ABSTRACT
Noise, simply put, is any unwanted signal that interferes with the detection of the desired signal. Increasing the value of number of measurements would increase the signal-to-noise ratio, as random value of noise will be nullified. The fluctuation in statistics is a shot noise. Shot noise is also encountered when electrons or other charged particles cross ajunction and it essentially arises due to the particulate nature of the electrons. Improving the signal-to-noise ratio is crucial when high sensitivity and accuracy is required. Hardware noise reduction processes involve addition of shields, filters, synchronous detectors prior to the amplification stage. Filters are useful for rejecting noise in a particular frequency regime. The lock-in-amplifier is based on the phase sensitive detection, which can be used to improve the signal-to-noise ratio considerably even if the signal is buried completely in the noise.
