatic switching between 405 and 625 lines.
Geordie McBoyne.
Attachment shows a Peto-Scott TV monitor which has automatic switching between 405 and 625 lines.
Geordie McBoyne.
