[Graham G3ZVT]

See the images in post #34 in this thread.

That circuit is the brainchild of Peter Scott.

Although the pulse timings out of the graphics card are immaculate, the waveform lacks the trains of so-called Broad Pulses in the field blanking interval of the broadcast standard signal. Peters circuit endeavours to generate them and insert them into the signal. Without this enhancement, many sets will struggle to show any interlace, although, it has to be said that with a small screen you might not even notice.

You do need an oscilloscope to set it up.

<Edit> Hi Peter!