US3643171A - Core memory delta noise cancellation - Google Patents

Core memory delta noise cancellation Download PDF

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Publication number
US3643171A
US3643171A US87541A US3643171DA US3643171A US 3643171 A US3643171 A US 3643171A US 87541 A US87541 A US 87541A US 3643171D A US3643171D A US 3643171DA US 3643171 A US3643171 A US 3643171A
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delta noise
noise cancellation
delta
function
core memory
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US87541A
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Hua-Shan Chang
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Lockheed Corp
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Lockheed Aircraft Corp
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
    • G11C11/06—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using single-aperture storage elements, e.g. ring core; using multi-aperture plates in which each individual aperture forms a storage element
    • G11C11/06007—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using single-aperture storage elements, e.g. ring core; using multi-aperture plates in which each individual aperture forms a storage element using a single aperture or single magnetic closed circuit

Definitions

  • This invention relates to noise cancellation and more particularly to delta noise cancellation to improve the core memory access time.
  • Another object of the invention is to improve the memory access time.
  • FIG. I is a block diagram of one embodiment of the invention.
  • FIG. 2 is a schematic showing a typical implementation of FIG. I;
  • FIG. 3 is a block diagram of a second embodiment of the invention.
  • FIG. 4 is a schematic showing a typical implementation of FIG. 3.
  • the present invention utilizes the characteristics of the approximated decay function to cancel or substantially reduce the delta noise.
  • FIG. I a block diagram of this method is shown. This embodiment utilizes the distinctive characteristic of the delta noise decay function /(t+1)". Observe that the product of its derivative and a ramp function is the original function. Thus, the block diagram represents the following equation:
  • the core turnover signal which is represented by Sinw I, will be partially differentiated in the output.
  • FIG. 2 represents a typical schematic to implement the block diagram of FIG. 1.
  • the input signal is differentiated by the RC network and then multip red with the ramp function by means of the transistor circuits QrQz.
  • Q converts the ramp voltage to ramp current.
  • the result is then added by QrQ Their emitter resistors RE determine the gain of the circuit.
  • the resistors RE are connected to a constant current source.
  • FIG. 3 shows a block diagram for this embodiment. Again, the delta noise decays exponentially. This circuit will implement the following equation:
  • the differentiator 5 provides the differential and the summing circuit 6 combines the output with the original signal from the gain circuit 7.
  • FIG. 4 is a typical schematic for implementing the block diagram of FIG. 3.
  • the input signal is differentiated by the RC network.
  • the differentiated output is applied to the bases Q, and Q
  • the emitter degeneration resistors RE determine the gain of the differentiator circuit.
  • the input signal is simultaneously applied to Q and Q with their emitter degeneration resistors RE determining the gain of the circuit.
  • the overall circuit is similar to FIG. 2 with the multipliers ramp input current source replaced (Q of FIG. 2) by a constant current source 8.

Abstract

Method and means for delta noise cancellation for memory systems in which the delta noise decay function is combined electronically with a separately generated function derived from the delta noise decay function to cancel or reduce the delta noise amplitude in the decaying period to improve memory access time.

Description

United States Patent [151 3,643,171
Chang 1451 Feb. 15, 1972 [54] CORE MEMORY DELTA NOISE 3,387,221 6/1968 Arberman et al ..328/163 CANCELLATION 3,094,665 6/1963 Wildman ..328/165 [72] Inventor: Hua-Shan Chang, South Pasadena, Calif. ()TH ER PUBLICATIONS [73] Asslgnee: ggg Alrcra Corporation Burbank Adaptive FSK Data Demodulator" by R. W. Calfee. lBM Technical Disclosure Bulletin,Vol. 5,No. LApr. 1963.p. 76 [22] Filed: Nov. 6, 1970 (Copy in 328/1 16) 21 A LN 87 41 1 pp 0 ,5 Primary ExaminerDonald D. Forrer Assistant Examiner-Harold A. Dixon [52] US. Cl. ..328/l65, 328/1 17, 307/231 mmmey (;eorge C Sullivan [51] Int. Cl. ..H04b 1/12 [58] Field ofSearch ..330/69; 307/231; 328/116, 1 17, TR!
328/165, 163 [57] ABS CT Method and means for delta noise cancellation for memory [56] References Cited systems in which the delta noise decay function is combined electronically with a separately generated function derived 1 UNTED STATES PATENTS from the delta noise decay function to cancel or reduce the 2,450,818 10/1948 Vermillion ..325/467 delta noise amplitude in the decaying period to improve 3,328,704 6/1967 Wantland ..328/1l7 memory access time- 2,534,264 12/1950 Hoeppner ..328/117 3,119,070 1/1964 Seliger .323/114 1 cla'ms4maw'ng V in (t) V owreneurmros mumeuen SUM V out GAIN V in ('r) SHEET 1 OF 2 0| FFERENTIATOR GAIN FIG.
Romp inpui MULTIPLIER sum Voui l I RE i Ccmstont I \,Q5
INVENTOR.
HUA-SHAN CHANG Agent Vou? PMENTEDFEB 15 ran SHEET 2 OF 2 V out (i) SUM DIFFERENTIATOR GAIN Vin (t) FIG. 3
V out l Conston? I RE2 INVENTOR. HUA-SHAN CHANG Agent CORE MEMORY DELTA NOISE CANCELLATION This invention relates to noise cancellation and more particularly to delta noise cancellation to improve the core memory access time.
The inherent limitation on the access time of a large core memory usually lies in the slow decay of the delta noise in the sense lines. Normally, the delta noise decays according to an exponential function if the line is properly terminated. Previous attempts to differentiate the decay function with the hope that it will reduce to zero faster and be more predictable have been unsuccessful.
It is therefore an object of the present invention to provide an improved method for cancellation or reducing the delta noise amplitude.
Another object of the invention is to improve the memory access time.
These and other objects of the invention will become more apparent from the following description when taken with the accompanying drawings in which:
FIG. I is a block diagram of one embodiment of the invention;
FIG. 2 is a schematic showing a typical implementation of FIG. I;
FIG. 3 is a block diagram of a second embodiment of the invention;
FIG. 4 is a schematic showing a typical implementation of FIG. 3.
The sense line in a memory system may be compared to a transmission line with the cores evenly spaced on the line. Analysis shows that after the current has reached the threshold of the minor wall displacement (on the hysteresis loop), the delta noise waveform follows the equation a-b exp(t) up to !=T, where Tis the total delay of the sense line. If the line is properly terminated, the delta noise will then decay exponentially. Otherwise, the decay of the delta noise can be approximated by the function /(t+l where n can be determined from the length of the sense line and the reflection coefficient of the termination. The present invention utilizes the characteristics of the approximated decay function to cancel or substantially reduce the delta noise.
DIFFERENTIATION MULTIPLICATION Referring to FIG. I, a block diagram of this method is shown. This embodiment utilizes the distinctive characteristic of the delta noise decay function /(t+1)". Observe that the product of its derivative and a ramp function is the original function. Thus, the block diagram represents the following equation:
Vout (t) Vin (t) 1) Substituting in equation (1), we have:
can
from which it is readily observed that the output is zero. The core turnover signal, which is represented by Sinw I, will be partially differentiated in the output.
FIG. 2 represents a typical schematic to implement the block diagram of FIG. 1. The input signal is differentiated by the RC network and then multip red with the ramp function by means of the transistor circuits QrQz. Q converts the ramp voltage to ramp current. The result is then added by QrQ Their emitter resistors RE determine the gain of the circuit. The resistors RE are connected to a constant current source. For the delta noise to be cancelled properly, the following Where K T/q= mv. at room temperature The condition to cancel the delta noise is l,'=I which 0 gives the following equation:
so? v V, w I
comprising an nput signal including a delta noise s gnal.
5% anRC q Differentiation-Add FIG. 3 shows a block diagram for this embodiment. Again, the delta noise decays exponentially. This circuit will implement the following equation:
The noiseis represented by exp (t) and Vin(t) exp In FIG. 3, the differentiator 5 provides the differential and the summing circuit 6 combines the output with the original signal from the gain circuit 7.
FIG. 4 is a typical schematic for implementing the block diagram of FIG. 3.
The input signal is differentiated by the RC network. The differentiated output is applied to the bases Q, and Q The emitter degeneration resistors RE determine the gain of the differentiator circuit. The input signal is simultaneously applied to Q and Q with their emitter degeneration resistors RE determining the gain of the circuit. The overall circuit is similar to FIG. 2 with the multipliers ramp input current source replaced (Q of FIG. 2) by a constant current source 8.
For the circuit to function properly, the following equation should be satisfied:
RC=REIIRE2 What is claimed is: 1. Means for delta noise cancellation for memory systems means for differentiating said input signal, multiplier means for multiplying the differentiated signal and a ramp function, a summing amplifier, means for applying the output of said mul tiplier means to said amplifier and means for applying the input signal to said amplifier.
i IR

Claims (1)

1. Means for delta noise cancellation for memory systems comprising an input signal including a delta noise signal, means for differentiating said input signal, multiplier means for multiplying the differentiated signal and a ramp function, a summing amplifier, means for applying the output of said multiplier means to said amplifier and means for applying the input signal to said amplifier.
US87541A 1970-11-06 1970-11-06 Core memory delta noise cancellation Expired - Lifetime US3643171A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3946211A (en) * 1974-07-17 1976-03-23 Leeds & Northrup Company Amplitude limited filter
US4094723A (en) * 1976-04-12 1978-06-13 J & H Manufacturing, Inc. Variable width film splicer
US4920279A (en) * 1987-10-06 1990-04-24 Sgs Thomson Microelectronics Sa Method to expand an analog signal and device to implement the method

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2450818A (en) * 1944-08-26 1948-10-05 Raymond K Vermillion Electronic noise eliminator
US2534264A (en) * 1945-08-03 1950-12-19 Conrad H Hoeppner Pulse width discriminator
US3094665A (en) * 1959-04-27 1963-06-18 Raytheon Co Means for the detection of signals in the presence of noise
US3119070A (en) * 1961-10-10 1964-01-21 Sperry Rand Corp Ford Instr Co Signal derivative detection device
US3328704A (en) * 1964-03-10 1967-06-27 Western Electric Co Pulse peak detector
US3387221A (en) * 1966-02-09 1968-06-04 Navy Usa Pulse discriminator with noise suppression

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2450818A (en) * 1944-08-26 1948-10-05 Raymond K Vermillion Electronic noise eliminator
US2534264A (en) * 1945-08-03 1950-12-19 Conrad H Hoeppner Pulse width discriminator
US3094665A (en) * 1959-04-27 1963-06-18 Raytheon Co Means for the detection of signals in the presence of noise
US3119070A (en) * 1961-10-10 1964-01-21 Sperry Rand Corp Ford Instr Co Signal derivative detection device
US3328704A (en) * 1964-03-10 1967-06-27 Western Electric Co Pulse peak detector
US3387221A (en) * 1966-02-09 1968-06-04 Navy Usa Pulse discriminator with noise suppression

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Adaptive FSK Data Demodulator by R. W. Calfee IBM Technical Disclosure Bulletin Vol. 5 No. 11 Apr. 1963 p. 76. *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3946211A (en) * 1974-07-17 1976-03-23 Leeds & Northrup Company Amplitude limited filter
US4094723A (en) * 1976-04-12 1978-06-13 J & H Manufacturing, Inc. Variable width film splicer
US4920279A (en) * 1987-10-06 1990-04-24 Sgs Thomson Microelectronics Sa Method to expand an analog signal and device to implement the method

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