How works volume OSD in a tv

[marco antonio]

I want to know how the volume is controlled in a Tv with an OSD since when I need to increase/reduce the volume, the bar is displayed on the screen but how is the path it follow from pushing the switch until heard the sound.
rgds
marco antonio

 

[rhaynes]

OSD is just a display indication of the volume setting, the actual volume is controlled by some circuitry in series with the audio path that can attenuate the audio signal. The setting of the attenuator is also passed to control some digital circuits that can overlay graphics onto the video to display the volume setting.

So when you push the volume up button the microprocessor or other logic increments the volume setting at the attenuator and also changes the digital setting of the OSD.


Is that the level of detail you are looking for?

Ray

 

[marco antonio]

Ray
Thanks for your response and I will appreciatte if you have some more detailed info with an example.
rgds
marco

 

[rhaynes]

For the actual volume control this is typical of the chips used:

**broken link removed**

And for the OSD part see this Wikipedia entry:

On-screen display - Wikipedia, the free encyclopedia

And here is a chip that does the all of the OSD part:

**broken link removed**

Then there is the microprocessor that accepts the buttons or IR control and send the volume data to the volume chip and the OSD data to the OSD chip.

To go into any more detail I would need more information as to the application or more specific questions.

Ray