CD-4

Over five years have elapsed since the CD-4 system was announced as a means of achieving quadra- phony from a disc record. The worldwide popularization of the CD-4 system is now making rapid progress, thanks to various factors such as the wider variety of soft- ware - about 1000 CD-4 albums have been released - improved, more compact cutting equipment, the development of high perform- ance PU cartridges, the high level of integration used in the demodu- lation circuit, etc. However, there seem to be various misunder- standings of the CD-4 system be- cause of some unfortunate occur- rences at the initial stage: played back sound was unsatisfactory be- cause of inferior service to end users during the course of the development, parties with differ- ing interests issued misleading publicity, etc. For this reason, in this paper, we would like to restate our policy on CD-4 and describe the present state of CD-4 technology to give readers a fuller understanding of the CD-4 system.