On Screen Displays with TV's

[grdthato]

Does anyone know how an On Screen Display works? For example, comcast
digital cable. How are text, menus, and graphics displayed and
overlayed? What type of electronics are needed to do this?

 

[Michael A. Terrell]

grdthato wrote:

Does anyone know how an On Screen Display works? For example, comcast
digital cable. How are text, menus, and graphics displayed and
overlayed? What type of electronics are needed to do this?

The same way its done in newer TV seds, with a chip designed to do
the OSD funtion. There a re a lot of ICs made for the job. Try a
search engine and a few well worded searchs will give you datasheets and
sample circuits.

--
Link to my "Computers for disabled Veterans" project website deleted
after threats were telephoned to my church.

Michael A. Terrell
Central Florida

 

[David L. Jones]

grdthato wrote:

Does anyone know how an On Screen Display works? For example, comcast
digital cable. How are text, menus, and graphics displayed and
overlayed? What type of electronics are needed to do this?

There are dedicated chips that do this.
You can get ones that take composite video in overlay the text and
output analog again, like the STV5730A.
Others are RGB devices with bigger memory for multiple pages and full
graphics. Phillips makes some that have 8051 micros embedded in them to
control it.
Others might be integrated into the main TV chipset, considering it's
all "system on chip" these days.

Dave