Noise and InterferenceNoise is a random variation of the value of themeasured signal as a consequence of the variation ofthe extraneous variables. Noise increases data scatter.Interference imposes undesirable deterministictrends on the measured value. Any uncontrolledinfluence that causes the signal or test outcome tobehave in a manner different from its true behaviouris interference
Noise and Interference Noise is a random variation of the value of the measured signal as a consequence of the variation of the extraneous variables. Noise increases data scatter. Interference imposes undesirable deterministic trends on the measured value. Any uncontrolled influence that causes the signal or test outcome to behave in a manner different from its true behaviour is interference
Noise and Interferenceinterferenceimposes atrendSignal:y(t)=2+sin (2t)onto the signal5Signal+interference4(esSignal +noisenoise adds to2the scatter of the signal.00.52.00.01.01.5Time (s)
Noise and Interference noise adds to the scatter of the signal. interference imposes a trend onto the signal
Random.Tests: In general, consider the situation in which the dependent variable, yis a function of several independent variables, xa, xb, :However, the measurement of y can also be influenced by severalextraneous variables, zj, where j = 1, 2, : : : , such that y = f(xa, xb; : . ; zi) To find the dependence of y on the independent variables, they arevaried in a controlled manner. Although the influence of the zjvariables on these tests cannot be eliminated, the possibility of theirintroducing a false trend on y can be minimized by a proper teststrategy
Random Tests • In general, consider the situation in which the dependent variable, y, is a function of several independent variables, xa, xb, . . . . • However, the measurement of y can also be influenced by several extraneous variables, zj, where j = 1, 2, . . . , such that y = f (xa; xb; . . . ; zj) • To find the dependence of y on the independent variables, they are varied in a controlled manner. Although the influence of the zj variables on these tests cannot be eliminated, the possibility of their introducing a false trend on y can be minimized by a proper test strategy
RandomizationWe define a random test by a measurement matrix that sets arandom order to the change in the value of the independentvariable applied. The effect of the random order on the results ofthe test is termed randomization. Trends normally introduced by the coupling of a relatively slowand uncontrolled variation in the extraneous variables with asequential application in values of the independent variableapplied will be broken up
Randomization • We define a random test by a measurement matrix that sets a random order to the change in the value of the independent variable applied. The effect of the random order on the results of the test is termed randomization. • Trends normally introduced by the coupling of a relatively slow and uncontrolled variation in the extraneous variables with a sequential application in values of the independent variable applied will be broken up
CaseStudy#1ExtraneousvariablesOpentoPoweratmospheresourcePressurePTtransducerVoltmeterPistonCylinderKNOwNPressurecalibrationsystemFIND Independent, dependent, and extraneous variables
Case Study #1 KNOWN Pressure calibration system FIND Independent, dependent, and extraneous variables