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Old 27th Mar 2019, 12:53 pm   #1
Autozavod
Triode
 
Join Date: Feb 2018
Location: London, UK.
Posts: 25
Default Assistance with modulator design

Hi everyone,

I rebuilt an old Soviet KVN-49 tv from the 50’s, and whilst I can run it by directly injecting a PAL signal into the video amplifier, my preference is to run it as intended.

One option is to feed a PAL signal into a pair of MC1374 chips using the design found here http://www.earlytelevision.org/405_modulator.html

Is there a knowledgeable soul who can suggest how I can modify this circuit to one of the frequencies below (and change it for FM sound modulation)? In particular the correct values for the coils and capacitors in the RF section?

best regards,
Matt

The Russian D system is:
Lines: 625
Frame rate: 25
Channel bandwidth: 8 MHz
Video bandwidth: 6 MHz
Vision/Sound separation: +6.5 MHz
Vestigial sideband: 0.75 MHz
Vision modulation: negative
Sound modulation: FM

Channel 1
Vision: 49.75 MHz
Sound: 56.25 MHz

Channel 2
Vision: 59.25 MHz
Sound: 65.75 MHz

Channel 3
Vision: 77.25 MHz
Sound: 83.75 MHz
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