1. Measure loop gain and phase shift versus frequency (called a Bode plot or transfer function) of any feedback loop, including numeric display of phase and gain margins.
2. Measure the transfer function of any piece of a loop.
3. Measure input / output impedance of any system.
4. Measure impedance versus frequency of components, including converting the data into actual circuit values. For example, you can read the capacitance, internal resistance, and internal inductance of any capacitor directly in component values.
5. Measure the transfer function of any passive or active filter.
6. Measure the resonant characteristics of crystals.
7. Measure the DC resistance, open circuit inductance, self-resonant frequency, and winding capacitance of any transformer or inductor.
8. Measure the leakage inductance of any transformer (and DC winding resistance, also).
9. Measure the impedance of diodes at their actual operating point. This is especially helpful when modeling optocouplers.
10. Measure current transfer ratio (CTR) of optocouplers, including the AC effects and bandwidth.
11. Measure the closed-loop gain (gain from reference to output) of circuits that are difficult to measure open-loop such as the current loop in current mode converters.
12. Measure exotic loops, like phase-locked loops.
13. Measure conducted emissions and power line harmonics.
14. Measure conducted susceptiibility (ability to reject input noise at a power supply output).
15. Measure the DC gain, open loop bandwidth, phase margin and output impedance of any amplifier, including those internal to integrated circuits.
16. Measure unusual or sensitive impedances such as the effective impedance of integrated circuit pins. For example, pin 1 (the comp pin) of a UC3844 (which turns out to be 11K resistive) or the control pin of the Power Integrations TOPS family of 3-terminal switchers (which turns out to be 15 ohms resistive).
17. Model the frequency response of any circuit.
18. Overlay model and test results to quickly and easily determine the accuracy of any model.
19. Mathematically combine model results and measurements. For example, measure the part that is hard to model (the power circuitry), then model the part that is easy to model (the error amplifier), and then play with the model until you achieve the overall results you want.
20. Document plots so that tomorrow or next year you will know what the plot and test conditions were. This is done easily and semi-automatically with Venable systems.
21. Save setups and test data on disk, so you can repeat the same test with the same conditions, even years from now. This is especially useful when determining if a vendor has changed anything in a product over a long period of time.
22. Transfer data automatically into Excel and effortlessly make Bode or impedance plots.
23. Transfer Excel plots to Word for easy, professional-looking documentation for customers or design review packages.
24. Automatically compensate feedback loops for the exact bandwidth and phase margin you want on the first try.
25. Do any kind of math requirement on transfer functions, such as add, subtract, multiply, divide, or the same functions with one transfer function and a number or time delay. Functions can also subtract time delays from test data.

© Copyright Venable Corporation 2002