Abstract: A digital signal processor for recording an analog signal in the form of a PCM signal and/or for reproducing the PCM signal in the form of an analog signal. It has functions of generating a first and a second check code each by performing a modulo 2 operation and of adding a third check code to each of the first and the second check codes for detecting errors. The original signals can thereby be restored completely, even when up to two data sets have been subjected to errors.

Abstract: A digital audio signal recorder for obtaining coded signals having a first check code generator for generating the sum of module 2 for each bit of pieces of predetermined sampled data; and further has a circuit operatively coupled to said generator for arranging the sampled data, a first check code and a second check code at positions spaced on a time axis from each other. This invention also provides a method of generating such a digital audio signal. This invention is advantageous because it makes possible a low rate of redundancy and a simple decode circuit.

Abstract: An apparatus for detecting the recording and reproducing state of a video tape recorder used in conjunction with a pulse code modulation adapter and including a signal processor for comparing for a predetermined period data from signals transmitted from the pulse code modulation adapter apparatus to the video tape recorder with data from the signals received from the pulse code modulation adapter apparatus from the video tape recorder and detecting whether the video tape recorder is in the recording or reproducing state in dependence upon the result of the data comparison.