Fundamentals of Electrical

by Kurt Stern Jan 2004

1 WhiteWhite NoiseNoise

• In 1928 Johnson and Nyquist ID the Problem • Nyquists Theorem P = KTB P = Noise Band power in Watts T = Temp Degree (T) K = Boltzmans Constant 1.38X10-23 B = Bandwidth (Hertz)

2 Excess Noise Ratio in dB

ENR=10Log((T/290)-1)

T in Kelvin is the temperature of a resistor

3 NoiseNoise GeneratingGenerating DevicesDevices

4 NoiseNoise EquivalencyEquivalency ReferenceReference ChartChart

5 ApplicationsApplications ofof NoiseNoise TechnologyTechnology

• Measure • Gain and Bandwidth Parameters • Susceptibility to External Interference • Jamming • System Self Test

6 NoiseNoise MeasurementsMeasurements

• The Radiometer • Noise Standards • Calibration of Noise Standards • Errors in Noise Measurements

7 BasicBasic SwitchingSwitching RadiometerRadiometer

8 Simplified Automate Radiometer

9 NISTNIST AutomatedAutomated RadiometerRadiometer

10 NBSNBS SwitchingSwitching RadiometerRadiometer

11 CommercialCommercial SwitchingSwitching RadiometerRadiometer

12 CommercialCommercial SwitchingSwitching RadiometerRadiometer

(Specifications for the PRD 915-B Attenuation Calibrator)

13 Noise Figure Measurements

• Y Factor • Twice Power Measurements • Automatic Measurements • Noise Figure to Temperature

14 Y Factor

15 Twice Power NF Measurement

16 17 Noise Figure vs. Noise Temperature Conversion Chart

18 ENR Measurement VSWR Error

19 20 Noise Source UUT VSWR Error

21 AutomaticAutomatic NoiseNoise FigureFigure MeterMeter

22 Noise Figure Equivalence Chart

23 ApplicationsApplications byby IndustryIndustry

• Military • Electronics Manufacturing • Communications

24 Noise Standards

• Characteristics - Flat Power Spectrum - High Degree of Stability • 3 Classes - Noise Diodes - Gas-Discharge Tubes - Thermal Noise Sources

25 Generation of Noise

26 Thermal Noise Calculation

27 Avalanche Noise Region

28 Vacuum Diode Noise Source

29 High Temperature Noise Standard

30 Low Temperature Noise Standard

31 Low Temperature Thermal Conductivity

32 Error Flow Diagram

33 DUT Noise Temperature Errors

34 USA-England Intercomparison

35 USA-Sweden Intercomparison

36 NoiseNoise AmplificationAmplification

• Bandwidth Power • Crest Factor

37 CrestCrest FactorFactor (CF)(CF)

38 Gaussian NoiseNoise DistributionDistribution

39 Bandwidth & Power

• Noise Power = Unit noise power X bandwidth • Consequently for some designs wider bandwidths may require a higher compression point amplifier

40 Communications Systems Testing

• White Noise Testing • Bit Error Rate vs. Noise

41 WhiteWhite NoiseNoise TestingTesting

42 WhiteWhite NoiseNoise TestTest EquipmentEquipment

• Noise Generator

• Noise Receiver

43 44 ATMATM NoiseNoise SourcesSources (Z(Z Model)Model)

45 ATMATM NoiseNoise SourceSource (Y(Y Model)Model)

46 47 48 49 Thank You

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