more scope for the elekterminal

Sometimes it can be very useful to connect the elekterminal (Elektor November and December 1978 issues) to an oscilloscope instead of to a TV. This of course, takes some doing, but if the circuit described here is used there should be no problems. The principle is very simple. If the oscilloscope has a Z input (which is usually the case, although the con- nection will probably be at the rear), the beam"s intensity may be regu- lated by an external voltage. Thus, a video signal can be directly fed to the Z input of an oscilloscope. If care is taken that the beam moves from left to right at the correct moment and obtains the right vertical deflection, a "TV picture" will appear on the screen. At the end of each row a horizontal synchronis- ation pulse is required. In the case of the elekterminal this is available at pin 4 of IC18 (N13). This output also contains the synchronisation pulses which make the beam fly- back at the end of each raster. This combined signal is fed to the syn...