Products » Lock-In Amplifiers

Lock-In Amplifiers

Powered by 32-bit ARM technology, these unique mixed-signal instruments have native full-speed USB 2.0 compliant interfaces, and also can operate in standalone mode. They deliver high performance in a compact package, and are specifically engineered to solve problems encountered in high-channel-count OEM applications.

All our demodulators are manufactured in Colorado using a rigorous seven-step quality control process, and are backed by our 12-month warranty. All are 100% RoHS compliant.

µLIA-320: Standalone Lock-in Amplifier with USB interface

This is a dual-phase USB 2.0 compliant demodulator with streaming analog-to-digital (x, y) samples of the demodulated signal, for use in general applications where the measured signals are weak and noisy. An economical alternative to high-end lock-in amplifiers, specifically designed for high-channel-count OEM applications. The µLIA-320 is also well-suited for undergraduate & graduate physical-science lab experiments.

[New!] Our Rev. E µLIA-320 USB lock-in amplifiers are now available! Featuring more dynamic range, improved accuracy, wider operating-temperature range, and analog sinusoidal Reference Output capability. Contact us for further details.

[uLIA-320 USB lock-in amplifier front & back]
µLIA-320 Specifications
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See our µLIA-320 FAQ section below for frequently-asked questions about this product! All user manuals & downloads are accessible from the Support page of our web site. If you would like to review this material, please contact us and we will provide log-in information.


['uLIA-320 Panel' application for USB lock-in amplifier]

µLIA-321: Application-specific Lock-in Amplifier

A customized version of the µLIA-320, intended for OEM applications. Please contact us with your exact application needs.


µLIA-320 USB Lock-In Frequently Asked Questions

1. What types of reference signals does the µLIA-320 accept?
The reference input accepts logic-level TTL-compatible signals of arbitrary duty cycle. The reference input is opto-isolated from the rest of the instrument.

2.What is the lowest input reference frequency the µLIA–320 will accept?
The µLIA-320 accepts reference frequencies as low as 800 Hz. Many potential customers are interested in the ~1 kHz to 10 kHz frequency range, which the µLIA-320 handles well.

3. What is the minimum time constant available?
The minimum (“fastest”) time constant is 1 ms, and is determined by the bandwidth of the demodulator low-pass anti-aliasing filters. Selecting “0 ms” in uLIA-320 Panel or the uLIA_dd toolkit will return (x, y) samples with this inherent bandwidth only and no additional digital low-pass filtering.

4. What is the phase resolution of the µLIA–320?
The phase resolution or adjustability of the X and Y channels relative to the reference channel is 0.1 degrees. This value is determined by the bit-width of the Direct Digital Synthesis (DDS) phase-tuning registers. The µLIA-320 utilizes DDS’s with 12-bit phase-tuning registers, hence the underlying settability of the reference channel phase is one part in 4096.

5. Is the µLIA-320 an analog lock-in or a DSP lock-in?
The µLIA-320 is a modern digitally-controlled mixed-signal approach to an analog sine-wave multiplier lock-in amplifier. This recovery approach is similar to the Stanford Research SR510 & SR530 analog lock-ins. The front-end gain blocks, analog multipliers, and back-end demodulator low-pass filters are pure analog, and are designed to handle the full instrument bandwidth (400 kHz). These analog blocks do the 'heavy lifting' of the instrument, allowing the recovered quasi-DC baseband to be sampled at 1 ksample-pair/sec, digitally low-pass filtered, and (x, y) samples streamed over USB to the host PC.

6. Is there software provided that allows me to integrate the µLIA–320 into my existing application?
Yes. The uLIA_dd device-driver toolkit provides an API for the host/µLIA-320 message protocol for users that desire to tie the lock-in functionality into their own software. Source code & technical support for the uLIA_dd toolkit are included with the µLIA-320.

7. Does the µLIA-320 measure AC current?
Not directly. The µLIA-320 accepts bipolar voltage inputs in the ±10V range on the front-panel Signal Input BNC. This input is AC-coupled to a FET input amplifier. Current inputs must first be converted to the voltage domain by an appropriate transimpedance amplifier for the sensor.

8. What is the highest frequency the µLIA–320 can recover?
The µLIA-320 can recover signals up to 400 kHz.

9. Can I use the µLIA–320 in standalone mode, without a PC?
Yes. The front-panel Monitor Output BNC outputs one of four internal analog signals. The µLIA-320 must first be configured by the host while attached to USB, and the X or Y DC output selected by software as the Monitor Output. When the µLIA-320 is detached from USB, the lock-in will hold its last-set configuration, and the selected X or Y signal will continue to appear on Monitor Output.

10. Does the µLIA–320 come with a display screen?
The µLIA-320 has a ‘virtual’ display screen through the uLIA-320 Panel program, on your desktop PC or laptop. This virtual front-panel is far more versatile and economical than any dedicated display screen we could provide.

11. Do you have any drivers/libraries that would allow me to control the µLIA-320 and collect data using a Raspberry Pi (Linux-like) or some other UNIX based operating system?
Not directly. The µLIA-320 ships with the uLIA_dd device-driver toolkit, which handles the details of the host/lock-in message protocol. This toolkit calls into the WinUSB & Registry interface module uLIAUsb.dll, which is specific to Microsoft Windows. Source code (standard C) is provided for the uLIA_dd toolkit, but not for the underlying .DLL. For a different operating environment than Windows (e.g. Raspberry Pi), there are a small number of USB API calls that would have to be implemented in order to port the uLIA_dd toolkit. Contact us for further details.

12. Is the µLIA–320 a USB bus-powered device?
No. The µLIA-320 has its own separate international power supply and thus draws negligble power from the USB bus.


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