Audio engineers in the 1970s became aware that many of the traditional distortion mitigating methods were unsatisfactory. In this context, dbx and Dolby noise reduction systems emerged. Dbx Type I and Type II vastly improved audio fidelity in analog tape reproduction. Dbx-TV is another system component that provides stereo sound for TV systems in the […]
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Attenuation networks and their measurement
An attenuator is a four-terminal, two-port network that reduces the amplitude of a signal without distorting its waveform. Attenuators are used in electronic instrumentation to precondition a signal for measurement and display. For example, the commonly-used 10:1 oscilloscope probe attenuates the signal voltage upstream from the analog channel input by a factor of ten, letting […]
The difference between LEDs and photovoltaic cells
LED’s and photovoltaic cells play increasingly prominent roles in our world. Both are semiconductor diodes. The LED or light-emitting diode emits light while the photovoltaic cell converts light to electricity. The LED is a diode that emits light only when forward-biased. Under a forward voltage bias, electrons cross from the n-region and recombine with the […]
Review: Using the Fluke 438-II motor analyzer
Fluke has come out with another superb electrical measuring instrument. It is the Fluke 438-II Motor Analyzer. Owners of the previous Fluke 435-II Power Quality Analyzer can download an upgrade that will add Motor Analyzer functions to their existing equipment. Full documentation including specifications and owner’s manuals for both of these members of the oscilloscope […]
Bit errors and ADC testing
Most engineers are introduced to the basic performance parameters of analog/digital converters in school. So specifications such as SNR, SINAD (Signal-to-noise and distortion ratio), ENOB (Effective Number of Bits), and THDA (total harmonic distortion analysis) are all familiar ADC terms found in ADC data sheets. Ditto for an INL error, described as the deviation, in […]
The difference between an electrometer and a Geiger counter
In 1895 William Roentgen observed X-rays although he could not explain their mechanism. The following year Henri Becquerel demonstrated that certain compounds of uranium emitted radiation that resembled X-rays. He showed this activity differed from the phenomenon of phosphorescence. The radiation seemed to be emitted continuously from the uranium. Did this violate the well-known principle […]
Testing Wi-Fi 6E performance
The 6 GHz band brings 1,200 MHz of additional spectrum to Wi-Fi which complicates the task of testing and verifying features. Eve Danel, LitePoint Now that the 6 GHz region of the spectrum is available for unlicensed use, Wi-Fi 6E devices are on their way to store shelves. Manufacturers face the juggling act of comprehensively […]
The difference between TDR instruments and scope-based TDR measurements
Often a transmission line is buried, concealed behind finish surfaces, or otherwise not readily accessible. So it is difficult to locate faults by means of visual inspection. It is, however, feasible to locate such discontinuities via a test instrument known as the time domain reflectometer (TDR). The TDR is sometimes compared to a radar installation, […]
ARB waveform generators and measuring amplifier gain
When it comes to amplification, the principal parameters are gain and fidelity of the output relative to the input. Gain, denoted by β (Greek letter beta), is the ratio of output voltage, current or power to input. An amplifier by definition has a power gain greater than one. Measurements that characterize amplifier gain serve as […]
The difference between testing thyristors and triacs
The thyristor is a two- or three-pin device comprised of four alternating P- and N- layers. It is also known as a silicon-controlled rectifier and is often used in light dimmer switches, speed controllers for electric motors, and switch gear for high-voltage dc power transmission systems. The thyristor does not function as an amplifier–its output […]
