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We’re all familiar with the general idea of a filter: it removes something that we don’t want from something we do want. Coffee filters that pass the liquid coffee but retain the grounds or air filters that pass clean air but trap the dust and other pollutants are two common examples of mechanical filters in everyday life. That same concept can be applied to noisy electrical signals to pass through the “true” signal of interest while blocking the undesirable noise signal. Looking at Figure 2.5c below, imagine for a moment that the signal of interest is in the lower-frequency region and that the noise signal is in the higher-frequency region. Ideally, we’d like to be able to get rid of that high-frequency noise, leaving just the signal component that we want.

Harmonic balance (hB) analysis is a method used to calculate the nonlinear, steady-state frequency response of electrical circuits. It is extremely well-suited for designs in which transient simulation methods prove acceptable, such as dispersive transmission lines in which circuit time constants are large compared to the period of the simulation frequency, as well as for circuits that have a large number of reactive components. In particular, harmonic balance analysis works extremely well for microwave circuits that are excited with sinusoidal signals, such as mixers and power amplifiers...

A shielded transformer is a two-winding transformer, usually delta"star connected and serves the following purposes: Voltage transformation from the distribution voltage to the equipment's utilization voltage. Converting a 3-wire input power to a 4-wire output thereby deriving a separate stable neutral for the power supply wiring going to sensitive equipment. Keeping third and its multiple harmonics away from sensitive equipment by allowing their free circulation in the delta winding. Softening of high-frequency noise from the input side by the natural inductance

The consumer handheld market is growing by leaps and bounds. With more processing power and increased support for more applications, portable products are cross-pollinating with traditional computing systems even as the product life cycle has decreased considerably in this market segment. As a result, especially in this era of economic slowdown, it is imperative that new products meet the time-to-market window to gain maximum acceptance. A decrease in product life cycles requires a reduced development cycle and an increased emphasis on reusability and reprogrammability. The emerging handheld market is also seeing interesting trends in which each individual device in a family has lower volumes but there is more customization across the series of devices, effectively upping the total unit volumes. The key challenge then becomes how to develop a system that is widely reusable and also customizable. These requirements have led designers increasingly to turn to the FPGA for handheld-product development. The FPGA has become more powerful and feature-rich, while gate counts, area and frequency have increased. FPGA development and turnaround cycles are considerably shorter than those of custom ASICs, and the added advantage of reprogrammability can make the FPGA a more compelling solution for handheld embedded systems.

NXP BV (Eindhoven, The Netherlands) has said it will demonstrate a microcontroller based on the ARM Cortex-M4 at the Embedded Systems Conference in San Jose, California. NXP was one of the first companies to license the Cortex-M4 processor core and a chip has been implemented using a low-leakage 90-nm process technology. This enables performance in excess of 150-MHz clock frequency, NXP said. NXP has added proprietary power-down techniques to reduce power consumption. The ESC Silicon Valley demo will show that a 7-channel audio graphic equalizer application processing 32-bit precision audio data requires only 12 MHz of CPU bandwidth using the Cortex-M4 DSP extensions, and 60 MIPs without. The core includes DSP extensions not usually found inside a microcontroller and NXP's implementation are aimed at a broad set of applications including motor control, digital power control and embedded audio.

ON Semiconductor has expanded its multiplexer product line with devices that are designed to function at high input rates/clock frequencies. The NB6VQ572M, NB6LQ572, NB7L572, NB6L572M, NB7LQ572, NB6LQ572M, NB7VQ58M and NB7V58M mux/fanout devices are targeted at SONET, Gigabit Ethernet, Fiber Channel, backplane and other clock/data distribution applications. The NB6VQ572M and NB6LQ572M differential 4:1 clock/data input multiplexers with 1:2 current mode logic (CML) clock/data fanout buffers operate at up to 6 GHz/8 Gbps from a 1.8 V, 2.5 V or 3.3 V power supply. The new devices have a data dependent jitter of <10 ps and random clock jitter of less than 0.8 ps RMS.

Linear and nonlinear device models are costly and time-consuming to develop. Most compact model parameters are extracted from linear, 50-ohm S-parameters and predicting behavior under extreme nonlinear conditions or non-50 ohm terminations is unreliable. This white paper entitled "X-parameters and Beyond, AWR's Support of PHD and Nonlinear Behavioral Models," provides details on rapidly-emerging nonlinear models and measurement systems and how Thye are employed in AWR's Microwave Office high-frequency design software.