US3911488A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for synchronizing record/reproduce transports
Assignee: Ampex Corp
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Filing: 1974-04-24
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Granted: 1975-10-07
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Expires: 1994-04-24
Abstract
Abstract In the operation of magnetic tape record/reproduce transports, a system is described for synchronizing the record/reproduce rates of at least two tapes at preselected and addressable signal storage locations thereon, each tape being carried by a different transport. In particular, a forward-backward counter is employed to monitor the time or phase separation between the selected storage locations associated with each transported tape and a digital-to-analog converter responsive to such counter is arranged to advance the signal transfer rate of one of the transported tapes while simultaneously retarding the signal transfer rate of the other tape so that the desired signal storage locations approach alignment. The differential advancement and retardation of the respective transports is gradually reduced to a level at which both transports are operated at equal and standard record/reproduce rates as the selected signal locations on the respective tapes assume alignment condition.
Inventors
- 👤 Tracy G Wood
- 👤 Erik O J Salbu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:03
CPC Classifications
G; G11; G11B; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/32; G11B27/002; G11B27/02; G11B27/022; G11B27/024; G11B27/031; G11B27/032; H; H02; H02P; H02P5/00; H02P5/46; H02P5/52; H02P5/56; G11B2220/00; G11B2220/20; G11B2220/40; G11B2220/41; G11B2220/415; G11B2220/90
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
276 words
In a method of controlling the drives of a pair of transports each for moving a storage medium carrying recorded storage location signals and each having control signals associated therewith from which the rate at which its storage medium is moved can be determined wherein the transports are operated to provide the associated control signals and to reproduce the storage location signals for synchronizing the record/reproduce rates of the transports while the storage media are relatively positioned to align selected storage locations thereof, the steps comprising: establishing a reference indicative of the synchronized record/reproduce rates of the transports with the selected storage locations aligned; comparing to said established reference the control signals provided by one of the transports in response to the reproduction of storage location signals of the storage medium moved thereby; comparing to said established reference the control signals provided by the other transport in response to the reproduction of storage location signals of the storage medium moved thereby; generating a representation of the record/reproduce rates of the transports and alignment of the storage locations in response to said comparisons; commanding the transports simultaneously in response to said generated representation to cause both to move their respective storage media in accordance with said generated representation; and adjusting the commanding of the transports simultaneously in opposite phase senses when said generated representation indicates a lack of synchronization of the record/reproduce rates of the transports and alignment of selected storage locations to cause one of the transports to move its storage medium at a rate greater than the synchronized rate and the other to move its storage medium at a rate less than the synchronized rate.
Claim 2
Dependent Claim
276 words
In a method of controlling the drives of a pair of transports each for moving a storage medium carrying recorded storage location signals and each having control signals associated therewith from which the rate at which its storage medium is moved can be determined wherein the transports are operated to provide the associated control signals and to reproduce the storage location signals for synchronizing the record/reproduce rates of the transports while the storage media are relatively positioned to align selected storage locations thereof, the steps comprising: establishing a reference indicative of the synchronized record/reproduce rates of the transports with the selected storage locations aligned; comparing to said established reference the control signals provided by one of the transports in response to the reproduction of storage location signals of the storage medium moved thereby; comparing to said established reference the control signals provided by the other transport in response to the reproduction of storage location signals of the storage medium moved thereby; generating a representation of the record/reproduce rates of the transports and alignment of the storage locations in response to said comparisons; commanding the transports simultaneously in response to said generated representation to cause both to move their respective storage media in accordance with said generated representation; and adjusting the commanding of the transports simultaneously in opposite phase senses when said generated representation indicates a lack of synchronization of the record/reproduce rates of the transports and alignment of selected storage locations to cause one of the transports to move its storage medium at a rate greater than the synchronized rate and the other to move its storage medium at a rate less than the synchronized rate.
Claim 3
Dependent Claim
137 words
The method as defined in claim 1 wherein a preset signal level is established as the reference; the comparison steps include changing the preset signal level in one sense in accordance with the control signal provided by one of the transports in response to the reproduction of storage location signals of the storage medium moved thereby, and changing the preset level in the reverse sense in accordance with the control signal provided by the other transport in response to the reproduction of storage location signals of the storage medium moved thereby; the representation generating step includes generating a resultant signal level from said changes as the representation of the record/reproduce rates and alignment of storage locations, and the simultaneous commanding step includes generating drive signals for each of the transports in response to said resultant signal level.
Claim 4
Dependent Claim
209 words
The method as defined in claim 2 wherein the preset signal level is a midrange count established by a reversible pulse counter; the comparison steps include coupling to the reversible pulse counter the control signal provided by the first transport to change the counting state of the counter in one direction in response to the reproduction of storage location signals of the storage medium moved by said first transport and coupling to said counter the control signal provided by the second transport to change the counting state of the counter in an opposite direction in response to the reproduction of the storage location signals of the storage medium moved by said second transport; and the simultaneous commanding step includes detecting the instantaneous count level of said counter, and commanding said transports to transport the storage media at equal rates when said count level is within the midrange count state and to transport the storage medium of one of the transports at an advanced rate and the storage medium of the other transport at a retarded rate when said count level is to either side of said midrange count state, said advanced and retarded rates depending on the direction and magnitude of the count level relative to said midrange state.
Claim 5
Dependent Claim
40 words
The method as defined in claim 3, further comprising the step of detecting the occurrence of said midrange count state on said counter and in response thereto synchronizing the record/reproduce rates of both said transports to a reference timing signal.
Claim 6
Dependent Claim
68 words
The method as defined in claim 3 wherein said counter has a digital output and further comprising, the step of converting such digital output from said counter into an analog control signal having a magnitude and polarity representing the number of counting states and direction in which the instantaneous counting state is offset from said midrange state for controlling the record/reproduce rates of said transports in accordance therewith.
Claim 7
Dependent Claim
66 words
The method as defined in claim 5 wherein said transports each have a servo input for receiving a rate control signal and further comprising, the steps of passing said analog control signal over separate circuit paths to said transport servo inputs and inverting the phase polarity of said analog signal in one of said paths to provide for controlling the transport rates in opposite phase senses.
Claim 8
Dependent Claim
61 words
The method defined in claim 6 further comprising, the steps of developing a reference timing signal for operating both said transports at a preselected record/reproduce rate, detecting the occurrence of said midrange counting state and in response thereto interrupting said circuit paths carrying said analog control signals to said transport inputs and connecting said reference timing signal to said transport inputs.
Claim 9
Dependent Claim
55 words
The method defined in claim 1 further comprising the steps of developing a reference timing signal for controlling both of said transports to be operated at a preselected record/reproduce rate, and detecting the occurrence of synchronization between the record/reproduce rates of said transports to cause said transports to be controlled by said reference timing signal.
Claim 10
Independent Claim
321 words
A system for controlling a pair of transports each mOving a storage medium carrying recorded storage location signals thereon and each providing control signals at a rate according to the rate of transport of the medium moved thereby to simultaneously align a selected storage location of one of the media relative to a selected storage location of the other and synchronize the record/reproduce rates of the transports with the selected storage locations aligned, comprising: separate electrical signal detector means associated with each transport for detecting storage location signals reproduced from the medium moved by its associated transport; forward-backward counter means having a preselected count state serving as a reference indicative of the alignment of storage locations and synchronization of record/reproduce rates, said counter counting in a forward direction in response to pulses received at a first input and counting in a backward direction in response to pulses received at a second input; gating circuit means connecting the first input of said counter means to receive pulses derived from the control signal provided by a first of said transports in response to the detection of storage location signals by the detector means associated therewith and connecting the second input of said counter means to receive pulses derived from the control signal provided by a second of said transport in response to the detection of storage location signals by detector means associated therewith; and digital-to-analog converter means connected between said counter and both of said transports and being responsive to count states to one side of said preselected count state to advance the rate of transport of the medium by the first transport and simultaneously retard the rate of transport of the medium by the second transport and being responsive to count states to the other side of said preselected count state to retard the medium transport rate of said first transport and simultaneously advance the medium transport rate of said second transport.
Claim 11
Independent Claim
321 words
A system for controlling a pair of transports each mOving a storage medium carrying recorded storage location signals thereon and each providing control signals at a rate according to the rate of transport of the medium moved thereby to simultaneously align a selected storage location of one of the media relative to a selected storage location of the other and synchronize the record/reproduce rates of the transports with the selected storage locations aligned, comprising: separate electrical signal detector means associated with each transport for detecting storage location signals reproduced from the medium moved by its associated transport; forward-backward counter means having a preselected count state serving as a reference indicative of the alignment of storage locations and synchronization of record/reproduce rates, said counter counting in a forward direction in response to pulses received at a first input and counting in a backward direction in response to pulses received at a second input; gating circuit means connecting the first input of said counter means to receive pulses derived from the control signal provided by a first of said transports in response to the detection of storage location signals by the detector means associated therewith and connecting the second input of said counter means to receive pulses derived from the control signal provided by a second of said transport in response to the detection of storage location signals by detector means associated therewith; and digital-to-analog converter means connected between said counter and both of said transports and being responsive to count states to one side of said preselected count state to advance the rate of transport of the medium by the first transport and simultaneously retard the rate of transport of the medium by the second transport and being responsive to count states to the other side of said preselected count state to retard the medium transport rate of said first transport and simultaneously advance the medium transport rate of said second transport.
Claim 12
Dependent Claim
114 words
The system as defined in claim 9, wherein each of said transports has a rate control signal input and further comprising, a reference signal means for controlling said transports at a preselected medium transport rate, switching circuit means selectively and alternately connecting either said converter means or said reference signal means to said transport rate control signal inputs, and synchronism detector means connected to and operating said switching means in response to said counter means assuming said preselected count state to dispose said switching means in a condition connecting said reference signal means to said transport rate control signal inputs for operating said transports to move the associated media at said preselected transport rate.
Claim 13
Dependent Claim
88 words
The system as defined in claim 9, wherein said converter means has an output for connection to said transports issuing an analog signal having an amplitude and polarity representing the instantaneous count state relative to said preselected count state, and further comprising, polarity inverter means connected between said converter output and one of said transports to provide for controlling advancing the medium transport rate of one transport while simultaneously retarding the medium transport rate of the other in response to the same output signal from said converter means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |