A modular PIM analyzer includes: a first signal amplification module provided with a first signal generator for generating a first frequency signal under control of a first MCU, and a first power amplifier for generating a first amplified frequency signal through the amplification of the first frequency signal under control of a first ALC circuit; a second signal amplification module provided with a second signal generator for generating a second frequency signal under control of a second MCU, and a second power amplifier for generating a second amplified frequency signal through the amplification of the second frequency signal under control of a second ALC circuit; and a triplexer module for extracting a test frequency signal using the first amplified frequency signal and the second amplified frequency signal, transmitting the test frequency signal to a device under test, and receiving a PIM signal being reflected from the device under test

A modular PIM analyzer includes: a first signal amplification module provided with a first signal generator for generating a first frequency signal under control of a first MCU, and a first power amplifier for generating a first amplified frequency signal through the amplification of the first frequency signal under control of a first ALC circuit; a second signal amplification module provided with a second signal generator for generating a second frequency signal under control of a second MCU, and a second power amplifier for generating a second amplified frequency signal through the amplification of the second frequency signal under control of a second ALC circuit; and a triplexer module for extracting a test frequency signal using the first amplified frequency signal and the second amplified frequency signal, transmitting the test frequency signal to a device under test, and receiving a PIM signal being reflected from the device under test.

Embodiments herein achieve a method and system for selecting non-coherent spreading sequences with binary alphabets {0, 1} with variable spreading factors. The method generates circular shift equivalent sets of spreading sequences by circularly shifting base sequences with elements {1, 0} and having at least one variable spreading factor. The method determines whether each spreading sequence in the circular shift equivalent set meets pre-defined spreading sequence criteria. The spreading sequence criteria comprise balanced criteria, a non- repetition criteria, non-circular criteria, and conjugate criteria. Furthermore, the method selects the spreading sequence from expansions of at least one spreading sequence from the circular shift equivalent sets in response to determining that the spreading sequences in the circular shift equivalent sets meets the pre-defined spreading sequence criteria.