Multi frequency MLA

The newly launched multi frequency lock-in amplifier MLA by Haoliang Optoelectronics provides a new method for measuring linear and nonlinear systems. MLA has a bandwidth of 80MHz, 6 outputs, 4 inputs, and 6 flip flops. All synchronized to a global reference signal, covering a wide range of applications. It can be used as an arbitrary waveform generator, frequency counter, spectrum analyzer, network analyzer, and 32 frequency lock-in amplifierMLA is multi frequency, multi port, and multi-purpose.

Principle - Single Channel ImplementationMulti frequency measurement

The special feature of MLA is that all input signal components can be locked to a reference oscillation, using a special digital algorithm to achieve multiple synchronous locks, so that all locked frequencies operate under the same reference oscillation. This synchronous operation mode ensures that all input signals are integer multiples of the measurement bandwidth by adjusting their frequenciesTo achieve; In other words, all frequencies can be locked onto a reference oscillation of a given bandwidth. This new implementation method is called tuning, and based on this analysis approach, MLA appears particularly powerful in detecting nonlinearity, supporting analysis of up to 32 frequencies, as shown in the figure on the right

Error - Avoiding Spectrum Leakage

When performing FFT transformation on signals, a portion of discrete data is usually selected for processing, which can be referred to as a frame of data. Moreover, FFT is performed under certain assumptions, assuming that the processed signal is a periodic signal. Therefore, before FFT, this frame of data will be periodically extended. But if the selected frame of data is not an integer multiple of the signal period, as shown in the red dot selection in the left figure, there will be discontinuity in the sample points during period extension, which will cause distortion in the spectrum obtained after FFT.

Just like in the left image where there were originally only three frequencies (blue signal), due to spectral leakage, the selected points were periodic points that should have been blue, but were actually red points, resulting in a large number of frequencies that were originally 'non-existent' after FFT transformation. MLA devices use tuning, which adjusts the frequency of all input signals to be an integer multiple of the measurement bandwidth to avoid Fourier leakage, as shown by the black grid on the frequency axis in the left figure

Flexible - Suitable for various experiments

MLA's graphical user interface (GUI) has a built-in Python script panel, allowing you to directly access the application programming interface (API) within the GUI. GUI is easy to use and suitable for various types of measurements. Through a user manual that includes a large number of example programs and complete documentation of APIs, measurement software can achieve a wide range of functions! Including：

Measurement transmission function.

Lock harmonic and modulation products.

Quickly monitor broadband response.

Trigger and double the trigger lock measurement.

Arbitrary bias and precise timing.

Frequency domain multiplexing.

Event counting during the measurement process.

Parameter specifications

◆4 signal inputs (DC -80 MHz)

◆10 MHz reference clock input and output

◆2 signal outputs (DC -80 MHz)

◆4 non metric outputs (DC -100 kHz)

◆Sampling frequency up to 250 MSPS

◆Gbit Ethernet connection for control/data transmission

◆Input/output resolution both up to 16 bits

Unique advantages and applications

◆ 32 frequency lock-in amplifier

◆Python based software with high degree of freedom and easy implementation of a large number of control functions

◆Powerful non-linear signal detection

◆There is no spectrum leakage, ensuring the accuracy of the output signal!

◆It has functions such as waveform generator, spectrum analyzer, network analyzer, frequency counter, etc

◆Customized software/supporting units can be provided based on user needs

◆Widely used for demodulation of excitation signals in multi frequency atomic force microscopy (MF-AFM)

◆Related designs to support quartz crystal microbalance (QCMD)

If you would like to learn more, please download the relevant materials or contact us