Making TV Pattern Generator with ZNA234E
This Circuit uses the ZNA234E IC which makes available all the waveforms necessary to produce the crosshatch, test patterns on a television screen. The composite video output can be injected directly into the video input of a receiver or used to drive a modulator for connection to the aerial socket.
The circuit shown can be connected to a standard UHF TV set with 625 lines (CCIR standard), but by connecting pin 2 to ground instead of +5V, the output will produce 525 lines (EIA standard). In the circuit shown RV1 sets the vertical line width, RV2 sets the grey scale, RV3 sets the video/sync ratio, and RV4 sets the modulation depth.