Posts tagged Sweeper

Connect MFLI with External Signal Generator

on 26.07.2019 at 16:18 by Marco Brunner on Blog of Marco Brunner
This blog describes how to use an MFLI lock-in amplifier with an external reference frequency. The reference frequency comes from a signal generator Model 6221 from Keithley which is used to apply higher voltage pulses or sinusoidal signals on the […]

Frequency-Domain Response of Lock-in Filters

on 19.03.2019 at 18:10 by Mehdi on Blog of Mehdi Alem
Introduction  The response of a lock-in amplifier is characterized by the parameters of its low-pass filter (LPF), i.e. time constant and filter order. The temporal response of the LPF demonstrates the latency of measurement while its spectral response shows the […]

Kramers–Kronig Test Applied to Impedance Measurements of Electrical Circuits

on 25.09.2017 at 06:57 by Mehdi on Blog of Mehdi Alem
Introduction  In this post, the Kramers-Kronig relations are used to verify the results of an impedance measurement experiment performed by the Zurich Instruments MFIA Impedance Analyzer or MFLI Lock-in Amplifier equipped with the MF-IA option. The Kramers-Kronig relations state that the real […]

Noise Analysis of Signal Components

on 29.03.2017 at 13:57 by Mehdi on Blog of Mehdi Alem
Introduction  In this post, the relation between the noise of signal amplitude and phase on one hand and the noise of in-phase and quadrature components of the signal on the other hand is investigated. We try to respond to the wrong […]

The Nyquist Diagram for Electrical Circuits

on 11.01.2017 at 07:10 by Mehdi on Blog of Mehdi Alem
Introduction The Nyquist diagram of a transfer function is a parametric plot of its imaginary part versus real part as the frequency sweeps in a certain range [1]. When dealing with electric circuits, the transfer function is the immittance [2] of the […]

Frequency Response Measurement with Chirps and Leakage-Free FFT

on 28.10.2016 at 16:08 by brunok on Blog of Bruno Küng
Introduction This post explains how to measure the frequency response of a component or system with high spectral resolution in a minimum amount of time. Rather than sweeping the frequency and recording each spectral point individually, the approach presented here is […]

Better Amplitude Accuracy with MFLI Analog Adder

on 07.03.2016 at 17:47 by brunok on Blog of Bruno Küng
Many lock-in applications use a drive signal consisting of a small AC excitation voltage and larger DC offset voltage, for example differential conductance (dI/dV) measurements. Users of the MFLI Lock-in amplifier have the choice between two methods to generate such a signal: […]

Eddy Current Testing with MFLI Lock-In Amplifier

on 05.08.2015 at 12:07 by Marco Brunner on Blog of Marco Brunner
This blog describes a method to detect material defects. Eddy current measurements are used for non-destructive material testing (NDT). An alternating magnetic field is penetrating a sample. The material defect is detected by a phase shift. In the first part […]

Optimize Your Frequency Sweep for Static Impedance Measurement

on 28.02.2013 at 08:20 by James Wei on Blog of James Wei
Very often people want to measure very large static impedance (e.g. small capacitance, large resistance) over a wide frequency range. In the very low frequency region, one may notice that measured curve is not smooth but rather “jiggly”, just like […]

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