04-10-2009, 03:14 PM
Abstract Test card for color TV is a widely used method to evaluate the quality of a TV set directly. We have made a test signal generator (which can also generate synchronizing (abbreviated to sync hereafter) signals) mainly based on microprocessor Z-80. Taking the advantage of microprocessor programming, combining with the technique of microprocessor, digital circuits and analogue devices, we use software as far as possible to generate signals directly or to simplify the controlling circuits. Those signals, such as composite sync signal, blanking signal and a series of test signals are originally realized by a number of sequential circuits and logical gates. Now, this test signal generator has smaller size, higher stability and lower cost compared with former ones which consist of more hardware. All of the programs are stored in EPROM. We can change the test patterns and their orders easily by changing the programs without changing the main structure of the system. On the other hand, varied kinds of non-standard TV sync signals and test patterns can also be obtained in this way.
