Antennas based on fractal mathematics offer some significant advantages but also some controversy. The first part of this article looked at the basic concept and history of fractals. This part looks at the relationship between fractals and antennas. Q: All this fractal discussion is interesting, but what does it have to do with antennas? A: […]
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FAQ on fractal antennas, Part 1
Antennas based on fractal mathematics offer some significant advantages but also some controversy. Although all antenna designs are derived from either the basic dipole or monopole/ground-plane configurations, there are almost countless antenna variations in use (Figure 1). Each one offers a different combination of key attributes such as center frequency, bandwidth, bandwidth, side lobes, front-to-back […]
Zero-drift amplifiers finesse ultralow-frequency signals, Part 3
Modern zero-drift amplifiers provide the extremely low drift and noise performance, needed for processing many optical biological, and physical-world signals near 0 Hz. Contrary to what you might think, mechanical chopping is still alive and useful. Given the outstanding performance of electronic components, using a high-performance zero-drift amplifier seems the way to go. That is […]
Zero-drift amplifiers finesse ultralow-frequency signals, Part 2
Modern zero-drift amplifiers provide the extremely low drift and noise performance needed for processing many optical biological, and physical-world signals near 0 Hz. The ultimate limitations of chopping led designers to investigate another approach called auto-zeroing, which is especially feasible with integrated circuits. This is a dynamic correction technique that works by sampling and subtracting […]
Zero-drift amplifiers finesse ultralow-frequency signals, part 1
Modern zero-drift amplifiers provide the extremely low drift and noise performance needed for processing many optical biological, and physical-world signals near 0 Hz. In our world of ever-faster, wider-bandwidth signals and systems operating at higher and higher frequencies, it may seem that signals in the very-low-frequency range — down towards zero hertz (0 Hz) — […]
When to buffer and when to drive signals
Buffers and drivers both provide impedance transformation between the input and output. The differences begin to appear when looking at the common types of buffers and drivers, for example, voltage and current buffers, clock buffers, line drivers, and gate drivers. Basic buffers and drivers have one input and one output, but there are others that […]
How to specify and use analog switches
An analog switch is an IC that can be used to control connections to analog and digital signals. These switches provide bidirectional connections when “on” and high impedance paths when “off.” There’s a wide range of analog switches for special functions. In some instances, they are used in place of mechanical switches. In other embodiments, […]
How do comparators and op amps compare?
Operational amplifiers (op amps) and comparators have two inputs, inverting and noninverting, and an output that can usually swing from rail to rail and have the same schematic symbol. So, what’s the difference? This FAQ compares the two devices and digs into some of the similarities and differences. It begins with a top-level comparison of […]
How to specify and use voltage references
Voltage references are small components that can have a significant impact, either positive or negative, on system performance. They are precision devices that maintain a constant voltage output even in the presence of changes in temperature, input voltage, and other external parameters. When measuring the analog world, voltage references ensure that data converters, detection circuits, […]
What’s the difference between transceivers and transponders?
Transceivers and transponders are types of communication devices. They can operate with RF or optical technologies. They are used in various environments, from terrestrial to undersea and outer space. Basic transceivers and transponders provide two-way links in various types of networks. Specialized devices like muxponders increase available bandwidth, extend network reach and improve network efficiency. […]
