Introduction: Understanding the Composition of an Input Signal |
In precision physics and electrical engineering, raw input signals are rarely clean. When setting up an experiment, the signal under test (SUT) typically carries two distinct types of information simultaneously:
The Target AC Signal: The useful alternating current signal that holds the actual physical data from your experiment.
Broadband Noise: Unwanted background interference, such as thermal noise, flicker (1/f) noise, and environmental pickup, which often overwhelms the target signal.
The Core Function: What Information Can a Lock-in Amplifier Extract? |
Because the raw input is deeply buried in noise, standard measurement tools like digital voltmeters often fail. A lock-in amplifier is specifically designed to bypass the noise and extract only the essential characteristics of the synchronous AC signal.
Specifically, a lock-in amplifier can only measure two core pieces of information:
The Amplitude Value: The exact magnitude (peak or RMS voltage) of the specific AC component matching the reference frequency.
The Phase Value: The precise phase angle relationship between the input signal and the reference clock.
By isolating these two variables, the instrument effectively ignores the surrounding noise, allowing researchers to calculate the true properties of the underlying physical phenomenon.
Related products: |
Lock-In Amplifiers: Principle, Applications & Products | Saluki Technology
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