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Learn how to configure Rohde & Schwarz products to fit your application. Search our database by product, technology, or application to find relevant technical documents.
Search Application Notes & Cards
Learn how to configure Rohde & Schwarz products to fit your application. Search our database by product, technology, or application to find relevant technical documents.
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This application note has been replaced by application note .
27-Oct-2009 | AN-No. 1MA56
A high frequency transformer is a key component when designing isolated switching mode power supplies (SMPS). Leakage inductance is essential in the control of many design parameters including efficiency, maximum voltage rating for switching elements and EMI when it comes to designs using customized transformers. Accurate measurement of this parasitic element is mandatory. The R&S®LCX LCR meter is ideal for this challenging measurement task.
15-Feb-2022
This document is divided in two parts and starts with an introduction in AC-DC conversion principles in general. It will present the most common circuits used for different power levels. The switching mode power supply (SMPS) converter will be the main focus as they are used everywhere in the electronics. Especially the flyback converter design in different flavors are highlighted. Nevertheless, all measurements are also applicable for other SMPS converter designs operating at higher power levels.In the second part of this document, most relevant testing methods and procedures of an AC-DC converter are highlighted. For each testing section, a fundamental part will be upfront discussed and it is followed by a presentation of a suitable measurement method. In this second part, the device under test (DUT) is considered as black box device and thus the structure is similar. Therefore, the testing parts consists of methods related to input tests, output tests and a combination of both like efficiency. Of course, some test performed at the output of the converter are also relevant for DC-DC converter, e.g. the validation of the output ripple.
14-Nov-2022 | AN-No. 1SL387
Almost every switched-mode power supply (SMPS) needs an EMI (Electro Magnetic Interference) input filter to suppress any disturbances of the SMPS on the power lines. This requirement having an input filter in the design ensures that no negative effect will occur in other parts of the systems connected to the power lines. Therefore, the design and the validation of the input filter is a major task during a typical power supply design. The conducted emission (CE) test according to a specific standard is a suitable and a common validation method to release the design at the end of the development cycle. Nowadays, this conducted emission test will be performed as pre-compliance test during the development phase in the lab as well. In this case, the designer will obtain an early feedback whether the design has to be optimized regarding any disturbances present on the power lines. In most cases, the designer has to adjust the input filter to obtain a more effective suppression of disturbances generated by the SMPS. However, the designer needs to know details about the noise spectrum to optimize the input filter as effective as possible. In addition to magnitude and frequency information of the noise source, it would be very helpful to know whether the noise is generated by a common mode source or by a differential mode source. During the standard conducted emission test, common and differential mode noise is a combination in the measurement results and thus not possible to gain deeper insights. This document will describe a method to separate common-mode and differential-mode separation using two oscilloscope channels. This separation approach works without any additional hardware component like a noise separator. The designer will be able to distinguish between common-mode (CM) and differential-mode (DM) noise. This additional information about the dominant mode provides the capability to optimize input filters very efficiently.
17-Sep-2020 | AN-No. GFM353
Oscilloscopes are the workhorses for power electronics engineers. With powerful and easyto- use FFT analysis capabilities, their application fields extend to EMI debugging – and that saves a lot of time and money. A typical task is verifying the effectiveness of an EMI filter – early in the development phase.
23-Sep-2019
Modern, capacitive touchscreens as used, for example, in mobile phones are susceptible to common mode noise exhibited by external power supplies (EPS).
17-May-2018
A Test Port Adapter System is implemented for all Rohde & Schwarz equipment, which operates above 26 GHz in order to protect the RF front-end from mechanical damage. The Test Port Adapter System consists of an RF front-end interface called the Test Port Adapter Body, and the Test Port Adapter Head which is attached to the Body. The Head provides an interface to a cable or device under test. This Application Note identifies the various types of Test Port Adapters, their parameters, compatibilities and usages.
28-Apr-2015 | AN-No. 1MA100
The use of Rohde & Schwarz device drivers under VEE software is not complicated. However, a number of factors are involved, the errors that occur are often difficult to diagnose. This application provides easy and detailed support for installation and troubleshooting using National Instruments or Agilent GPIB boards.
20-Dec-2012 | AN-No. 1MA035
This paper describes the characterization of aluminum electrolytic capacitors specifically used in AC-DC power converter applications. It will be discussed why this capacitor technology is critical regarding lifetime and why it cannot be substituted simply by any another capacitor technology. Different aging effects of the capacitor will be discussed. Usage of the capacitor in different AC-DC converter topologies will be presented. Simulation circuits will be used to analyze the capacitor in more detail before suitable measurements will be performed to demonstrate a real example of a switching-mode power supply (SMPS).After the introduction into the aluminum electrolytic capacitor basics and theory, this paper will also present all important and possible measurements of capacitor parameters, like capacitance, equivalent series resistance (ESR) and ripple current. This includes in-circuit measurement which can be performed with an oscilloscope. An LCR-bridge is used to obtain high accuracy measurements in addition. A comparison between the two measurement methods will be presented. Furthermore, the required measurement hardware for the in-circuit measurements and the bridge measurement will be discussed and presented.Lastly, two different lifetime calculation methods are presented and a real example is used to compare the advantages and disadvantages of the different methods.Thanks to Mr. Frank Puhane from Würth eiSos GmbH & Co. KG who provided me with all aluminum electrolytic capacitor samples including the prepared capacitor with build-in temperature sensors to perform all measurements. Furthermore, his great expertise was very beneficial and helpful to create this premium application note.
07-Feb-2023 | AN-No. 1SL388