Patent ID: 8760148
Filing Date: 2014-06-24
Classification: H04B

Abstract:
1. A Passive Intermodulation (PIM) measurement instrument comprising: a first oscillator providing a signal at frequency F1; a first amplifier having a signal input connected to the first oscillator, a power supply input and a signal output; a first pulse width modulator (PWM) connected to the power supply input of the first amplifier; a first isolator having an input connected to the output of the first amplifier and having an output; a second oscillator providing a signal at frequency F2 that is different that the frequency F1 of the first oscillator; a second amplifier having a signal input connected to the second oscillator, a power supply input and a signal output; a second PWM connected to the power supply input of the second amplifier; a second isolator having an input connected to the output of the second amplifier and having an output; and a signal combiner receiving the output of the first isolator and the second isolator and providing an PIM measurement signal with a combined signal frequency F1 and F2; wherein active portions of a duty cycle of the first PWM are synchronized to active portions of a duty cycle of the second PWM and inactive portions of the duty cycle of the first PWM are synchronized to inactive portions of the duty cycle of the second PWM such that a power supply of the first amplifier is actively connected to the first amplifier at substantially the same time that a power supply of the second amplifier is actively connected to the second amplifier; and wherein the duty cycle of the first PWM and the duty cycle of the second PWM are preset based on target direct current (DC) power consumption of the PIM measurement instrument.