Service manual
32 foreground/background colours programmable colour
(Latin, Cyrillic and Greek caracter sets) Character matrix 10x10
Volume control for one mono channel
The Video Front End section takes in the analogue Composite Video and Blanking Signal (CVBS), and from this extracts the required data, which is then decoded and stored in memory.
The extraction of the data is performed in the digital domain. The first stage is to select and convert the analogue CVBS signal into a digital form. This is done using 8 bit ADC sampling at 20.25 Mhz.
The digital data services transmitted in the VBI are selected and acquired separately form the video part. This is done by the use of an adaptive data slicer. The following data types can be extracted : 625 line World System Teletext (WST), VPS, WSS. The data is acquired and decoded by the teletext decoder (TPU), then stored in an SRAM lnterface.
Data Capture for VPS data (PDC system A)
Data Capture for Wide Screen Signalling (WSS) bit decoding