DIGITAL MAGNETIC RECORDING AND REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To enable diagnosing simultaneously functions of both signal processing circuits of a signal system and a reproduction system without being handicapped by a space and a cost, though a data compression system of a nonreversible system is adopted. SOLUTION: In a diagnosis mode, a picture input data limiting circuit 12 limits picture input data inputted to a DCT operation variable length coding 3 so that a data value is varied making 1 DCT block or a block having magnitude of an integer multiple of 1 DCT block as the maximum unit. In DCT operation variable length coding, code quantity of a DC component is not reduced in a signal processing of after that as an AC component, also all AC components are made zero. and do not appear. Therefore. picture input data inputted to a recording system 1 coincides with output data from a reproducing system 2 perfectly.