The concepts of signal phase modulation and signal frequency modulation, and the difference between them, are often a source of confusion. Ditto for the related idea of phase distortion. Here, we’ll try to clarify things. To understand phase distortion, recall that any waveform can be considered to be a sum of sine waves of different […]
FAQ
Difference between signal jitter and frequency modulation
Jitter and frequency modulation both involve a change in the frequency of an underlying signal. It’s worth investigating how the two phenomenon differ. Jitter is usually defined as an undesired deviation in timing of a signal from its original periodicity. It can take the form of variations in phase, period, or duty cycle. And jitter […]
Basics of amplitude distortion
Amplitude distortion is the unintended modification of a signal, typically while undergoing amplification. Amplitude modulation, in contrast, is the intended modification of a carrier wave in response to a varying audio, video or other information-bearing signal. Sources of amplitude distortion include noise and interference, but the main source is non-linear amplification. Amplitude distortion can include […]
Overview of electrical measuring instruments, Part 3
In recent columns, we’ve given a quick review of some basic instrumentation common to most engineering work benches. Here are a few more instruments found in many engineering labs. Signal generator Signal Generator is a generic term describing various instruments, all sharing a single rationale, which is that a device under test (DUT) requires a […]
More dangerous than the virus? Converting manual resuscitators to ventilators
The shortage of respiratory ventilators in the face of the Covid-19 pandemic has led to numerous efforts aimed at turning hand-operated plastic pouches called bag-valve resuscitators into makeshift ventilators. The resuscitators, also called Ambu bags, are generally on-hand in large quantities. They are designed to be operated by hand, by trained technicians, to inflate patient […]
Overview of electrical measuring instruments – Part 1
Here’s a quick review of some basic instrumentation common to most engineering work benches. Ammeter The ammeter is the basis for many other electrical measuring instruments. Whether you are measuring volts or ohms, essentially inside the instrument you are measuring current. Measurement of current in a circuit is somewhat problematic because all the electrical energy […]
Another Covid casualty: The James Webb telescope
NASA has announced it will pause work on the James Webb Space Telescope because of the ongoing COVID-19 pandemic. The launch is still currently on the books for 2021, but there are questions about whether that date will hold. The James Webb Space Telescope, successor to the Hubble and Spitzer instruments, was originally scheduled to […]
How to test for Covid-19 in 45 minutes
The FDA recently authorized use of a fast test for the Covid-19 virus that reportedly can finish up in about 45 minutes. The test was developed by Cepheid, a molecular diagnostics company that is part of Danaher Corp. The beauty of the new test is that it runs on existing Cepheid hardware called the GeneXpert […]
Can you really make a respiratory ventilator in a car factory?
Mechanical ventilators are making headlines these days because of the Coronavirus-19, widely regarded as a flu but which is actually a respiratory disease that attacks the lungs. The key to minimizing the death toll for those with virulent infections is the availability of mechanical ventilators that help people breathe when their own lungs can’t. Reports […]
How the health care system tests you for the Covid-19 virus
Engineers who usually spend a significant amount of their time around test instruments are likely spending more of it at home these days. Those of us whose working life has been interrupted by the Covid-19 virus might well begin pondering about what goes into a test for human viruses rather than those confined to computers. […]