Accession Number : ADA626973


Title :   Characterization of Passive Spectral Regrowth in Radio Frequency Systems


Descriptive Note : Doctoral thesis


Corporate Author : NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF ELECTRICAL AND COMPUTER ENGINEERING


Personal Author(s) : Wetherington, Joshua M


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a626973.pdf


Report Date : Jan 2013


Pagination or Media Count : 166


Abstract : Passive spectral regrowth is the generation of nonlinear frequency content as a signal passes through a passive system. The nonlinearity may be a result of the intermodulation between individual signal components or signal components coupling to and mixing with energy in non-electromagnetic domains. Passive spectral regrowth is much weaker than regrowth in active devices due to the lack of gain, however characterization of the new spectral content is growing in importance as the sensitivity of radio-frequency (RF) receivers improves. Passive components at the end of an RF chain, including the antenna, can produce distortion that is difficult to remove using conventional filtering techniques. Alternatively, understanding of the nonlinear mixing may be exploited in RF sensing for unique characterization of remote or difficult-to-reach objects. To better understand passive spectral regrowth, an investigation is undertaken to experimentally and analytically characterize the nonlinear effects of spectral-regrowth-generating phenomena on an RF signal. Detection of low-level passive spectral regrowth close in frequency to a high-power stimulus signal requires extreme dynamic range measurement capability not available on commercial, o -the-shelf equipment. To enable these measurements, a high-dynamic-range nonlinear measurement system is built using analog cancellation. Automated analog cancellation with careful attention to signal path calibration and non-iterative phase calculation is key to achieving up to 140 dB of dynamic range in two-tone characterization with tones separated by at least 1 kHz.


Descriptors :   *NOISE(ELECTRICAL AND ELECTROMAGNETIC) , *PASSIVE SYSTEMS , *RADIOFREQUENCY , AMPLITUDE MODULATION , ANTENNAS , BANDWIDTH , DIGITAL TO ANALOG CONVERTERS , DISTORTION , DOPPLER SYSTEMS , DYNAMIC RANGE , ELECTROMAGNETIC INTERFERENCE , ELECTROMAGNETIC SCATTERING , EXPERIMENTAL DESIGN , FERROMAGNETISM , HIGH DYNAMIC RANGE , INTERMODULATION , NONLINEAR SYSTEMS , PHASE MODULATION , RADAR CROSS SECTIONS , RADIO RECEIVERS , SIGNAL GENERATORS , THERMAL RESISTANCE , THESES , VIBRATION


Subject Categories : Active & Passive Radar Detection & Equipment
      Electricity and Magnetism
      Radiofrequency Wave Propagation
      Radio Communications


Distribution Statement : APPROVED FOR PUBLIC RELEASE