Philips circle pattern
The Philips PM5544 is a television pattern generator, most commonly used to provide a television station with a complex test card. It has been in use since the dawn of colour television, and is the most commonly used test card generator, with only the SMPTE bars and the BBC Test Card F coming close to its usage. The BBC even use it themselves, as Test Card G, and most other broadcasters using a 625 line system such as PAL or SECAM also use it.
A widescreen capable version of the unit, the PM5644, also exists.