A Simple Microcontroller Based Digital Lock-in Amplifier for the Detection of Low Level Optical Signals
نویسندگان
چکیده
Traditionally digital lock-in amplifiers sample the input signal at a rate much higher than the lock-in reference frequency and perform the lock-in algorithm with high-speed processors. We present a small and simple digital lock-in amplifier that uses a 20 bit current integrating analogue-to-digital converter interfaced to a microcontroller. The sample rate is set to twice the reference frequency placing the sampled lock-in signal at the Niquest frequency allowing the lock-in procedure to be performed with one simple algorithm. This algorithm consists of a spectral inversion technique integrated into a highly optimised low-pass filter. We demonstrate a system with a dynamic range of 103dB recovering signals up to 85dB below the interference.
منابع مشابه
Designing an Integrated All-Optical Analog to Digital Converter
We present the procedure for designing a high speed and low power all-optical analog to digital converter (AO-ADC), by integrating InGaAsP semiconductor optical amplifier (SOA) with InP based photonic crystal (PhC) drop filters. The self-phase modulation in the SOA can shift the frequency of the Gaussian input pulse. The two output PhC based drop filters are designed to appropriately code the f...
متن کاملUnified Pulsed Laser Range Finder and Velocimeter using Ultra-Fast Time-To-Digital Converter
In this paper, we present a high accuracy laser range finder and velocimeter using ultra-fast time-to-digital converter (TDC). The system operation is based on the measuring the round-trip time of a narrow laser pulse. A low-dark current high-speed PIN photodiode is used to detect the triggered laser beam and to produce start signal. The pulsed laser diode generates 45W optical power at 30ns du...
متن کاملLow Level Optical Detection using Lock-in Amplifier Techniques
This note describes a number of techniques that can be used to detect low level optical signals. It starts by considering the problems inherent in the use of DC techniques and how these may be reduced by using AC methods instead. It then discusses a range of different experimental approaches using lock-in amplifiers, pointing out the advantages as well as any disadvantages of each method. Final...
متن کاملA High Performance LIA-Based Interface for Battery Powered Sensing Devices
This paper proposes a battery-compatible electronic interface based on a general purpose lock-in amplifier (LIA) capable of recovering input signals up to the MHz range. The core is a novel ASIC fabricated in 1.8 V 0.18 µm CMOS technology, which contains a dual-phase analog lock-in amplifier consisting of carefully designed building blocks to allow configurability over a wide frequency range wh...
متن کاملA Proposal for a New Method of Modeling of the Quantum Dot Semiconductor Optical Amplifiers
With the advancement of nanoscale semiconductor technology,semiconductor optical amplifiers are used to amplify and process all-optical signals. Inthis paper, with the aim of calculating the gain of quantum dot semiconductor opticalamplifier (QD-SOA), two groups of rate equations and the optical signal propagatingequation are used in the active layer of the device. For t...
متن کامل