Analog-to-digital converters (ADCs) need a reference voltage (VREF) input in order to operate properly. ADCs convert analog inputs that can vary from zero volts on up to a maximum voltage level that is called the reference voltage. The reference voltage determines the ceiling of what the ADC can convert, and is essentially the yardstick against […]
FAQ
Difference between fixed and floating point
Various types of processors (DSPs, MCUs, etc.) have the ability to do math using floating point numbers, but what exactly does this mean? In general, floating point math offers a wider range of numbers and more precision than fixed point math. Knowing the difference, and when to use which type of math can make a […]
Eye and Constellation Diagrams, Pt 2
Part 1 looked at the eye diagram, a simple yet powerful visual tool which reveals many specifics about the quality of a recovered bit stream. Part 2 looks at the constellation diagram, another powerful visual tool which is used to show the signal space of complex encoding schemes and relationship among the symbols. Q: Why […]
Measuring with spectrum analyzers
Modern bench-type and even hand-held oscilloscopes have spectrum analysis capability, providing great added versatility. They can view in rapid succession (or even simultaneously in split-screen format in a mixed-domain instrument) time domain and frequency domain displays of the same signal. Fourier theory tells us that any signal or function in the time domain can be […]
Difference between a brushless dc motor and a shaded pole induction motor
Motors that power cooling fans tend to be either brushless motors or induction motors. Here we examine the key differences in the construction of these two motor types and explain the reason for the striking differences in energy efficiency between the two types. Brushless motors are sometimes called electronically commutated motors. Here commutation refers to […]
Measuring antenna properties
An antenna is simply a conductor or conductor array, usually metal. But how it is situated and terminated that determines its behavior in transmitting and/or receiving electromagnetic radiation. Let’s start with an antenna that is configured to transmit. An oscillating voltage applied at a terminal will cause current to flow through the antenna. A transmitting […]
Learning SMPS the hard way
By Tahmid, EDAboard.com forum member SMPS is the toughest section in power electronics. For this subject, you require additional knowledge for choosing the active and passive parts used in SMPS circuits. The special type of parts often required in power electronics (i.e. for low-frequency applications) may not be suitable in the case of SMPS. When […]
Eye and Constellation Diagrams, Pt 1
Digital signals representing data symbols may be presumed to be clean, consistent representations of ones and zeroes when they are launched onto their communications medium, whether it is a wired, wireless RF, or optical fiber link. However, due to bandwidth limitations of the medium, external and internal noise, crosstalk, multipath, reflections, and many other unavoidable […]
Expanding I/O with MUX, DEMUX, and decoders
The relentless march of technological progress has given engineers increasingly smaller and more energy efficient microcontrollers to use in their designs. These benefits do come with a cost, however. Physically smaller packages have less room for I/O pins meaning fewer peripheral components can interface with the microcontroller itself. Fewer peripherals means less functionality which tends […]
Choosing a reference voltage for an ADC
Analog-to-digital converters (ADCs) need a reference voltage (VREF) input in order to operate properly. ADCs convert analog inputs that can vary from zero volts on up to a maximum voltage level that is called the reference voltage. The reference voltage determines the ceiling of what the ADC can convert, and is essentially the yardstick against […]