EP0368511A2
Expired / Lapsed
EP
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Synchronization of record media transports
Assignee: Ampex Systems Corp
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Filing: 1989-10-25
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Granted: —
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Expires: 2009-10-25
Abstract
Abstract In a digital tape recording system for video and sound signals, in which information in each track is stored in plural sectors having synchronizing preambles that aid in synchronizing the playback of the information, special preambles containing a frequency component that is lower than normal are used for the first sector of the first track in each video frame or field. The normal and special preambles are produced by passing the binary code "...01010101..." (in the case of all but the first sector of each frame or field) or "...011011011011..." (in the case of the first sector) through a Miller Channel Code encoder to produce, in the first case, a synchronizing square wave fluctuating at one-fourth the bit presentation frequency, and in the second case, a synchronizing quare wave fluctuating at one-sixth the bit presentation frequency. Special resonant circuits associated with the playback circuitry detect the special lower frequency component and signal the precise start of a new frame or field. This signal is used for capstan synchronization, head positioning during playback, and head positioning during editing when the record, heads are used as playback heads so that they may be properly positioned to overwrite individual sectors on a track without overwriting other sectors.
Inventors
- 👤 Maurice G. Lemoine
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 15:45
CPC Classifications
G; G11; G11B; G11B20/00; G11B15/00; G11B15/18; G11B15/46; G11B15/467; G11B15/4673; G11B15/4675; G11B15/4676; G11B27/00; G11B27/02; G11B27/031; G11B27/032; G11B27/036; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B27/3027; G11B27/32; G11B2220/00; G11B2220/20; G11B2220/21; G11B2220/215; G11B2220/216; G11B2220/90
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
124 words
Apparatus for synchronizing the transfer of information between a playback station and a record station comprising: means for extracting a playback signal from record medium at said record station; pattern detection means into which said playback signal is fed for providing an indication whenever a predetermined pattern is presented in said signal; means for extracting a time reference from said playback station; comparison means for indicating whether said indication is properly synchronized with said time reference; means controlled by said comparison means for adjusting the playback speed at said record station to achieve playback synchronization between said indication and said time reference; and means responsive to the achievement of playback synchronization for causing said record station to record signals presented by said playback station.
Claim 2
Dependent Claim
124 words
Apparatus for synchronizing the transfer of information between a playback station and a record station comprising: means for extracting a playback signal from record medium at said record station; pattern detection means into which said playback signal is fed for providing an indication whenever a predetermined pattern is presented in said signal; means for extracting a time reference from said playback station; comparison means for indicating whether said indication is properly synchronized with said time reference; means controlled by said comparison means for adjusting the playback speed at said record station to achieve playback synchronization between said indication and said time reference; and means responsive to the achievement of playback synchronization for causing said record station to record signals presented by said playback station.
Claim 3
Dependent Claim
56 words
Apparatus in accordance with claim 1 wherein the means for extracting a playback signal at said record station includes record head means having at least one record head for utilization in a playback mode to extract a playback signal from the record medium and in a record mode to record signals presented by said playback station.
Claim 4
Dependent Claim
38 words
Apparatus in accordance with claim 2 further comprising means for placing at least one of said record heads periodically in said playback mode during recording to provide said indication to maintain synchronization between the playback and record stations.
Claim 5
Dependent Claim
35 words
Apparatus in accordance with any of claims 1 to 3 wherein the playback signal comprises sectors preceded by synchronizing signals, in which said predetermined pattern comprises a form of synchronizing signal that precedes selected sectors.
Claim 6
Dependent Claim
47 words
Apparatus in accordance with claim 4 wherein said predetermined pattern comprises a preamble that contains a frequency component at a submultiple of the bit presentation rate of the playback signal, and wherein said pattern detection means includes a circuit selectively responsive to the frequency of said component.
Claim 7
Dependent Claim
20 words
Apparatus in accordance with claim 5 wherein said frequency is one-sixth of the bit presentation rate of the playback signal.
Claim 8
Dependent Claim
62 words
Apparatus in accordance with any of claims 1 to 6 further including means for extracting a control signal from the record medium at each record station; and means responsive to said control signal for adjusting the playback speed of the respective record medium transport at each record station to achieve coarse synchronization adjustment of the respective record medium and said time reference.
Claim 9
Dependent Claim
185 words
A digital recording system wherein information is recorded digitally in predetermined sectors at a selected substantially constant bit rate on a record medium utilizing a self-clocking channel code operating at said bit rate, said information being recorded over periodic cycles each comprising a plurality of said sectors, the sectors corresponding to respective intervals of information over each periodic cycle with a predetermined one of said sectors in each cycle corresponding to a particular interval in the respective cycle, the system including: means for providing a succession of binary bits at said bit rate according to a bit pattern that provides a periodic signal upon encoding according to said channel code, the period of said periodic signal being a multiple of the bit period; means for appending said periodic signal to the information in each of said predetermined ones of said sectors being recorded; means for selectively detecting recorded signals having the frequency of said recorded periodic signal by producing detection signals corresponding thereto; and means responsive to said detection signals for producing periodic timing signals identifying respective times in respective periodic cycles of recorded information.
Claim 10
Dependent Claim
185 words
A digital recording system wherein information is recorded digitally in predetermined sectors at a selected substantially constant bit rate on a record medium utilizing a self-clocking channel code operating at said bit rate, said information being recorded over periodic cycles each comprising a plurality of said sectors, the sectors corresponding to respective intervals of information over each periodic cycle with a predetermined one of said sectors in each cycle corresponding to a particular interval in the respective cycle, the system including: means for providing a succession of binary bits at said bit rate according to a bit pattern that provides a periodic signal upon encoding according to said channel code, the period of said periodic signal being a multiple of the bit period; means for appending said periodic signal to the information in each of said predetermined ones of said sectors being recorded; means for selectively detecting recorded signals having the frequency of said recorded periodic signal by producing detection signals corresponding thereto; and means responsive to said detection signals for producing periodic timing signals identifying respective times in respective periodic cycles of recorded information.
Claim 11
Dependent Claim
32 words
A system according to claim 8 wherein said means for appending appends said periodic signal as a preamble to the information being recorded in each of said predetermined ones of said sectors.
Claim 12
Dependent Claim
63 words
A system according to claim 8 or 9 wherein the recording system includes a playback head, the system further comprising means responsive to said detection signals for producing magnitude signals indicative of the magnitude of said detection signals, and means responsive to said magnitude signals for controlling the relative positions of the record medium and the playback head to maximize said magnitude signals.
Claim 13
Dependent Claim
48 words
A system according to claim 8 or 9 further comprising means for providing a timing reference signal, and means responsive to said periodic timing signals and said timing reference signal for driving the record medium at a rate synchronizing said periodic timing signals and said timing reference signal.
Claim 14
Dependent Claim
136 words
A data handling system for managing information organized into sectors which information includes a time base reference, which system includes: means for generating a preamble for said sectors whose primary function is to aid in synchronizing the extraction of information from the sectors; means for packaging the information into sectors; time base reference detection means for detecting particular sectors which correspond to time base reference points in the digital information; preamble modification means coupled to said means for generating a preamble and actuated by said time base reference detection means for causing a modified preamble to be generated for said particular sectors that correspond to time base reference points; and modified preamble detection means to which said sectors and preambles are presented for detecting said modified preambles and for indicating when a modified preamble is detected.
Claim 15
Dependent Claim
136 words
A data handling system for managing information organized into sectors which information includes a time base reference, which system includes: means for generating a preamble for said sectors whose primary function is to aid in synchronizing the extraction of information from the sectors; means for packaging the information into sectors; time base reference detection means for detecting particular sectors which correspond to time base reference points in the digital information; preamble modification means coupled to said means for generating a preamble and actuated by said time base reference detection means for causing a modified preamble to be generated for said particular sectors that correspond to time base reference points; and modified preamble detection means to which said sectors and preambles are presented for detecting said modified preambles and for indicating when a modified preamble is detected.
Claim 16
Dependent Claim
30 words
A system in accordance with claim 12 further including data encoding means through which said sectors and their preambles are passed prior to presentation to said modified preamble detection means.
Claim 17
Dependent Claim
55 words
A system in accordance with claim 12 or 13 wherein the means for generating a preamble includes means for generating a waveform that, following encoding by said data encoding means, contains a signal component whose frequency is a submultiple of the information bit presentation rate in accordance with the requirements of said preamble modification means.
Claim 18
Independent Claim
28 words
A system in accordance with any of claims 12 to 14 wherein said means for generating a preamble generates a modified preamble by generating the bit pattern "...011011011011..."
Claim 19
Dependent Claim
42 words
A system in accordance with claim 15 further including means for generating a two-state binary signal the state of which indicates whether the signal flowing from the detector portion of said modified preamble detection means is above or below a predetermined reference.
Claim 20
Dependent Claim
37 words
A system in accordance with claim 15 or 16 further including analog-to-digital conversion means for presenting a digital value systematically related to the magnitude of the output of the detector portion of said modified preamble detection means.
Claim 21
Dependent Claim
110 words
Apparatus for synchronizing the playback of information from a record medium transport comprising: means for extracting a playback signal from the record medium; a playback signal processing unit into which said playback signal is fed for extracting useful information from said signal; pattern detection means into which said playback signal is fed for providing an indication whenever a predetermined pattern is presented in said signal; a time reference; comparison means for indicating whether said indication is properly synchronized with said time reference; and means controlled by said comparison means for adjusting the playback speed of said record medium transport to achieve playback synchronization between said indication and said time reference.
Claim 22
Dependent Claim
110 words
Apparatus for synchronizing the playback of information from a record medium transport comprising: means for extracting a playback signal from the record medium; a playback signal processing unit into which said playback signal is fed for extracting useful information from said signal; pattern detection means into which said playback signal is fed for providing an indication whenever a predetermined pattern is presented in said signal; a time reference; comparison means for indicating whether said indication is properly synchronized with said time reference; and means controlled by said comparison means for adjusting the playback speed of said record medium transport to achieve playback synchronization between said indication and said time reference.
Claim 23
Dependent Claim
49 words
Apparatus in accordance with claim 18 which further including means for extracting a control signal from the record medium; and means responsive to said control signal for adjusting the playback speed of said record medium transports to achieve coarse synchronization adjustment of said record medium and said time reference.
Claim 24
Dependent Claim
47 words
Apparatus in accordance with claim 18 or 19 wherein the playback signal presents sectors preceded by synchronizing signals, in which said predetermined pattern provides a form of synchronizing signal that precedes selected sectors, and in which said playback signal processing unit extracts useful information from said sectors.
Claim 25
Dependent Claim
51 words
Apparatus in accordance with any of claims 18 to 20 wherein said predetermined pattern comprises a preamble that contains a frequency component at a submultiple of the bit presentation rate of the playback signal, and wherein said pattern detection means includes a circuit selectively responsive to the frequency of said component.
Claim 26
Dependent Claim
117 words
Apparatus for synchronizing the playback of information from a record medium transport having a playback head tracking adjustment mechanism comprising: means for extracting a playback signal from the record medium; a playback signal processing unit into which said playback signal is fed for extracting useful information from said playback signal; pattern detection means into which said playback signal is fed for providing an indication of the magnitude of a component of a predetermined pattern in said playback signal whenever the predetermined pattern is present in said playback signal; and tracking means responsive to the strength of said pattern for adjusting the tracking of the playback head to maximize the magnitude of said component in said playback signal.
Claim 27
Dependent Claim
117 words
Apparatus for synchronizing the playback of information from a record medium transport having a playback head tracking adjustment mechanism comprising: means for extracting a playback signal from the record medium; a playback signal processing unit into which said playback signal is fed for extracting useful information from said playback signal; pattern detection means into which said playback signal is fed for providing an indication of the magnitude of a component of a predetermined pattern in said playback signal whenever the predetermined pattern is present in said playback signal; and tracking means responsive to the strength of said pattern for adjusting the tracking of the playback head to maximize the magnitude of said component in said playback signal.
Claim 28
Independent Claim
180 words
A method of digital recording wherein information is recorded digitally in predetermined sectors at a selected substantially constant bit rate on a record medium utilizing a self-clocking channel code operating at said bit rate, said information being recorded over periodic cycles each comprising a plurality of said sectors, the sectors corresponding to respective intervals of information over each periodic cycle with a predetermined one of said sectors in each cycle corresponding to a particular interval in the respective cycle, said method comprising: providing a succession of binary bits at said bit rate according to a bit pattern that provides a periodic signal upon encoding according to said channel code, the period of said periodic signal being a multiple of the bit period; appending said periodic signal to the information in each of said predetermined ones of said sectors being recorded; selectively detecting recorded signals having the frequency of said recorded periodic signal by producing detection signals corresponding thereto; and in response to said detection signals producing periodic timing signals identifying respective times in respective said periodic cycles of recorded information.
Claim 29
Independent Claim
180 words
A method of digital recording wherein information is recorded digitally in predetermined sectors at a selected substantially constant bit rate on a record medium utilizing a self-clocking channel code operating at said bit rate, said information being recorded over periodic cycles each comprising a plurality of said sectors, the sectors corresponding to respective intervals of information over each periodic cycle with a predetermined one of said sectors in each cycle corresponding to a particular interval in the respective cycle, said method comprising: providing a succession of binary bits at said bit rate according to a bit pattern that provides a periodic signal upon encoding according to said channel code, the period of said periodic signal being a multiple of the bit period; appending said periodic signal to the information in each of said predetermined ones of said sectors being recorded; selectively detecting recorded signals having the frequency of said recorded periodic signal by producing detection signals corresponding thereto; and in response to said detection signals producing periodic timing signals identifying respective times in respective said periodic cycles of recorded information.
Claim 30
Dependent Claim
29 words
A method according to claim 23 wherein said periodic signal is appended as a preamble to the information being recorded in each of said predetermined ones of said sectors.
Claim 31
Dependent Claim
40 words
A method according to claim 23 wherein the information is played back using a playback head, said method further comprising controlling the relative positions of the record medium and the playback head to maximize the magnitude of said detection signals.
Claim 32
Dependent Claim
31 words
A method according to claim 23 further comprising providing a timing reference signal, and driving the record medium at a rate synchronizing said periodic timing signals and said timing reference signal.
Claim 33
Independent Claim
80 words
A method for processing information which is packaged into sectors and includes a time base reference including the steps of: preparing distinctive sector preambles for sectors containing particular time base reference information, said sector preambles being distinguished by unique periodic frequency components; using said sector preambles to in reading information from said sectors; and using said unique periodic frequency components to distinguish sectors containing particular time base reference information from other sectors without reference to information within the respective sectors.
Claim 34
Independent Claim
80 words
A method for processing information which is packaged into sectors and includes a time base reference including the steps of: preparing distinctive sector preambles for sectors containing particular time base reference information, said sector preambles being distinguished by unique periodic frequency components; using said sector preambles to in reading information from said sectors; and using said unique periodic frequency components to distinguish sectors containing particular time base reference information from other sectors without reference to information within the respective sectors.
Claim 35
Dependent Claim
56 words
A method in accordance with claim 27 wherein the step of preparing distinctive sector preambles involves appending to each sector a repetitive digital information pattern that repeats itself at a submultiple of the basic information bit presentation rate, a different submultiple being utilized for sectors containing particular time base reference information than utilized for other sectors.
Claim 36
Independent Claim
105 words
A method for processing information packaged into encoded sectors which information includes a time base reference including the steps of: preparing distinctive sector preambles for sectors containing particular time base reference information, said sector preambles being distinguished by unique periodic frequency components after the preamble and sector information is encoded according to said predetermined code; encoding the preamble and sector information according to said predetermined code; using said sector preambles in reading information from the sectors; and using said unique periodic frequency components to distinguish sectors containing particular time base reference information from other sectors without having to decode the information within the respective sectors.
Claim 37
Independent Claim
105 words
A method for processing information packaged into encoded sectors which information includes a time base reference including the steps of: preparing distinctive sector preambles for sectors containing particular time base reference information, said sector preambles being distinguished by unique periodic frequency components after the preamble and sector information is encoded according to said predetermined code; encoding the preamble and sector information according to said predetermined code; using said sector preambles in reading information from the sectors; and using said unique periodic frequency components to distinguish sectors containing particular time base reference information from other sectors without having to decode the information within the respective sectors.
Claim 38
Dependent Claim
16 words
A method in accordance with claim 29 wherein the predetermined code is the Miller Channel Code.
Claim 39
Dependent Claim
19 words
A method in accordance with claim 30 wherein the preamble information normally prepared for sectors contains the information "...01010101..."
Claim 40
Dependent Claim
24 words
A method in accordance with claim 31 wherein the preamble information prepared for sectors containing particular time base reference information contains the information "...011011011011..."
References Cited (Backward Citations)
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