Patent US3720929A successfully refreshed from Google Patents.
US3720929A
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Magnetic core memories
Assignee: EMI Group Ltd
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Filing: 1971-03-19
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Granted: 1973-03-13
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Expires: 1991-03-19
Abstract
Abstract In a magnetic core memory non-destructive read-out is achieved by a read pulse of insufficient amplitude to reset the core to the O state while of sufficient amplitude to induce a significant output for a core in the 1 state, which is preferably not fully saturated. Digital information read out from a matrix memory can be amplitude modulated by varying the amplitude of the read pulses. The memory can be used to control a stage lighting system, the amplitude modulation controlling fades and crossfades.
Inventors
- 👤 R Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:08
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/02; G11C11/06; G11C11/06007; G11C11/06014; G11C11/0605; G11C11/06057; G11C11/06071; H; H05; H05B; H05B47/00; H05B47/10; H05B47/155
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
235 words
A magnetic core memory comprising a plurality of cores arranged in a matrix wherein a plurality of groups of cores correspond to words of information, a write circuit coupled to the cores for selectively setting each core to a first state in which the remanent flux circulates in one sense and is not substantially less than the saturation flux and a second state in which the remanent flux circulates in the other sense and is less than the saturation flux, at least one sense winding, each of which links at least one core from each group, a plurality of read conductors linking the cores of the said groups respectively, a read circuit coupled to the matrix by way of the read conductors, the read circuit being adapted to furnish a continuing succession of read pulses in any selected read conductor for generating a correspondingly continuing signal in the sense windings of cores in the second state, which pulses are of the sense tending to switch a core from the second state to the first state but are of insufficient magnitude actually to switch a core and induce a substantially greater pulse in a sense winding when a core is in the second state than when a core is in the first state, and means for varying the amplitude of the read pulses, thereby to amplitude-modulate the digital information read out from a group of cores.
Claim 2
Dependent Claim
235 words
A magnetic core memory comprising a plurality of cores arranged in a matrix wherein a plurality of groups of cores correspond to words of information, a write circuit coupled to the cores for selectively setting each core to a first state in which the remanent flux circulates in one sense and is not substantially less than the saturation flux and a second state in which the remanent flux circulates in the other sense and is less than the saturation flux, at least one sense winding, each of which links at least one core from each group, a plurality of read conductors linking the cores of the said groups respectively, a read circuit coupled to the matrix by way of the read conductors, the read circuit being adapted to furnish a continuing succession of read pulses in any selected read conductor for generating a correspondingly continuing signal in the sense windings of cores in the second state, which pulses are of the sense tending to switch a core from the second state to the first state but are of insufficient magnitude actually to switch a core and induce a substantially greater pulse in a sense winding when a core is in the second state than when a core is in the first state, and means for varying the amplitude of the read pulses, thereby to amplitude-modulate the digital information read out from a group of cores.
Claim 3
Dependent Claim
235 words
A magnetic core memory comprising a plurality of cores arranged in a matrix wherein a plurality of groups of cores correspond to words of information, a write circuit coupled to the cores for selectively setting each core to a first state in which the remanent flux circulates in one sense and is not substantially less than the saturation flux and a second state in which the remanent flux circulates in the other sense and is less than the saturation flux, at least one sense winding, each of which links at least one core from each group, a plurality of read conductors linking the cores of the said groups respectively, a read circuit coupled to the matrix by way of the read conductors, the read circuit being adapted to furnish a continuing succession of read pulses in any selected read conductor for generating a correspondingly continuing signal in the sense windings of cores in the second state, which pulses are of the sense tending to switch a core from the second state to the first state but are of insufficient magnitude actually to switch a core and induce a substantially greater pulse in a sense winding when a core is in the second state than when a core is in the first state, and means for varying the amplitude of the read pulses, thereby to amplitude-modulate the digital information read out from a group of cores.
Claim 4
Dependent Claim
235 words
A magnetic core memory comprising a plurality of cores arranged in a matrix wherein a plurality of groups of cores correspond to words of information, a write circuit coupled to the cores for selectively setting each core to a first state in which the remanent flux circulates in one sense and is not substantially less than the saturation flux and a second state in which the remanent flux circulates in the other sense and is less than the saturation flux, at least one sense winding, each of which links at least one core from each group, a plurality of read conductors linking the cores of the said groups respectively, a read circuit coupled to the matrix by way of the read conductors, the read circuit being adapted to furnish a continuing succession of read pulses in any selected read conductor for generating a correspondingly continuing signal in the sense windings of cores in the second state, which pulses are of the sense tending to switch a core from the second state to the first state but are of insufficient magnitude actually to switch a core and induce a substantially greater pulse in a sense winding when a core is in the second state than when a core is in the first state, and means for varying the amplitude of the read pulses, thereby to amplitude-modulate the digital information read out from a group of cores.
Claim 5
Dependent Claim
37 words
A magnetic core memory according to claim 1, comprising means for reducing the amplitude of the read pulses applied to one selected group while simultaneously increasing the amplitude of the read pulses applied to another selected group.
Claim 6
Dependent Claim
57 words
A magnetic core memory according to claim 1, wherein the cores in each group are divided into a plurality of sets, the cores in each set being linked by the same sense winding individual to the set and the read circuit being adapted to apply read pulses of different amplitudes simultaneously to all cores in a set.
Claim 7
Dependent Claim
21 words
A magnetic core memory according to claim 3, wherein the relative values of the said different amplitudes form a binary progression.
Claim 8
Dependent Claim
22 words
A magnetic core memory according to claim 1, wherein the remanent flux in the second state corresponds to the ''''read disturbed'''' flux.
Claim 9
Dependent Claim
59 words
A magnetic core memory according to claim 1, wherein the second state is established by a write waveform comprising a current pulse of sufficient amplitude to substantially saturate the core with the flux circulating in the said other sense, followed by a current pulse of opposite polarity and smaller amplitude, insufficient to switch the core to the first state.
Claim 10
Dependent Claim
68 words
A magnetic core memory according to claim 1, comprising a further core maintained in the first state and to which a read current pulse is applied when such a pulse is applied to a group of the first mentioned cores, and means for subtracting the signal induced in the sense winding of the further core from the signal induced in the sense windings of the group of cores.
Claim 11
Dependent Claim
20 words
A magnetic core memory according to claim 1, wherein the succession of read pulses is a half-wave rectified a.c. signal.
Claim 12
Dependent Claim
40 words
A lighting control system comprising a magnetic core memory according to claim 1, and a plurality of intensity control circuits for corresponding lights or banks of lights, each such circuit being responsive to a corresponding sense winding of the memory.
Claim 13
Dependent Claim
41 words
A magnetic core memory according to claim 1, wherein the second state is established by a write pulse of sufficient amplitude to substantially saturate the core with the flux circulating in the said other sense, followed by a read current pulse.
Claim 14
Dependent Claim
192 words
A lighting control system comprising a plurality of intensity control circuits for controlling lights or banks of lights, a matrix of square loop cores arranged in groups corresponding to different lighting settings, a write circuit for selectively setting each core individually to a first state in which the remanent flux circulates in one sense and is not substantially less than the saturation flux and a second state in which the remanent flux circulates in the other sense, a plurality of sense windings each of which links at least one core from each group and is coupled to a corresponding intensity control circuit for supplying a pulsating control signal thereto, a read circuit coupled to each group of cores for applying a pulsating read signal to all the cores of any selected group, and means for varying the amplitude of the pulses of the read signal up to an upper limit for correspondingly varying the amplitude of each pulsating control signal induced in a sense winding, and pulses tending to switch the cores from the second state to the first state and said upper amplitude limit being insufficient actually to switch the core.
Claim 15
Dependent Claim
192 words
A lighting control system comprising a plurality of intensity control circuits for controlling lights or banks of lights, a matrix of square loop cores arranged in groups corresponding to different lighting settings, a write circuit for selectively setting each core individually to a first state in which the remanent flux circulates in one sense and is not substantially less than the saturation flux and a second state in which the remanent flux circulates in the other sense, a plurality of sense windings each of which links at least one core from each group and is coupled to a corresponding intensity control circuit for supplying a pulsating control signal thereto, a read circuit coupled to each group of cores for applying a pulsating read signal to all the cores of any selected group, and means for varying the amplitude of the pulses of the read signal up to an upper limit for correspondingly varying the amplitude of each pulsating control signal induced in a sense winding, and pulses tending to switch the cores from the second state to the first state and said upper amplitude limit being insufficient actually to switch the core.
Claim 16
Dependent Claim
60 words
A lighting control system according to claim 11, wherein the said means for varying are adapted to reduce the amplitude of the read signal applied to one group of cores while simultaneously increasing the ampliture of the read signal applied to one group of cores while simultaneously increasing the amplitude of the read signal applied to another group of cores.
Claim 17
Dependent Claim
59 words
A lighting control system according to claim 11, wherein the cores in each group are divided into a plurality of sets, the cores in any set being linked by the same sense winding, and the read circuit being adapted to apply read signals of different amplitudes not exceeding the said upper limit simultaneously to all cores in a set.
References Cited (Backward Citations)
US3321749A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |