Connecting the MFLI to an External Signal Generator

July 26, 2019 by Marco Brunner

This blog post describes how to use the 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 sample. In some situations the MFLI can be used as simple pulse generator, as described in this blog post.

In this example the external reference frequency is provided by a signal generator Model 6221 from Keithley. The pin 3 is used as marker and the pin 7 or pin 8 can be used as ground from the 8-pin micro DIN port. A trigger cable like model 8503 DIN to BNC could be used.

Signal-generator.png

Settings of model 6221 AC and DC current source

Picture1.png
  1. Make sure Phase marker output is enabled. (OFF by default)
  2. The default pin is Trigger line.
  3. Modifications are not recommended.

Settings of MFLI Lock-in Amplifier

settings.png

The following screenshot shows that the MFLI is able to use the short pulse from “Phase Marker” of the 6221 which lasts for only 1us as external reference.

pulse-length-1-microsecond.png

Acknowledgments: I would like to thank Yu Wei and Adrian Drzazga for providing support on this topic.

Update: For the HF2LI, the reference signal input should be Signal Input 2 (on front panel), with some restriction DIO (on back panel) can be used.

References

  1. https://www.tek.com/product-series/ultra-sensitive-current-sources-series-6200-manual-0
  2. Model 6220 DC Current Source Model 6221 AC and DC Current Source Reference Manual 622X-901-01 Rev. B / June 2005, Page 213，P249
  3. Model 8503 DIN to BNC Trigger Cable: https://www.tek.com/manual/model-8503-din-bnc-trigger-cable-manual

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