Passive intermodulation (PIM) is a critical issue in wireless communication systems, where the increasing demand for voice and data transmission within fixed bandwidths has made PIM a major limiting factor for system capacity. In active devices, when signals of two or more frequencies mix nonlinearly, they generate spurious signals known as passive intermodulation. These unwanted signals can fall within the uplink frequency band of a base station, causing receiver desensitization, which degrades call quality or reduces the carrier-to-interference ratio (C/I), ultimately lowering the system’s overall capacity.
PIM can arise from various factors such as poor mechanical contact, iron-containing conductors in the RF path, or surface contamination on RF components. Predicting PIM values accurately is challenging, and measured results are often used to approximate device performance. Minor changes in design or manufacturing can significantly affect intermodulation levels, prompting some manufacturers to perform 100% testing to ensure compliance with PIM specifications.
In this article, we focus on the integrated cable, one of the key components in high-power transmission channels that can produce intermodulation distortion. The intermodulation response of these cables is both directional and frequency-dependent, making it an essential consideration for their use in base stations.
To measure intermodulation in integrated cables, the Summitek SI-1900A Passive Intermodulation Analyzer is used. This device allows for simultaneous measurement of forward and reverse intermodulation responses without requiring reconnection, reducing errors caused by repeated connections. The test setup involves injecting two high-power signals into the cable through port 1, while port 2 acts as a load. The reflected and transmitted intermodulation responses are then measured at ports 1 and 2 respectively.
A model is introduced to help understand the reflection and through intermodulation behavior of the cable. In this model, the intermodulation is assumed to occur only at the joints of the cable, with the rest of the cable acting as a linear transmission medium. By considering the intermodulation sources at both ends and their propagation through the cable, the model provides insights into how different intermodulation responses interact and affect the overall measurement.
Using this model, engineers can predict the intermodulation characteristics of integrated cables and better interpret field or lab measurements. The model also highlights that the intermodulation response depends on factors like cable length, frequency, and environmental conditions such as temperature, which can alter the electrical length and phase relationships between intermodulation sources.
In conclusion, the simplified model effectively predicts the reflection and through intermodulation of integrated cables. While discrepancies between predicted and measured results may exist due to real-world complexities, these differences can be explained and accounted for. Engineers can use these findings to optimize system performance, manage PIM issues, and improve the reliability of wireless communication networks.
1. Capacitor testing industry: The main products are capacitor leakage current ripple test power supplies used for capacitor life and quality testing. It is an industrial power supply product mainly adopted by capacitor manufacturers` for products quality control or capacitor use manufacturers` for sourcing capacitor inspections with current endurance life test, according to the variety of output voltage and frequency required for different capacitance tests, the DC output voltage of this power supply is up to 3000V, the AC voltage output is up to 400V, the AC current is up to 400A, and the output frequency can be 50Hz-100KHz according to customer requirements.
2. Capacitor aging industry: The main products are our first-generation high-power DC power supply products, based on the development of IGBT-based hard-switching technology, with high output accuracy, low ripple, high efficiency, fast response speed and good cost advantages, the power supplies are featured with constant voltage, constant current working mode automatic switching function, overvoltage protection circuit, overheat protection circuit, short circuit protection function. For the convenience of industry users, this power supply can also add customized functions, such as: automatic shutdown for load discharge function, overvoltage, overcurrent protection value preset and view function and pulse aging function, etc., to adapt to the use of sophisticated capacitors of capacitor manufacturers.
3. Surface treatment industry: The DC rectifier based on the high frequency switching technology of IGBT switching devices is a product developed by our company for industrial applications such as electroplating, electrolysis, water treatment, and hard oxidation. There is no mandatory requirement for output ripple in this industry application. So, this industrial power products do not put too much LC circuit processing to the input and output ends. It has high requirements for output current stability and long-term operation capability, mostly low-voltage and high-current output, up to 2000KW, with ultra-high DC output of 50000A.
To overcomes the harsh application environment and long-term operating conditions. The industrial power supplies basically adopt water cooling, and the internal components of the power supplies are treated with three preventions, which can realize the effective heat dissipation and effective protection of internal devices of the power supply.
The above-mentioned industrial power products can accept customized production requirements without minimum order quantity restrictions.
Industrial power supplies are power products specially designed and produced for a certain industrial production industry. For industrial power supplies, absolute balance of electronics characteristics is not the main focus. Different industrial applications focus on different specific electronics index, some focus on the stability of the power supply output voltage or current, but the ripple is not the key judging criteria; some industrial applications have customized requirements for power supplies, such as adding time control, adding pulse functions, adding multiple outputs, etc. At the same time, it is necessary to consider the cost requirements of large-scale purchases of industrial applications, so for industrial power supplies, Application adaptability, Long-term operating Reliability and Reasonable cost control are the main points of attention for industrial power supplies.
1. Capacitor testing industry: The main products are capacitor leakage current ripple test power supplies used for capacitor life and quality testing. It is an industrial power supply product mainly adopted by capacitor manufacturers` for products quality control or capacitor use manufacturers` for sourcing capacitor inspections with current endurance life test, according to the variety of output voltage and frequency required for different capacitance tests, the DC output voltage of this power supply is up to 3000V, the AC voltage output is up to 400V, the AC current is up to 400A, and the output frequency can be 50Hz-100KHz according to customer requirements.
2. Capacitor aging industry: The main products are our first-generation high-power DC power supply products, based on the development of IGBT-based hard-switching technology, with high output accuracy, low ripple, high efficiency, fast response speed and good cost advantages, the power supplies are featured with constant voltage, constant current working mode automatic switching function, overvoltage protection circuit, overheat protection circuit, short circuit protection function. For the convenience of industry users, this power supply can also add customized functions, such as: automatic shutdown for load discharge function, overvoltage, overcurrent protection value preset and view function and pulse aging function, etc., to adapt to the use of sophisticated capacitors of capacitor manufacturers.
3. Surface treatment industry: The DC rectifier based on the high frequency switching technology of IGBT switching devices is a product developed by our company for industrial applications such as electroplating, electrolysis, water treatment, and hard oxidation. There is no mandatory requirement for output ripple in this industry application. So, this industrial power products do not put too much LC circuit processing to the input and output ends. It has high requirements for output current stability and long-term operation capability, mostly low-voltage and high-current output, up to 2000KW, with ultra-high DC output of 50000A.
To overcomes the harsh application environment and long-term operating conditions. The industrial power supplies basically adopt water cooling, and the internal components of the power supplies are treated with three preventions, which can realize the effective heat dissipation and effective protection of internal devices of the power supply.
The above-mentioned industrial power products can accept customized production requirements without minimum order quantity restrictions.
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Yangzhou IdealTek Electronics Co., Ltd. , https://www.idealtekpower.com