With respect to analog signals, a “rail” is a boundary that a signal has to work within. For a long time, operational amplifiers have required opposite but equal voltage supplies. If you see a dual-supply or dual-voltage op amp, it means that two supply voltages power the amplifier; the absolute supply voltage levels are the […]
FAQ
Microcontrollers vs. Microprocessors: What’s the difference?
Microcontrollers (MCUs) tend to be less expensive than, simpler to set-up, and simpler to operate than microprocessors (MPUs). An MCU can be viewed as a single-chip computer, whereas an MPU has surrounding chips that support various functions like memory, interfaces, and I/O. The MCU vs. MPU question may seem simple, but there are some prominent […]
How IBIS models help with signal analysis
An Input Output Buffer Information Specification (IBIS) model is a standard in the semiconductor industry for modeling semiconductor devices from a behavioral perspective, for both analog and digital perspectives. IBIS modeling enables engineers to describe detailed signal behavior in a circuit design without revealing proprietary information about the circuits (or the processes used to make […]
Quantifying signal compression
The object of signal compression is to facilitate transmission, reception, processing, and the use of great amounts of data while conserving valuable storage space and transmission resources. Data compression is obviously a good approach provided that it doesn’t incur an unacceptable amount of information loss. It was once widely assumed that detail or information, once […]
Current feedback amplifiers, Part 2
Part 1 of this FAQ look at the operation of the CFB op amp and compared it to the VFB op amp. Part 2 continues the discussion of these two op amp topologies and their characteristics. Q: How do you choose between VFB versus CFB? A: Today’s CFB and VFB amplifiers have comparable performance, but […]
Basics of power cords in North America
All ac power cords sold in North America must meet a NEMA standard and UL standards that spell out factors such as the minimum wire gage and the connector style. Most cords sold for industrial use, and even many of the cords targeting home appliances, have a third contact in addition to the power and […]
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 […]
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 […]
