How to Set Two Oscillation Frequencies for the MFIA?

February 9, 2022 by Panhui Huang

Sometimes we want to measure impedance at two different frequencies simultaneously. The second frequency can be either higher-order harmonics or completely independent from the first one. Thanks to the MF-MD Multi-Demodulator option, we can conveniently set this up. In this short blog post, we will walk you through.

The IA interface with MF-MD option installed, you will find two labels named ‘1’ and ‘2’ which corresponds to two IA modules.

Figure 1. The IA interface with MF-MD option installed, you will find two labels named ‘1’ and ‘2’ which corresponds to two IA modules.

To configure the specified oscillators, we need to turn on the Advanced mode (Red frame) and remember to keep it always on during the configuration and measurement. We can look at the Ref freq (Orange frame) and choose the index of the oscillator in the first IA module. By default, it shows '1', the first oscillator, and we do not have to change it. The oscillation frequency can be modified in the green frame. Here we set it to 100 kHz as in the screenshot.

Now let’s turn to the second IA module.

The second IA interface

Figure 2. The second IA interface

In order to use the second oscillator, we should change the oscillator in the orange frame to ‘2’. In doing so, when setting the test frequency to 10 kHz later, we can see the result in Figure 3. Now we have successfully set a second impedance module running at a frequency different from the first one at 100 kHz.

The result in the numeric palette showing the imaginary and real part of the impedance at 100 kHz and 10 kHz.

Figure 3. The result in the numeric palette showing the imaginary and real part of the impedance at 100 kHz and 10 kHz.

As a side note, if we simply want to measure the impedance at the second harmonic of the first oscillation frequency, we can keep the same oscillator index. Changing 'Harm' into 2 is sufficient.