|
Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions. |
|
Thread Tools |
30th Jun 2005, 5:52 pm | #1 |
Retired Dormant Member
Join Date: Dec 2003
Location: Solingen, Germany
Posts: 727
|
easy 100% modulation adjustment (sound)
http://www.your-normwandler-page.de.vu/
Good evening, In my 405 modulator the sound input has a poti to adjust the modulation depth. To make the agliment easy I made a 100% modulation detector for the sound modulation depth adjustment. It is a red LED that flashes when you have overmodulation. So adjust the poti that the LED just not flashes to get 100% sound modulation. You only need two resistors a transistor and a LED. I build this very helpfull circuit in the MK III converter/modulator and in the London Birmingham modulator. Pics will follow soon, and I will update the converter/modulator thrads step by step. Kind regards Darius |
30th Aug 2006, 4:38 pm | #3 |
Retired Dormant Member
Join Date: Dec 2003
Location: Solingen, Germany
Posts: 727
|
Re: easy 100% modulation adjustment (sound)
Thanks for making it possible to update it.
An additional resistor from base to ground makes it possible to detect a lower modulation depth. Here you can see a modulator using this stage: https://www.vintage-radio.net/forum/...ad.php?t=10790 It is possible to drive an automatic level control ALC with this stage. I drawed the ALC stage alone for an easier understanding. Kind regards, Darius Last edited by oldeurope; 30th Aug 2006 at 4:42 pm. Reason: link and text |