Passive intermodulation(PIM)in communication systems is an unwanted interference caused by weak nonlinear currentvoltage characteristics of radio frequency(RF)passive components.Characterization of PIM is important fo...Passive intermodulation(PIM)in communication systems is an unwanted interference caused by weak nonlinear currentvoltage characteristics of radio frequency(RF)passive components.Characterization of PIM is important for both the study of PIM mechanisms and the location/suppression of PIM sources.PIM probes,made of open-ended coaxial transmission lines,have almost the same coupling strength to carriers and PIM products,and are usually used for near-field PIM characterization.Namely,it doesn’t have any filtering capability.Therefore,it cannot stop the carrier power from entering into PIM tester’s receiver,which may trigger active intermodulation of the receiver and degrade the PIM tester’s performance.To overcome this drawback,a passive filtering coaxial probe is proposed here.Compared with existing passive coaxial PIM probes,it has stronger coupling strength for PIM products than for carriers.Thus,the probe itself can block part of the carrier power entering into the PIM tester’s receiver.This advantage helps improve PIM tester’s overall performance.Both theoretical analysis and experiments are conducted for demonstration.The proposed probe brings more possibility to PIM characterization.展开更多
A novel method is developed by utilizing the fractional frequency based multirange rulers to precisely position the passive inter-modulation(PIM)sources within radio frequency(RF)cables.The proposed method employs a s...A novel method is developed by utilizing the fractional frequency based multirange rulers to precisely position the passive inter-modulation(PIM)sources within radio frequency(RF)cables.The proposed method employs a set of fractional frequencies to create multiple measuring rulers with different metric ranges to determine the values of the tens,ones,tenths,and hundredths digits of the distance.Among these rulers,the one with the lowest frequency determines the maximum metric range,while the one with the highest frequency decides the highest achievable accuracy of the position system.For all rulers,the metric accuracy is uniquely determined by the phase accuracy of the detected PIM signals.With the all-phase Fourier transform method,the phases of the PIM signals at all fractional frequencies maintain almost the same accuracy,approximately 1°(about 1/360 wavelength in the positioning accuracy)at the signal-to-noise ratio(SNR)of 10 d B.Numerical simulations verify the effectiveness of the proposed method,improving the positioning accuracy of the cable PIM up to a millimeter level with the highest fractional frequency operating at 200 MHz.展开更多
文摘Passive intermodulation(PIM)in communication systems is an unwanted interference caused by weak nonlinear currentvoltage characteristics of radio frequency(RF)passive components.Characterization of PIM is important for both the study of PIM mechanisms and the location/suppression of PIM sources.PIM probes,made of open-ended coaxial transmission lines,have almost the same coupling strength to carriers and PIM products,and are usually used for near-field PIM characterization.Namely,it doesn’t have any filtering capability.Therefore,it cannot stop the carrier power from entering into PIM tester’s receiver,which may trigger active intermodulation of the receiver and degrade the PIM tester’s performance.To overcome this drawback,a passive filtering coaxial probe is proposed here.Compared with existing passive coaxial PIM probes,it has stronger coupling strength for PIM products than for carriers.Thus,the probe itself can block part of the carrier power entering into the PIM tester’s receiver.This advantage helps improve PIM tester’s overall performance.Both theoretical analysis and experiments are conducted for demonstration.The proposed probe brings more possibility to PIM characterization.
文摘A novel method is developed by utilizing the fractional frequency based multirange rulers to precisely position the passive inter-modulation(PIM)sources within radio frequency(RF)cables.The proposed method employs a set of fractional frequencies to create multiple measuring rulers with different metric ranges to determine the values of the tens,ones,tenths,and hundredths digits of the distance.Among these rulers,the one with the lowest frequency determines the maximum metric range,while the one with the highest frequency decides the highest achievable accuracy of the position system.For all rulers,the metric accuracy is uniquely determined by the phase accuracy of the detected PIM signals.With the all-phase Fourier transform method,the phases of the PIM signals at all fractional frequencies maintain almost the same accuracy,approximately 1°(about 1/360 wavelength in the positioning accuracy)at the signal-to-noise ratio(SNR)of 10 d B.Numerical simulations verify the effectiveness of the proposed method,improving the positioning accuracy of the cable PIM up to a millimeter level with the highest fractional frequency operating at 200 MHz.
