The NISM software for the E5061B converts impedance into phase margin (2.1 degrees) in order to assess stability.
Non Invasive Stability Measurement, or NISM, is a powerful technique for measuring the stability of control loops. The NISM software, embedded in commonly used VNAs, converts output impedance to phase margin. This is extremely useful considering that many of today's power ICs do not have their control loops exposed, and in fact, in those cases, NISM is the only way to make an accurate stability measurement.In this example, the output impedance of a voltage reference is measured. The VNA Keysight E5061B VNA, is used to measure the impedance at the output of the reference. The impedance is then converted to phase margin using a simple cursor measurement as shown below.
Key Features:
- Easy-to-Use - Convert Output Impedance to Phase Margin
- Add stability testing to the Keysight E5061B vector network analyzer
- Filters, Opamp, Regulators (Linear and Switching), POLs, Amplifiers, References
- Works with 1, 2 and 3 Port measurements (high and low frequency ports)
- Print and Save Results
- Works even when you can't break the control loop
- Works In-Circuit
- Within 1 degree of Bode Plot Results (from 1 to 65 degrees).
- Measure what Bode Plots can't