ECE345 Electronics Laboratory 10_2010

ECE345 Electronics Laboratory 10_2010 - Laboratory 10...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Laboratory 10 Synchronous Detection ECE345 Electronics Laboratory Detecting Small Signals Several techniques have been developed for detecting signals in the presence of noise If the signal has a narrow bandwidth, then filters can be used to eliminate interfering signals that have frequencies close to the signal of interest. Digital filtering is an increasingly popular way to recover signals from noise Synchronous detection or lock-in amplifiers also work well if the signals has a known frequency. Synchronous Detection The signal accompanied by noise is multiplied by a sine wave or square wave (called the Reference Signal) of the known frequency, and the result is averaged: If two sine waves are multiplied, then the result is two cosine waves whose frequencies are the sum and difference of the two initial frequencies The average of a sine or cosine wave is zero over time. If u=v, then the average is or non-zero! The reference signal can be a square wave since it is a sum of sine or cosine waves....
View Full Document

This note was uploaded on 02/01/2011 for the course ECE 330 taught by Professor Foster during the Spring '10 term at Johns Hopkins.

Page1 / 15

ECE345 Electronics Laboratory 10_2010 - Laboratory 10...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online