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3M employee and church chorister Art Fry needed something to temporarily mark pages in his hymnal. He was in luck because his colleague, Spencer Silver, accidentally developed a glue that was too weak for other purposes. After initially discouraging consumer response, Post-it Notes became a hit in 1979.
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| Number | Title | Issue Date |
| 5091872 | Apparatus and method for performing spike analysis in a logic simulator A logic circuit simulator for detecting a spike condition at the output of a simulated gate. A plurality of autonomous devices are arranged for parallel pipeline operation. Each device is designed to perform only a part of the overall simulation function.... | 02/25/1992 |
| 5047971 | Circuit simulation A method of simulating the operation of a circuit utilizing voltage or current data obtained from measurements of actual samples of each of the circuit components. The actually measured voltage or current data is employed to mathematically analyze operati... | 09/10/1991 |
| 5047970 | Apparatus for displaying simulation result A result of simulation for an object circuit is displayed as a circuit diagram in which respective elements in the object circuit are colored according to the simulation result so that the simulation result can be easily understood. The elements displayed... | 09/10/1991 |
| 5025402 | Method of transient simulation of transmission line networks using a circuit simulator The disclosure is a technique to describe a complex coupled multi-port transmission line system in terms of a time-domain Green's function and then implement this description into a circuit simulator. This permits highly accurate simulation of arbitrary t... | 06/18/1991 |
| 5016204 | Expert system for performing diagnostic and redesign operations incorporating multiple levels of simulation detail An expert system for performing a redesign operation in connection with an original design. A working memory includes a plurality of blackboards each for storing a design representation and desired operational characteristics. A simulation component compr... | 05/14/1991 |
| 4939681 | Circuit simulation method for semiconductor device including field effect transistors A circuit simulation method and apparatus for simulating the operation of semiconductor devices, including field effect transistors (FETs), on the basis of the mask layout pattern of each semiconductor device. A circuit simulation method is performed by a... | 07/03/1990 |
| 4937827 | Circuit verification accessory A hardware modeling system 10 simulates portions of electrical circuits 16, 18 utilizing actual hardware components in the simulation. Access to these hardware modeling elements 16, 18 is provided on a shared basis to plural workstations 14. Simulation ve... | 06/26/1990 |
| 4937765 | Method and apparatus for estimating fault coverage Method and apparatus estimates fault coverage of a set of test vectors to be applied to a circuit containing sequential elements. The apparatus permits sequential elements to be represented as functional blocks rather than combinational circuits with feed... | 06/26/1990 |
| 4907180 | Hardware switch level simulator for MOS circuits A hardware switch level simulator for LSI/VLSI MOS circuits capable of simulating circuits with pass transistors and performing timing analysis. The simulator has a stack memory containing lists of nodes to be operated on, a solve unit having programmed l... | 03/06/1990 |
| 4899273 | Circuit simulation method with clock event suppression for debugging LSI circuits A computer implemented logic simulation method, for inspecting logical operations of large scale logic circuits, computes a variation of an output of at least one latch in a clock synchronized logic circuit. The clock-synchronized logic circuit contains a... | 02/06/1990 |
| 4868825 | Method for simulating an open fault in a logic circuit comprising field effect transistors and simulation models for implementing the method A method for simulating an open fault in a logic circuit comprising field effect transistors utilizes a simulation model which is employed and which takes the fault condition signal storage into consideration by way of an output stage. Given the appearanc... | 09/19/1989 |
| 4868770 | Simulation results enhancement method and system Simulation results enhancement software method and system are disclosed. A partial simulation results data base that is produced by an interactive simulator is software enhanced, using full elemental characterizations from the modeling subsystem thereof, ... | 09/19/1989 |
| 4862347 | System for simulating memory arrays in a logic simulation machine A method and apparatus for simulating memory devices in a logic simulation machine include a finite state machine (FSM) having input/output (I/O) sources, instruction storage resources, a real memory resource, and instruction execution resources. A plural... | 08/29/1989 |
| 4862399 | Method for generating efficient testsets for a class of digital circuits A digital logic circuit is broken into functional blocks, each having a path from its output port to a chip level output port. No two input patterns to that path produce the same output pattern on that path and for every path input pattern there is a one-... | 08/29/1989 |
| 4852093 | Method for simulating a fault in a logic circuit and a simulation model for the implementation of the method A method for simulating an erroneously-delayed signal switching at the output of the logic circuit utilizing a modified simulation model which is inherently suited for the simulation of a stuck-open fault and which, in particular, comprises an output stag... | 07/25/1989 |
| 4827427 | Instantaneous incremental compiler for producing logic circuit designs A computer aided logic design system for instantaneously compiling circuit component entries into a schematic model which provides immediate simulation of each entry or deletion into the electronic circuit schematic. The system includes software for proce... | 05/02/1989 |
| 4792913 | Simulator for systems having analog and digital portions An apparatus for simulating, in an engineering workstation (EW) environment, the operation of circuits or systems having analog and digital portions. Information concerning the system or circuit is acquired with input devices such as a keyboard or mouse w... | 12/20/1988 |
| 4791593 | System for the simulation of an electronic circuit A simulation system of an electronic circuit. The system comprises a memory, a processor, an interface circuit and data, address and control buses connecting these components. The memory has a first zone containing data for representing the simulated elec... | 12/13/1988 |
| 4787061 | Dual delay mode pipelined logic simulator Logic simulation is performed using special purpose hardware which operates in either one of two simulation modes. The machine allows detailed timing simulation where each device may be programmed with a delay time of zero, one, or multiple simulation tim... | 11/22/1988 |
| 4758947 | List processing method and apparatus Disclosed is a slave processor (100) for a multiprocessor logic circuit fault simulator. The slave processor has a hardware-based list processor (110) for performing set algebra operations on fault lists (300). The operation of the list processor centers ... | 07/19/1988 |
| 4744084 | Hardware modeling system and method for simulating portions of electrical circuits A hardware modeling system 10 simulates portions of electrical circuits 16, 18 utilizing actual hardware components in the simulation. Access to these hardware modeling elements 16, 18 is provided on a shared basis to plural workstations 14. Simulation ve... | 05/10/1988 |
| 4727545 | Method and apparatus for isolating faults in a digital logic circuit The method and apparatus for isolating faults in circuitry of a digital computer includes the use of a fault isolation generation program which provides a data base containing a list of possible faulty components for each cycle of the computer's clock for... | 02/23/1988 |
| 4725971 | Digital system simulation method and apparatus A digital system simulation apparatus and method enable a user to interactively control, during simulation, the sampling of signals in the digital system whose behavior is being simulated. The behavior of the system can be approximated better by recognizi... | 02/16/1988 |
| 4725970 | Simulation device A simulator for simulating the response of a network of predefined processing elements to a set of input stimuli. The network processing elements are arrayed in a plurality of rows and columns and a representation of each element is stored in a storage lo... | 02/16/1988 |
| 4715035 | Method for the simulation of an error in a logic circuit and a circuit arrangement for implementation of the method A method for the simulation of an error in a logic circuit which comprises a bus optionally connectible to different logic levels, utilizes the assistance of input bit patterns from which output bit patterns are derived via a simulation model containing t... | 12/22/1987 |
| 4694411 | Simulation apparatus and method A method and apparatus for simulating a network comprising a plurality of processing elements useful in simulating, for example, complex digital combinatorial electronic logic circuits. Each type of digital logic element is assigned a symbol, and the symb... | 09/15/1987 |
| 4644487 | Method and apparatus for verifying the design of digital electronic components A method for verifying the design of a digital electronic component in which the component is replaced by a simulation unit connected to the intended host system. The simulation unit has a memory for holding responses to stimuli from the host system. If t... | 02/17/1987 |
| 4635218 | Method for simulating system operation of static and dynamic circuit devices In a circuit system simulation model which may comprise a combination of physical dynamic circuit devices to be modeled, of physical static circuit devices to be modeled, and of means for controlling at least the operating sequence of the physical devices... | 01/06/1987 |
| 4628471 | Digital system simulation method and apparatus having two signal-level modes of operation A digital system simulation apparatus and method enable better efficiency and precision of system simulation by operating in either a four signal-level mode or a nine signal-level mode, depending upon the particular circuitry being employed. All signal ou... | 12/09/1986 |
| 4587625 | Processor for simulating digital structures A hardware simulator for simulating digital structures includes a general purpose computer and an improved simulator processor. The improved processor handles an advanced primitive having four inputs and one output and which is capable of representing a m... | 05/06/1986 |
| 4509132 | Method and apparatus for transfer function simulator for testing complex systems A method and apparatus for testing the operation of a complex stabilization circuit in a closed-loop system (12, 38) is comprised of a programmed analog (60-72) or digital (80-86) computing system for implementing the transfer function of a load (12), the... | 04/02/1985 |
| 4342093 | Method of digital logic simulation A logic simulation is executed using a real circuit as a part of a simulation model of a logic circuit subjected to the logic simulation. The simulation model is formed of the real circuit and a simulation circuit, and the operation of the real circuit an... | 07/27/1982 |
| 4259077 | Wireless logic trainer A wireless training device is disclosed which uses a digital computer to simulate or imitate electronic circuits, especially logic or computer circuits. Basically, a control program is selected by insertion of an edge encoded card. This card has on it a d... | 03/31/1981 |
| 3961250 | Logic network test system with simulator oriented fault test generator Disclosed is a technique for testing highly complex, functional logic where long sequences of test patterns are needed. A logic network to be tested comprises a large number of logic blocks. The inputs to several of these logic blocks are also the primary... | 06/01/1976 |
