Test and monitoring system for a digital video tape recorder/reproducer
AssigneeRobert Bosch GmbH
InventorsRolf Hedtke, Rolf Loos, Roland Mester, Jurgen Hansel
Life of this patent
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Abstract
A system for testing and/or monitoring a digital videotape apparatus makes use of the presence several identically equipped recording and reproducing channels to detect or test for errors by comparing the treatment of the same data in two or more channels. Comparisons are made at test nodes between reference "signatures" and actual "signatures" in normal operation or in test operation. Syndrome units are used to test or monitor circuits for protection against errors and for error correction. The monitoring and testing is done in a system which connects a microcomputer to test nodes of the equipment to be tested or monitored over a test bus.
Claims19
A system for monitoring a videotape recorder/reproducer having means for recording digital data in code blocks and having a plurality of channels each equipped with a plurality of Reed-Solomon encoders and a plurality of Reed-Solomon decoders, said system comprising:
- a microcomputer (114) for monitoring said recorder/reproducer;
- test bus means (100) for connecting said microcomputer to said recorder/reproducer;
- a multiplicity of test node connection means in said recorder/reproducer each permanently connected to a different group of components of said recorder/reproducer, at least some of said groups of components respectively including said syndrome forming means, for connecting said groups of components of said recorder/reproducer to said test bus means (100);
- a multiplicity of syndrome forming means (17, 28, 65, 95) respectively for each of said encoders and for each of said decoders connected respectively to said outputs of said encoders and decoders of said recorder/reproducer for producing syndrome values from data words and check words processed in said respective encoders and decoders;
- a null detection comparator (16, 29, 68, 96) for each said syndrome forming means, said respective comparators being included in those of said respective groups of components in which said syndrome forming means are respectively included, each said comparator having an input connected to the output of the respective syndrome forming means and an output connected to a said test node connection means for providing an error flag signal whenever a syndrome value other than zero is provided at the output of said respective syndrome forming means;
- means (2) for generating and applying a test signal simultaneously to each of said channels of said recorder/reproducer;
- comparing means (19, 55, 64) in said recorder/reproducer for detecting equality or inequality of said test signal content among said channels, each said comparing means having an output to provide an error flag signal newly generated by the respective comparing means to said test bus means (100);
- means in and associated with said microcomputer for registering the reporting each error flag signal and an indentification of a component group or component of said recorder/reproducer at which an error designated by a reported error flag signal was generated.
A system for testing a videotape recorder/reproducer having means for recording of video and audio television digital data in four channels after subdivision into four sectors which are shuffled by segments for recording in said four channels and more particularly having for each of said four channels an inner and an outer encoder and an inner and an outer decoder, said recorder/reproducer having first crosspoint switching means for signals to be recorded and second crosspoint switching means for signals to be reproduced, first picture field intermediate memory means interposed between each outer encoder and an inner encoder, second picture field intermediate memory means interposed between said second crosspoint switching means and each of said outer decoders, said system comprising:
- a microcomputer (114) for testing said recorder/reproducer;
- test bus means (100) for connecting said microcomputer to said recorder/reproducer;
- a multiplicity of test node connection means in said recorder/reproducer each permanently connected to a different group of components of said recorder/reproducer for connecting said groups of components of said recorder/reproducer to said test bus means;
- means under control of said microcomputer for generating and applying to an input of said recorder/reproducer a test signal providing a plurality of test televisions lines of contents designed to provide identical signals contemporarily in each of said four channels and in each of said four sectors in said recorder/reproducer and thereby providing said identical signals contemporarily in said channels;
- comparing means in said recorder/reproducer for detecting equality or inequality of said provided identical signals among said channels and among said sectors and for communicating an error signal to said microcomputer via a said test node connection means and said test bus means in the event of nonequality detection, said comparing means including equality/nonequality detection means at the following stages of recording and reproducing:
- (a) at the inputs of said respective outer encoders,
- (b) at the inputs of said respective inner decoders, and
- (c) at the respective outputs of said second crosspoint switching means, and
- means in and associated with said microcomputer for registering each said error signal together with an identification of a said component group to which said respective error signal relates.
Dependencies are inferred from the claim text.