Abstract:
A data signal synchronizing circuit in which data signals are divided into groups of a predetermined number of bits, each having a synchronizing signal, any desired address signal and an error detection signal for detecting the error of this address signal, the groups of data signals being adapted to be written in a memory device in accordance with the address signals. The synchronizing circuit has a means (4) for detecting the synchronizing signal and a means (3) for detecting any error in the address signal. The synchronizing circuit further has an internal synchronizing signal generating circuit (6) and an internal address signal generating circuit (10). The internal synchronizing signal generating circuit (6) is driven when the error detecting means (3) detects judges that the address signal is correct so that the internal synchronizing signal generating circuit (6) generates an internal synchronizing signal which drives the internal address signal generating circuit (10). The address signal or the internal address signal is selectively supplied to the memory device (13) depending on whether the address signal is correct or wrong. According to the invention, it is possible to attain the synchronism correctly with a simple circuit arrangement.
Abstract:
Digital data, such as a digital audio signal which differs from a two-channel digital audio signal in sampling frequency and number of quantized bits, or display data or program data, can be recorded in the same signal format as that of a two-channel digital audio signal. A code signal specifying that either a two-channel digital audio signal or digital data has been recorded, and control data giving the linear velocity of a digital disc during reproduction are inserted into every frame of a recording signal. One block of digital data is formed of a predetermined quantity of data, and the same control data as that employed to control digital processing is recorded at least twice in each block. During reproduction, the digital disc is rotated to provide a constant linear velocity in accordance with the control data, and a reproduction circuit is supplied with a clock signal of a frequency corresponding to the transfer rate of the reproduced data. The reproduced digital audio data from the reproduction circuit is converted to analog data, and the passband of a low-pass filter supplied with the reproduced analog audio signal can be made to conform to the band of the reproduced analog audio signal.
Abstract:
Système de codage pour données binaires adapté notamment à l'enregistrement/reproduction magnétiques dans lequel les valeurs minimum et maximum entre les intervalles d'inversion de magnétisation sont limités de manière à accroître la densité d'enregistrement. Des données à six bits, comprenant des données à quatre bits et les données suivantes à deux bits dans une série de données binaires, sont converties en un code à neuf bits après la conversion selon le code dans une mémoire à accès séquentiel (5). En fonction de l'analyse effectuée sur les données à quatre bits dans un circuit de contrôle de modèle (4), un code à six bits est produit en réponse aux données à quatre bits ou bien un code à neuf bits est produit en réponse aux données à six bits. Lorsque la limite d'un code est "11", il est converti en "10" dans un circuit convertisseur de modèle "11" (11). On limite ainsi entre un et sept le nombre de bits de code de valeur "0" existant en continu dans les séries de code après la conversion et l'enregistrement magnétique est exécuté ensuite avec les inversions de mangnétisation en réponse aux bits de code de valeur "1".
Abstract:
Un systeme de codage de donnees binaires particulierement adapte a l'enregistrement et a la reproduction magnetique limite les valeurs minimum et maximum d'une distance de magnetisation d'inversion de maniere a obtenir une densite d'enregistrement plus elevee. Les donnees binaires sont divisees par tranches de deux bits et le code de chaque groupe de deux bits est entre dans une memoire morte (7) ainsi que les codes adjacents devant et derriere, p.ex. les deux bits precedents et les quatre bits suivants puis il est sorti apres avoir ete converti en un code a quatre bits. Dans la disposition des bits du code converti, le nombre de bits de codage "0" present sequentiellement entre le bit de code "1" en un point arbitraire et le code suivant "1" est limite, par exemple, de 2 a 8. La ligne de signaux-codes convertis est enregistree magnetiquement de telle maniere que l'on fait correspondre une magnetisation inverse a chaque bit de code "1".
Abstract:
Dans un systeme de memoire a grande capacite avec un support d'information telle qu'une bande magnetique (T), un procede de commande d'un moteur d'enroulement (16) permet de faire en sorte e l'intervalle de temps requis pour clarifier les resultats du controle d'erreur ne provoque pas de retard dans le depart du transfert pas a pas du support. Des pistes d'enregistrement sont formees en bandes coupant obliquement le sens longitudinal de la bande magnetique (T). Lorsqu'une tete magnetique rotative finit l'enregistrement ou la reproduction sur l'une des pistes d'enregistrement, une impulsion de signal de fin de donnees est generee, et le moteur d'enroulement (16) commence le transfert pas a pas de la bande magnetique (T), avant que les resultats du controle d'erreur des donnees reproduites ne soient con- Dans le cas normal d'absence d'erreur, une instruction est generee de maniere a poursuivre le transfert, et la tete magnetique rotative (14) effectue l'enregistrement et la reproduction sur la piste d'enregistrent suivante. Si une erreur est detectee, une impulsion de signal d'inversion de rotation est generee et le moteur d'enroulement (16) tourne dans le sens inverse de maniere telle a ce que la premiere piste d'enregistrement soit enregistree ou reproduite de nouveau.
Abstract:
Apparatus and techniques for converting analog data, preferably audio signals, to digital information, which digital information is preferably recorded from two separate main channels (11, 12) onto main tracks (22a, 22b) and includes a third or backup track (22c) for recording thereon partial or most significant portions of that information recorded on the main tracks. The invention involves apparatus and techniques of each data group on each main track and the backup track; checking (27) for synchronization codes arranged between data groups; and checking (30) for a match of that appropriate portion of the main track data against the data on the backup track, with, when potentially erroneous or questionable data is detected, the invention providing for comparison of main and backup track data groupings (31) for determining which is most likely correct or, in the case where neither data grouping is identifiable as most likely correct, the invention provides for substitution of last correct data or integration between good data. The preferred invention incorporates clocking at the signal input for data stabilization, and first-in-first-out circuitry (32) at the output for reducing the effects of wow and flutter to produce a very high quality conversion of digital to analog form to pass to a speaker system.
Abstract:
A magnetic storage device (10) for storing and retrieving data from a magnetic medium such as a magnetic tape (22). The magnetic storage device (10) includes a first write gap (14), a first read gap (16) and at least one of a second write gap (18) and a second read gap (20) with each gap operatively associated with the magnetic medium. A controller (30) is coupled to each gap (14, 16, 18, 20). The controller (30) senses an error from a gap (16, 20) and stores an error flag.
Abstract:
The present invention relates in general to digital data storage systems and, more particularly, to a method for determining whether the correct data bas been read from a storage medium in a digital data storage system. A data storage system (10) is disclosed that is capable of performing a double check on data read from a storage media (12) to determine whether the data is the data desired by a requesting host computer (30). If the data is not the desired data, the system discards the data before it reaches the host (30). The data storage system (10) uses a randomizer unit (18) having a variable initialization value. The initialization value is based upon the address of the data storage location being accessed by the host (30). If the initialization value used to read a piece of data is different than the value used to write the data, uncorrectable data errors result and the data is discarded.
Abstract:
An apparatus and method are disclosed for reducing the effects of thermal asperities and other anomalous conditions on disc drive read operations. An improved format for a data block (300, 400) is provided having first and second sync fields (308, 316, 408, 412) in which sync patterns are stored, the first and second sync fields being separated by a selected distance within the data block. The sync pattern of the second sync field enables synchronization of a disc drive read channel (160) to the user data in the data block when the read channel fails to be synchronized by the sync pattern of the first sync field. In one embodiment, control information used by the read channel to prepare for receipt of the user data is stored in control fields (310, 314) between the first and second sync fields; in an alternative embodiment, a portion of the user data is stored in a data field (410) between the first and second sync fields.
Abstract:
A method of performing spectral analysis of signals recorded by a magnetic recording or storage system is provided using a modified channel chip of the system. The modified channel chip enables measurement of harmonic components of the recorded signal. The method is performed by reading the recorded periodic analog signal and converting the signal into a discrete time periodic signal. The discrete time periodic signal is digitally sampled at predetermined intervals, and the digital samples are selectively accumulated in a register (341) or registers of the channel chip. Incoming digital samples are accumulated by alternately being added and substracted (345) to contents of single register (341). The accumulated results represent summations used to determine harmonic coefficients of the recorded signal. The harmonic sensor includes an arithmetic unit and a register (341) or register for accumulating the digital samples.