White Papers

A Reconfigurable, Digital Multi-band SATCOM Terminal: Closer Than You Think

Conventional analog RF transceiver implementations have many performance limitations that include RF frequency dependency, non-linearities, high insertion losses, circuit tuning requirements and expensive inter-connections that ultimately bound the performance of the complete earth terminal. These limitations are greatly multiplied when operational scenarios call for multiple frequency bands, multiple beams and multiple channel configurations. These analog RF channel designs are highly frequency dependent and not optimized for an OSA. As a result, multi-band SATCOM terminals are often found to be complex and costly. An all-digital RF implementation can potentially solve these problems as it can provide a highly linear digital RF signal distribution system and can provide multiple band, frequency and channel operation within a single integrated product.
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Analysis of Nonlinear Active Devices Including True Balanced Differential Measurements

VNAs have been the workhorse of microwave measurements for many years. They provide the ability to measure S parameters of active and passive devices and systems. When measuring active devices, these measurements are made on small signal devices where gain is linear. When measuring small signal amplifiers, the linear VectorStar VNA provides many built-in functions to thoroughly analyze these active devices. Applications such as built-in programmable power sweeps for gain compression analysis at multiple frequency points, IMD measurements, harmonic measurements, characterization down to 70 kHz to evaluate memory effects, etc., are all available in the VectorStar VNA. Table 1 provides a brief overview of the capabilities of the MS4640A family of VectorStar VNAs.
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R&S MATLAB® Toolkit for Signal Generators and Power Sensors

MATLAB is widely used for the simulation of communication systems as well as for the creation or analysis of custom signals. The MATLAB Toolkit provides functions that link the Rohde & Schwarz instruments to the MATLAB environment. For this purpose the toolkit contains scripts for the most common tasks, such as instrument remote control and data transfer.
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MIMO Over-the-Air Testing

Traditional conducted-signal testing of mobile devices provides a more repeatable testing environment than testing with a radiated signal. However, the planned evolution of Fourth-Generation (4G) wireless technologies is critically dependent on Multiple-Input Multiple-Output (MIMO) antenna configurations, which promise significant data-rate increases based on moderate increases in complexity. Therefore, an over-the-air (OTA) testing methodology is needed to account for antenna behavior within the device evaluation.
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Solutions for Characterizing High-power Devices

High-power devices are common building blocks in RF and microwave communication systems. One such device, the high-power amplifier, plays an especially critical role in today’s mobile phones, base stations for cellular and mobile wireless infrastructure and satellite communication systems. In the base station market, for example, high power amplifiers approaching 100 watts are typical. To obtain the most power from these devices, engineers are forced to push them to their limit, often driving them into the nonlinear region of operation. Such nonlinear behavior can be problematic to the amplifier and is typically a contributing factor in wasted frequency spectrum in communication applications. Accurately characterizing and understanding this behavior is critical to enabling today’s engineer to design and verify efficient high-power devices like amplifiers.
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