Principles of lock-in detection

  Enquire / contact me

Description of lock-in detection both in the time and in the frequency domain

Industrial Equipment & Supplies

Principles of lock-in detection
Principles of lock-in detection

Lock-in amplifiers were invented in the 1930’s and commercialized in the mid 20th century as electrical instruments capable of extracting signal amplitudes and phases in extremely noisy environments. They employ a homodyne detection scheme and
low-pass filtering to measure a signal’s amplitude and phase relative to a periodic reference.

A lock-in measurement extracts signals in a defined frequency band around the reference frequency, efficiently rejecting all other frequency components. The best instruments on the market today have a dynamic reserve of 120 dB , which means they are capable of accurately measuring a signal in the presence of noise up to a million times higher in amplitude than the signal of interest. This document provides a quick introduction to the principles of lock-in amplification and explains the most important measurement settings. The lock-in detection technique is described both in the time and in the frequency domain. Moreover, details are laid out on how signal modulation can be exploited in order to improve on signal-to-noise ratio (SNR) while keeping acquisition time low. Finally, recent innovations are discussed and the state of the art is described.

Posted on February 13, 2017 - (1449 views)
Zurich Instruments Ltd
Technoparkstrasse 1
8005 - Switzerland
+41-44-515 0410
+41-44-515 0419-
View full company profile
Location
Related articles
Hannay Works Here
All Springs are not Equal
The Reel That Works as Hard as you
Air Filtering Solutions
Rely on Reelcraft
We run Circles Around the Competition
RFID Safety Switch with Solenoid
System Based High-precision Linkages
Hannay Works Here
Heavy Duty, Premium Duty and Value Hose Reels
Blowdown Evaporators
Versatile Evaporator
Thermally Conductive Epoxy
The Reels That Work As Hard As You
Premium Duty Hose Reels
Low Maintenance e-chain® System
Spongeability
Structural Stability
Extreme Operating Conditions
High Speed Hand Dryer