Patent EP0142613A1 successfully refreshed from Google Patents.
EP0142613A1
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Method and apparatus for recording and replay of digital audio data
Assignee: Harman International Industries Inc
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Filing: 1984-07-23
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Granted: —
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Expires: 2004-07-23
Abstract
Abstract For both recording and replay, a digital audio tape (14) is accelerated very rapidly by a motor servo (9), motor (8) and capstan (7) so that the tape speed overshoots nominal speed range before settling back to this range in an oscillatory manner. The digital samples are recorded and replayed via a head (15), a random access memory (17) and input/output electronics (19). During recording, the store (17) is precharged by starting to write in as soon as acceleration is initiated. Readout to the tape is initiated as soon as the tape first reaches the nominal speed range. Uniformity of samples as recorded on the tape is preserved by clocking a read address generator (21) at a rate proportional to tape speed, signaled by a tachometer (7). The write address generator is clocked at the constant sampling rate. For replay the write address generator is clocked at the tape speed rate while the read address generator (21) is clocked at the constant sample rate. Write in and read out are both initiated when the tape speed first reaches the nominal range. The addresses provided by the generators (20 and 21) are compared by a comparator (22) which provides a reference signal to the servo (9) in an arrangement such as to adjust the tape speed always in the sense to maintain a constant degree offilling of the store (17).
Inventors
- 👤 Roger Dr. Lagadec
- 👤 Guy William Whitsey Mcnally
- 👤 Philip Stuart Gaskell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 03:24
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10527; G11B15/00; G11B15/18; G11B15/46; G11B15/52; G11B20/22; G11B20/225; G11B27/00; G11B27/002; G11B27/02; G11B27/031; G11B27/032; G11B27/10; G11B27/11; G11B27/13; G11B2220/00; G11B2220/90; G11B2220/91; G11B2220/913
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
80 words
A method of effecting fast start-up of a recording or replay operation of digital information on a magnetic tape having a nominal tape speed range, characterised in that the tape is accelerated so rapidly as to overshoot the nominal tape speed range before stabilizing in that range, and in that recording on to the tape from a digital store or replay from the tape into the digital store is initiated substantially before the speed has stabilized in the said range.
Claim 2
Independent Claim
80 words
A method of effecting fast start-up of a recording or replay operation of digital information on a magnetic tape having a nominal tape speed range, characterised in that the tape is accelerated so rapidly as to overshoot the nominal tape speed range before stabilizing in that range, and in that recording on to the tape from a digital store or replay from the tape into the digital store is initiated substantially before the speed has stabilized in the said range.
Claim 3
Dependent Claim
28 words
A method according to claim 1, wherein the rate at which digital information is transferred between the tape and the store is controlled in dependence upon tape speed.
Claim 4
Dependent Claim
47 words
A method according to claim 2, wherein the store is a random access memory with a cyclic read address generator and a cyclic write address generator, one address generator is clocked at a fixed rate and the other is clocked at a rate corresponding to tape speed.
Claim 5
Dependent Claim
53 words
A method according to claim 3, wherein the read and write addresses are compared to determine the degree of fill of the store and, once the tape speed has stabilized, the tape speed is controlled in. dependence upon the degree of fill so as to tend to maintain the degree of fill constant.
Claim 6
Independent Claim
47 words
A method according to any of claims 1 to 4, wherein the recording on to the tape from the digital store or the replay from the tape into the digital store is initiated substantially at the time when the tape speed first reaches the nominal speed range.
Claim 7
Independent Claim
59 words
A method according to any of claims 1 to 5, wherein, during recording, writing of the digital information into the store at a constant rate is initiated when acceleration of the tape is commenced and read out from the store to the tape is initiated substantially at the time when the tape speed first reaches the nominal speed range.
Claim 8
Independent Claim
51 words
A method according to any of claims 1 to 5, wherein, during replay, writing of the digital information into the store from the tape and read out' from the store at a constant rate are both initiated substantially at the time when the tape speed first reaches the nominal speed range.
Claim 9
Independent Claim
37 words
A method according to any of claims 1 to 7, wherein two tape machines are simultaneously started up and synchronized by eliminating excess data from whichever store has filled more than the other during the fast start-up.
Claim 10
Dependent Claim
28 words
A method according to claim 8, wherein the synchronization by elimination. of excess data is effected substantially when the slower machine first reaches the nominal tape speed range.
Claim 11
Dependent Claim
28 words
A method according to claim 8 or 9, insofar as dependent on claim 3, wherein the elimination of excess data is effected by jumping the read address generator.
Claim 12
Dependent Claim
98 words
ll. Apparatus for carrying out the method according to claim 1, comprising a tape machine, a store connected between record and replay head(s) of the machine and input/output electronics for the digital information, means for starting the machine in such a way that the tape is accelerated so rapidly as to overshoot the nominal tape speed range, and a control unit for initiating the recording on to the tape from the digital store or the replay from the tape into the digital address generator substantially at the time when the tape speed first reaches the nominal speed range.
Claim 13
Dependent Claim
91 words
Apparatus according to claim 11, wherein the store is a random access memory with a cyclic read address generator and a cyclic write address generator, and the control unit has a record mode in which the write address generator is clocked at a fixed rate while the read address generator is clocked in dependence upon a signal representing tape speed, and a replay mode in which the read address generator is clocked at a fixed rate while the write address generator is clocked in dependence upon the signal representing tape speed.
Claim 14
Dependent Claim
39 words
Apparatus according to claim 12, comprising means for comparing the address provided by the two address generators and means for controlling the tape speed so as to tend to maintain the degree of fill of the store substantially constant.
Claim 15
Dependent Claim
38 words
Apparatus according to claim 12 or 13, wherein two tape machines have a common control unit or linked control units adapted to jump the read address generator of one machine so as to bring the machines into synchronisation.
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