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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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In general, most of the existing electronic devices are connected to the AC mains and require a power conversion stage to convert the AC-Voltage to a smaller DC-Voltage. Voltages and frequencies of the power grid differ between different regions. However, different types of AC-DC conversion stages exist to supply the electronic equipment with adequate DC-power.In AC-DC conversion combined with power levels less than 50W, the flyback converter is a commonplace chosen topology because of its simplicity and its low cost. The majority of consumer products make use of this converter type like wall brick power supplies or power adapters for any consumer application and other type of stand-by auxiliary power supply like used in white and brown goods. In AC to DC converter application, an electrical isolation between input and output is mandatory. The flyback topology provides this galvanic barrier.Beside the common advantages of a flyback converter, it has inherently parasitic components, which typically produce ringing waveforms with considerably high voltage spikes. Without suppressing this unwanted ringing, it may have some negative effect on other components like the switching elements. This ringing can also influence the EMI emissions adversely. Therefore, it is an important task to adequate suppress and damp the ringing effect. This damping circuit is known as snubber circuit and provides this functionality. In the flyback converter, different snubber structures can be applied and each of the structure has its advantage and disadvantage.The demand having a snubber circuit in the power supply topology leads to specific verification methods during the design to obtain a proper and reliable design. These verification methods are the main focus of the discussions within this document.
23-Jun-2021 | AN-No. 1SL363
Solutions and Tipps for NR FR1 in TDD Downlink Mode
5G New Radio (NR) is a radio technology specified by 3GPP and was first released in 3GPP release 15. It is designed to target three use cases, i.e. enhanced mobile broadband (eMBB), massive machine type communication (mMTC) and ultra-reliable low latency communication (URLLC). Among these three use cases, eMBB represents actually a further evolution of mobile broadband communication from LTE standard. According to the technical performance requirement defined by IMT-2020, by deploying 5G technology, peak data rates of eMBB application are expected to reach 20 Gbps in downlink (DL) and 10 Gbps in uplink (UL) direction, respectively. Typical use cases of eMBB are data hungry applications, such as high resolution 8K video streaming, virtual reality (VR), augmented reality (AR) etc.Verification of a 5G capable user equipment (UE) with respect to its achievable maximum data throughput under controllable and deterministic test conditions is an essential process during the design phase of the product. Performance centric verification through identification of the data throughput bottleneck, product benchmarking against a golden device enhances tremendously the user experience in the end.This document focuses on 5G NR frequency range 1 (FR1) with TDD duplex mode in E-UTRAN New-radio Dual Connectivity (ENDC) operating mode. As 5G NR physical layer offers a plethora of flexibility, the motivation here is to provide a kind of guideline of relevant parameter settings to stimulate device under test (DUT)'s max throughput capacity. The status quo of the R&S solutions at the time when the application note is created are described. Shown feature sets are constantly evolving, so the screenshots used and the parameters shown may change.
07-Jul-2022 | AN-No. 1SL379