Long-tailed pair with cathode auto-biasing. Figure 3 from A. D. Blumlein's US Patent 2185367 (British 482740), priority from 1936-07-04. The original was slightly altered - I removed output cathode followers, w More
Picryl description: Public domain image of a military aircraft, aviation, air forces, free to use, no copyright restrictions.
The Blumlein wafeform - early British standard of video signal, proposed by A. D. Blumlein and enacted by the Television Advisory Committee in 1936 - in operation till 1986. Русский: Британский стандарт видео More