Lock-in Amplifiers

The Nyquist Diagram for Electrical Circuits

11.01.2017

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. When dealing with electric circuits, the transfer function is the immittance of the circuit, i.e., it can be either the impedance or the admittance of the circuit...

Frequency Response Measurement with Chirps and Leakage-Free FFT

28.10.2016

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 based on a fast and continuous change of the frequency...

Better Amplitude Accuracy with the MFLI Analog Adder

07.03.2016

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: using the analog adder ("Add"), or using digital...

Using Digital Lines as Trigger Sources

03.02.2016

Starting from the LabOne 15.11 release, accessible from our Download Center , all HF2LI users with the enabled HF2LI-WEB option can now benefit from the latest software developments that were previously reserved for the UHFLI. One tool that is now totally new for this instrument is the Software (SW) Trigger...

LabOne Software Trigger as a Tool for Multichannel Mapping Applications

25.11.2015

In earlier blog posts, I presented several methods to synchronize data acquisition with third party instruments, either via the DIO input as a h ardware trigger (TTL pulse), some gated triggering scheme for pass/fail analysis or to capture only transient phenomena in a longer data stream ( ring-down method example)...

Eddy Current Testing with the MFLI Lock-in Amplifier

05.08.2015

This blog post 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. Experimental Setup

Optimizing PLL Performance with PID Advisor and Auto Tune

27.07.2015

LabOne provides two tools that save time and improve performance for anybody working with the UHF-PID option: the PID Advisor and the Auto Tune feature. They enable automation of the feedback parameter tuning required to achieve the best PID (proportional-integral-derivative) controller performance. In this blog post, we'll show you an example that demonstrates the power of both of these tools...

Achieving High Data Transfer Rates with the UHFLI

07.07.2015

The UHFLI Lock-in Amplifier features the smallest time constant on the market, making it an excellent instrument for fast measurements like in imaging applications. The UHFLI can provide demodulated data at a bandwidth of up to 5.2 MHz and sampled at up to 14 MSa/s...

Measuring the I-V Characteristic of PN Junction Devices with the HF2LI

13.05.2015

Co-author and main contributor: Dr. Antonio Braga Introduction The p-n junction is the fundamental building block of semiconductor material electronics device such as transistors, diodes, sensors, laser, light emitting diodes, as well as solar cells. If one wants to know the fundamental functional properties of these devices, it is crucial...

Demodulating Down to DC with the HF2LI

18.11.2014

Many of our customers use the possibility to measure DC voltage and current, together with an ac signal by setting the demodulation frequency ω=0. The measured value is seemingly incorrect as you need to divide the obtained rms value with the factor of √2 to get the actual signal amplitude...