We all know that calibrating a televison receiver cannot be done accurately without using a pattern generator. Although adjusting the TV set using ordinary transmitted programs can
be helpful, this method cannot guarantee a good alignment of the picture appearing on the screen. A pattern generator is therefore a must if you want that vertical lines be really vertical
and horizontal lines be really horizontal.
The generator circuit featured here is designed for black and white TV sets. It generates seven plus two patterns. The two additional patterns are actually "no pattern" but they can,
perhaps in some cases, be of help. These are: full white screen (G) and full black screen (A). The circuit itself is very easy to construct since it uses a single IC and few discrete components.
The seven main patterns are: vertical lines (B), dots (C), gray scale (D), horizontal lines (E), and checkered lines (F). Potentiometers P1 adjust the width of the vertical lines while P2 adjust
the brigthness of the checkered lines. The synchronizing signal can be adjusted through P3. Potentiometer P4 varies the level of the output signal.
A: Full black screen
B: Vertical lines
D: Gray scale
E: Horizontal lines
F: Checkered lines
G: Full white (blank) screen
Parts Placement Layout
External Wiring Layout
Electronic Circuits volume 1.0 - Circuit Nr. 73
The complete data of the electronic circuit described above can be found in the following book and is available from Amazon.com.
Click on the image to view the book.