The Amp Bias Controversy

[Murphyv310]

Bell seems to have used this method in a few sets, the grid is biased with a small positive voltage and the positive going video further turns the valve on, on syncs there is then a clipped sync pulse on its anode, I've hunted for a diagram but only found an explanation.
Pye also hold a patent for a very similar sync separator circuit.
Used in a prewar model.
I'm using a phone and can't seem to copy and paste either article.