Test Card 'M'-do you get the picture?

Problems in digital TV are already appearing. There is an absolute and immediate need to devise systems of test that allow the consumer products of today to continue to work in the future, as the full features of the DVB and Digital Television Group specifications are rolled out. Tests with test card 'M' have confirmed that receivers and set top boxes do not yet fully comply with these specifications. The major role played by test card 'M' in identifying and helping to correct these deficiencies is presented in this paper. Digital television systems are extremely complex, making them very difficult to test. Test card 'M' is a suite of specially crafted MPEG bitstreams which provides the solution for repeatable and structured testing without the need for sophisticated test equipment to evaluate the results and trace faults. This paper describes the contents of test card 'M' and our experiences of using it with the new generation of digital terrestrial receivers. By testing the decoder designs at the early stages, broadcasters and manufacturers can be assured that all the advanced features of digital broadcasting will be available when the need arises. The experience gained in test card 'M' development and application will be invaluable for testing of future digital TV systems in the UK and elsewhere.