An accurate measuring system for VTR magnetic track
A novel design is presented, and the corresponding measuring system, which can be used to calibrate the servomechanism of a VTR (video tape recorder), to test the assembly errors of the video head drum assemblies, and to determine the exchangeability of the VTR, has been built. This design is based on the principle of the Bitter pattern method to show the magnetic track and the digital image processing technology, as well as the precise electromagnetic micromotion device. The accuracy of the previous measuring system depends on the location accuracy of the specimen stage of the measuring microscope, and it is about 0.5-1 mu m. In the present system, the measuring precision depends on the system amplification and the resolution of the digital image processing interface. Therefore, it is possible to improve the measuring accuracy of this system to deep submicrometer. As a result, the distance measurement precision of the present measuring system reaches 0.2 mu m. >