Agilent AN150-7 Spectrum Analysis - Signal Enhancement June75 free download

File name AN150-7 Spectrum Analysis - Signal Enhancement June75.pdf

Errata Title & Document Type: Application Note 150-4: Spectrum Analysis Signal Enhancement Manual Part Number: unknown Revision Date: June 1975 HP References in this Manual This manual may contain references to HP or Hewlett-Packard. Please note that Hewlett- Packard's former test and measurement, semiconductor products and chemical analysis businesses are now part of Agilent Technologies. We have made no changes to this manual copy. The HP XXXX referred to in this document is now the Agilent XXXX. For example, model number HP8648A is now model number Agilent 8648A. About this Manual We've added this manual to the Agilent website in an effort to help you support your product. This manual provides the best information we could find. It may be incomplete or contain dated information, and the scan quality may not be ideal. If we find a better copy in the future, we will add it to the Agilent website. Support for Your Product Agilent no longer sells or supports this product. You will find any other available product information on the Agilent Test & Measurement website: www.tm.agilent.com Search for the model number of this product, and the resulting product page will guide you to any available information. Our service centers may be able to perform calibration if no repair parts are needed, but no other support from Agilent is available. " " rj3'HEWLETT ~~ PACKARD " r~ ..' CHAPTER 1 ,"} . . Basic Considerations Definition of Sensitivity Sensitivity, to be useful, needs to relate to how small a signal can be measured on the analyzer. The CRTdeflection is always proportional to the total power which includes the signal and the noise. A signal can be seen when it is equal to the noise power. S+N S=Nor-=2 (1), where N S = power of the signal N = power of the noise In this case, S + N will be twice the noise power or deflected 3 dB above the noise. Available Noise Power The input termination of a network (an amplifier, receiver, or spectrum analyzer) has a certain amount of available noise power which is, in most cases, thermal noise. An impedance Z = R + jX at temperature T generates across its open circuit terminals a voltage resulting from the random motion of free electrons thermally agitated. This "noise voltage", en, can be defined by the equation: