With radio, we know that music is transformed into electric waves in the mike. These waves transform the frequency of the carrier wave and modulate it. In the television camera, there is a kind of mosaic of tiny photographic cells. Through the lens, the image to be reproduced is transformed in the mosaic. the image is composed (as is a photo) of many little dots, some darker, some lighter. However, a picture is not transformed all at once. In fact, it is scanned. phoelectric cell by photoelectric cell. The ligter the image, the more the cell gives out a powrful ray. This is used for themodulation (the frequency) of the carrier wave. In the television receiver, this modulating signal is again decoded. In the image-tube of the equipment, a ray of electrons hits agains the screen in 625 lines at 25 times per second. The modulating signal enables the strength of this ray of electrons hits against the screen in 625 lines at 25 times per second. The modulating signal enables the strength of this rayof electrons to vary. Thus, certain parts of the screen are lit up in varying strengths in order to allow the original image to be reproduced, line by line! And yet we see nothing of this. At the moment when the last line is tranmitte, the luminous impression from the first is till present in the eye because of the eye's slow reaction. Thus we see all the lines in one single image...