Whitepapers

Analysis of Quick Lock N Type Connectors

The N series of coaxial connector is the most widely used series for low to medium power applications in the DC to 11 GHz frequency range. The N connector is particularly well suited for applications in harsh environments or those where there is a high number of mating cycles. A relatively recent improvement has been the introduction of the Precision N connector, which operates up to 18 GHz. A major inconvenience of the traditional N connector is the threaded coupling mechanism. This has led to the invention of the Quick Lock N (QL-N) type connector, which showcases a quick disconnect feature.
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SMA Connector Frequency Extension

At the SMA connector’s inception, the operating frequency didn’t exceed 12 GHz. As the design matured, the maximum operating frequency was pushed up to 18 GHz and eventually higher. As higher operating frequencies have become common over the past several decades, other interfaces, most of which are considered precision interfaces designed for laboratory use, have been introduced to handle signal transmission at frequencies far exceeding 18 GHz. However, the SMA connector design can be optimized to extend the maximum operating frequency of the interface to offer a reliable and cost-effective solution to the higher frequency requirements of modern systems.
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Beyond Conformance Testing in 3GPP LTE

This paper describes how LTE products, systems and applications are tested in a realistic wireless environment – not in the field but in a laboratory. The benefits of beyond conformance testing compared to standard conformance testing are explained. LTE terminal and base station manufacturers as well as operators are recommended to go beyond basic testing and carry out performance measurements already in the early phases of LTE product development. The White Paper also discusses the different testing methods and introduces key radio channel models which can be used in the testing process.
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The Perils of Spectrum Analyzer Power Averaging

Averaging is a common technique for reducing the measurement uncertainty inherent in all measurements. Performing the same measurement a number of times and calculating the average of the measured values can often reduce the randomness of an experimental result. However, not all power averaging techniques give the same results. This paper dicusses the differences.
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EM Analysis within the Design Flow

Prior to the circuit design and especially in larger designs, EM tools are used to create “library” parts such as inductors, transitions and antennas. While these parts are fairly self-contained, they must ultimately be integrated into the overall design where at the very least they must be connected to the rest of the circuit or in a more complex case be coupled to it. During both early and later stages of design, designers will switch from circuit-based models to EM analysis of critical interconnects to better understand couplings and achieve greater accuracy.
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Correcting Imperfections in IQ Modulators Improves RF Signal Fidelity

This article will begin by describing a typical Zero-IF or direct-conversion transmitter along with providing a brief introduction to digital modulation. The imperfections introduced by the modulator will be examined with particular focus on the effect of temperature and frequency changes. In-Factory and In-Field algorithms that can reduce the effect of these modulator imperfections will also be discussed. Particular focus will be placed on the efficacy of In-Factory “set-and-forget” algorithms.
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Rohde & Schwarz Develops a New Technique for Group Delay Measurements without LO Access

This paper describes a technique developed by Rohde & Schwarz for the network analyzers of the R&S®ZVA family: It allows high-precision group delay measurements of converters and mixers even without access to the local oscillator or the reference signal. This technique uses a two-tone signal to stimulate the mixer or converter. The phase difference between these two carriers is measured at the input and the output of the DUT (device under test) to calculate the group delay from the phase shift caused by the DUT.
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Phase Coherent Multi-channel RF Synthesis

The phase-locked loop (PLL) has been widely used in traditional tunable RF synthesis design to maintain a “fixed” phase relationship between a generated (output) frequency and that of a reference signal. Although a properly designed PLL is an effective method for maintaining a fixed frequency, it does not allow for fully monotonic phasing in applications where phase coherence is critical.
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IP2 and IP3 Nonlinearity Specifications for 3G/WCDMA Receivers

The complete analysis of the nonlinearity requirements of a WCDMA direct conversion (Zero-IF) receiver is presented. This paper focuses on IP2 and IP3 requirements and covers all test cases defined in 3GPP, such as TX leakage, Intermodulation, Adjacent channel blocking, Narrow band blocking, In-band and Out of band blocking etc. The two tone IP2 and IP3 concept is further expanded into modulated signals. The formulas for computing IP2 and IP3 with modulated signals for different test cases are presented.
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