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Mixed Mode Modelling and Simulation, IEE Colloquium on

Date 1994

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  • Modelling in VHDL-A

    Page(s): 3/1 - 3/4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    VHDL (IEEE Standard 1076) is currently being extended to include mixed-signal and analogue modelling (VHDL-A). A draft standard is expected in 1995. This paper describes two models developed in VHDL-A. One of the design objectives of VHDL-A is compatibility with SPICE, and, therefore, a version of the SPICE Level 3 MOS model has been written. The second model is of a phase-locked loop, including a VCO. As the standard is not complete, no VHDL-A simulators are available to verify these models. Nevertheless, it has been possible to investigate several important aspects of modelling with VHDL-A View full abstract»

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  • Behavioural level mixed A/D system exploration

    Page(s): 2/1 - 2/5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (220 KB)  

    Systems designers are constantly in need of different ways to explore their inherent creativity while at the same time bearing in mind that they may have to implement their ideas. It is important to be able to filter valuable ideas early in the development cycle and run multiple what-if scenarios to fully evaluate the potential of a given idea. The intent of this paper is to discuss practical ways of exploring the kinds of ideas that systems designers routinely have to investigate to stay ahead of the game View full abstract»

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  • IEE Colloquium on `Mixed Mode Modelling and Simulation' (Digest No.1994/205)

    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (236 KB)  

    The following topics were dealt with: analogue behavioural modelling and simulation using VHDL and SABER-MAST; behavioural-level mixed A/D system exploration; modelling in VHDL-A; simulation of mixed mode systems with enhanced visualization using virtual reality techniques; modelling abstraction; mixed-signal simulation using the ALFA simulation backplane; parallel computing for mixed mode system simulation; extending VHDL for mixed-signal simulation; analogue fault simulation; and utilising mixed mode simulation View full abstract»

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  • Analogue fault simulation

    Page(s): 9/1 - 9/5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    Analogue testing often takes a functional approach. However, a number of structural (fault-orientated) approaches are being investigated and have been shown to have advantages such as reliability indication. One of the main problems with a structural approach is the lengthy run times for analogue fault simulation (AFS). The paper describes the use of higher level modelling of analogue functional blocks as part of a multi-level simulation in order to accelerate AFS, and assesses its impact in terms of speedup and accuracy. Software tools which have been developed to give an indication of fault coverage for analogue circuits are also described. The paper concludes that a mixed-mode approach can reduce AFS time for larger circuits without excessive loss of accuracy View full abstract»

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  • Modelling abstraction-the highs and lows of mixed mode simulation

    Page(s): 5/1 - 5/7
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (428 KB)  

    The paper focuses on the different types of mixed mode simulation that are available today and their use within the electronics design environment. It explains the benefits of verifying a design, which can be achieved by combining the high level abstraction of digital and analogue models using behavioural languages with lower levels of modelling abstractions like SPICE primitives or digital modelling languages. It focuses on the different problems that can be encountered whilst performing mixed mode simulation including the handling of digital unknowns, synchronisation between analogue and digital simulation engines and the handling of different digital technologies like CMOS and TTL. Today's electronic designers need mixed mode simulation to handle varying complexities of analogue and digital circuitry. The paper suggests different solutions, through the use of analogue versions of digital models, to `C' models of analogue components that are capable of running under a digital simulation environment View full abstract»

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  • Analogue behavioural modelling and simulation using VHDL and Saber-MAST

    Page(s): 1/1 - 1/5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    The IEEE standard 1076 VHDL (VHSIC Hardware Description Language) has been widely used as the universal medium for the exchange of designs and the simulation tool. The current version of VHDL is primarily used for digital simulations; it is not yet a mixed-mode simulator. However, it provides the capabilities of modelling analogue signals and analogue behavioural functions in addition to digital modelling. When modelling circuits behaviourally using VHDL, a suitable concurrent statement is the process statement. With the process statement, VHDL provides the facilities of a general-purpose programming language to the hardware designer. The Saber simulator (from Analogy) was initially an analogue simulator, but now it is a comprehensive mixed-mode simulator, spanning the analogue and digital domains. The Saber simulator provides a versatile modelling language called MAST which allows for easy addition of new models. Unlike SPICE, modelling can be done only at the netlist level and by using built-in models. Saber is a general-purpose simulator and can be used in a broad scope of applications. It can be applied to electrical, optical, thermal or mechanical systems or any combination of these different technologies as long as the model can be expressed in the form of algebraic and differential equations using MAST View full abstract»

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  • Mixed-signal simulation using the Alfa simulation backplane

    Page(s): 6/1 - 6/3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    While specialised, integrated mixed-signal simulators have been successfully developed, they cannot, in general, be extended easily to include further simulation algorithms. The concept of a simulation backplane has been proposed in which any number of general simulators can be coupled to allow a wide range of mixed-signal, mixed-level simulations to be performed. A standard set of programming interfaces has been proposed to allow simulators to be coupled in a standard way. The paper describes a simulation backplane that has been developed, together with basic circuit and logic-level simulators. In order to allow true mixed-signal simulations to be performed, Spice version 3e2 has been coupled into the backplane View full abstract»

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  • Utilizing mixed mode simulation

    Page(s): 10/1 - 10/3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (128 KB)  

    Discusses how in mixed mode simulation there is a choice of specifying accuracy or specifying performance. Increased accuracy is obtained at the cost of more CPU-time. Circuits containing analog and digital components which are too expensive to simulate in a low level simulator can be naturally simulated in mixed mode. Schematic diagrams containing different levels of abstraction can be logically captured in a mixed mode simulation to verify their operation. Also designs represented at different levels of abstraction using top down or bottom up methodology can be assimilated in mixed mode simulation. Further, technological considerations of circuits can call for mixed mode as a single mode is incapable of accommodating bidirectionality, charge sharing, pass transistors and W/L effects together. Mixed mode can incorporate physically attached devices to the simulator for the modelling of complex devices. This eliminates debugging and accelerates system simulations as interrogation of the device is at hardware speeds. Mixed mode simulation issues include which levels to include and where (partitioning), compatible signal and time representations among modes, simulator architecture and user interface View full abstract»

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  • Simulation of mixed-mode systems with enhanced visualisation using virtual reality techniques

    Page(s): 4/1 - 4/4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (204 KB)  

    Most manufacturing oriented simulation languages only offer the facility to model the system in one mode: discrete or continuous. However if a real, single mode system is examined more closely, some characteristics of the opposing mode can usually be found. It is to what extent that the opposing mode can be neglected that determines in which mode the system can be successfully modelled. For many systems it is not satisfactory to approximate to a single mode system, and a mixed-mode systems simulation language would be required. A genuine mixed-mode simulation language would be able to model both discrete and continuous systems individually, in addition to combined continuous/discrete systems, and would therefore be a more useful general purpose simulation tool. It has been postulated that all systems should be treated as mixed-mode, with those with only discrete characteristics, or those with only continuous characteristics treated only as exceptions instead of the rule View full abstract»

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  • Parallel computing for mixed-mode system simulation

    Page(s): 7/1 - 7/6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    The application of parallel processing to mixed-mode systems is discussed. A simplified version of an important application area in personal communications is used to demonstrate that simple partitioning of the overall computer task can lead to speed-ups in the simulation run times from those achieved using single processor systems. In addition, it is argued that the parallel processing approach is highly suited to mixed-mode systems due to the straightforward mapping between different elements of the problem being studied and the computing hardware View full abstract»

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