Fundamental techniques on high quality PCM magnetic sound recorder is described (1) Principle of the analog to digital conversion (2) Comparison of characteristics between PCM and analog tape recorder (3) Clasification of the magnetic recording systems for PCM sound (4) Fundamental concept on error corection methods
The digital signal processing technique has been applied to the audio equipments and mainly to audio tape recorders in order to overcome the limitations of analog audio equipment. And it has been assured that the audio tape recorder (PCM recorder) is greatly superior to conventional analog tape recorders in respect of dynamic range, bandwidth, distortion and time base fluctuation of the reproduced audio signal. But there are remained some problems to solve for example dropouts of magnetic recording tapes. In this paper a summary and some steps to solve the problems of PCM recorder are reported.
It is well known that technical limitations of conventional analog tape recorders can be solved by pulse code modulation techniques. When transmitting a digital code with a signal as for example in PCM and if no error occurs in the code, the quality of the signal is not dependent on the characteristics of transmission medium. Nevertheless, the most of digital audio recorders previously developed was restricted as experimental use. This paper deals with a digital audio recording and playback system which are already used in pro-audio markets in the worlds. This system are developed by means of adaptor style configuration combined with video tape recorders. The adapter, which is a PCM audio processor, works as a signal convertor between audio signals, used without any modifications.