Difference between revisions of "An Overview of System-Level Macromodeling Using Virtual Blocks"

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(Example 1: Analog Signal Differentiation)
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[[RF.Spice A/D]] provides an extensive library of black-box virtual blocks that allow you to quickly test and verify new system concepts without getting into the details of particular circuit realizations. A virtual block typically has one or more input pins and one or more output pins. A system-level function or behavior is modeled by the relationship between the input and output voltages. For example, a multiplier block takes two input voltages and outputs their product. An analog frequency doubler takes a single sinusoidal input voltage and produces a sinusoidal output voltage, whose frequency is twice as large as the input frequency.   
 
[[RF.Spice A/D]] provides an extensive library of black-box virtual blocks that allow you to quickly test and verify new system concepts without getting into the details of particular circuit realizations. A virtual block typically has one or more input pins and one or more output pins. A system-level function or behavior is modeled by the relationship between the input and output voltages. For example, a multiplier block takes two input voltages and outputs their product. An analog frequency doubler takes a single sinusoidal input voltage and produces a sinusoidal output voltage, whose frequency is twice as large as the input frequency.   
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<td> [[Image:Diff0.png|thumb|640px|A generic macromodel with input and output stages.]] </td>
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</tr>
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</table>
  
 
== Example 1: Analog Signal Differentiation ==
 
== Example 1: Analog Signal Differentiation ==

Revision as of 15:48, 18 August 2015

An Introduction to Macromodeling

RF.Spice A/D provides an extensive library of black-box virtual blocks that allow you to quickly test and verify new system concepts without getting into the details of particular circuit realizations. A virtual block typically has one or more input pins and one or more output pins. A system-level function or behavior is modeled by the relationship between the input and output voltages. For example, a multiplier block takes two input voltages and outputs their product. An analog frequency doubler takes a single sinusoidal input voltage and produces a sinusoidal output voltage, whose frequency is twice as large as the input frequency.

A generic macromodel with input and output stages.

Example 1: Analog Signal Differentiation

The simplest voltage differentiator can be made based on the basic properties of a capacitor:

[math] i(t) = C \frac{dv}{dt} [/math]

where v(t) and i(t) are the voltage and current of the capacitor and C is it capacitance. Similarly for an inductor, one can write:

[math] v(t) = L \frac{di}{dt} [/math]

where L is the inductance.

It is important to note that in virtual blocks we only care about the functional behavior, completely ignoring the practical realization of a particular circuit. In the above equations, if we set C = 1F or L = 1H (regardless of the actual physical devices), we will get a derivative relationship between the voltage and current.

An ideal differentiator using a capacitor.
An ideal differentiator using an inductor.


 

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