A~O                P~Z

Oscilloscope Terminology (A~O)
AC: Alternating current; an electric current that reverses its direction at regularly recurring intervals.

ADC: (Analog-to-Digital Converter) an electronic device which converts analog signals to an equivalent digital form, in either a binary code or a binary-coded-decimal code. When used for dynamic waveforms, the sampling rate must be high to prevent aliasing errors from occurring.

ADC Resolution (Or Vertical Resolution): The resolution, in bits, of the ADC (and therefore the digitizing oscilloscope) indicates how precisely it can turn input voltages into digital values.

Address: The label or number identifying the memory location where a unit of information is stored.

Aliasing: If the sample rate of a function (fs) is less than two times the highest frequency value of the function, the frequency is ambiguously presented. The frequencies above (fs/2) will be folded back into the lower frequencies producing erroneous data.

Alternate Mode: A display mode of operation in which the oscilloscope completes tracing one channel before beginning to trace another channel.

Amplitude Modulation (AM): Where audio signals increase and decrease the amplitude of the "carrier wave".

Amplitude: 1) The magnitude of a quantity or strength of a signal. In electronics, amplitude usually refers to either voltage or power. It is the highest value reached by voltage, current or power during a complete cycle.  

Amplitude Span: The Y-axis range of a graphic display of data in either the time or frequency domain. Usually a log display (dB) but can also be linear.

Analog Oscilloscope: An instrument that creates a waveform display by applying the input signal (conditioned and amplified) to an electron beam moving across a CRT screen. A chemical phosphor coated on the CRT creates a glowing trace wherever the beam hits.

Bandwidth: A frequency range.

Chop Mode: A display mode of operation in oscilloscope in which small parts of each channel are traced so that more than one waveform can appear on the screen simultaneously.

Circuit Loading: The interaction of the probe and oscilloscope with the circuit being tested, distorting the signal.
Clipping: The term applied to the phenomenon which occurs when an output signal is limited in some way by the full range of an amplifier, ADC or other device. When this occurs, the signal is flattened at the peak values, the signal approaches the shape of a square wave, and high frequency components are introduced. Clipping may be hard, as is the case when the signal is strictly limited at some level; or it may be soft, in which case the clipping signal continues to follow the input at some reduced gain.

Compensation: A probe adjustment for 10X probes that balances the capacitance of the probe with the capacitance of the oscilloscope.

Complex Wave: The resultant form of a number of sines, squares, steps, and pulses to produce a wave that is summed together forming a periodic wave. . The signal information may be embedded in the form af amplitude, phase, and/or frequency variations.

CRT: Cathode-Ray Tube. An electron-beam tube in which the beam can be focused on a luminescent screen and varied in both position and intensity to produce a visible pattern.

Cursor: An on-screen marker that you can align with a waveform to take accurate measurements.

Cut-off Frequency: The frequency at which the gain or amplification is unity.

Damping: The reduction of vibratory movement through dissipation of energy. Types include viscous, coulomb, and solid.

dB(Decibel): 20 times the log to the base 10 of the ratio of two voltages. Every 20 dBs correspond to a voltage ratio of 10, every 10 dBs to a voltage ratio of 3.162. For instance, a CMR of 120 dB provides voltage noise rejection of 1,000,000/1. An NMR of 70 dB provides voltage noise rejection of 3,162/1.

Division: Measurement markings on the CRT graticule of the oscilloscope.

Digital Storage Oscilloscope (DSO): An oscilloscope that acquires signals using an analog-to-digital converter(ADC). It uses a serial architecture that employs a single processor to control acquisition, user interface, and the raster display.
DSP : Digital Signal Processing

Earth Ground: A conductor that will dissipate large electrical currents into the Earth.

Effective Bits:  It is the measure of the a DSO's ability to accurately reconstruct a signal by considering the quality of the oscilloscope's ADC and amplifiers.

Envelope: The outline of a signal's highest and lowest points acquired over many repetitions.

Equivalent-time Sampling: A sampling mode in which the oscilloscope constructs a picture of a repetitive signal by capturing a little bit of information from each repetition.

Focus: The oscilloscope control that adjusts the CRT electron beams to control the sharpness of the display.

Gain Accuracy: The gain accuracy indicates how accurately the vertical system attenuates or amplifies a signal. This is usually listed as a percentage error.

Glitch: An periodic error in a circuit.

Graticule: The grid lines on a screen for measuring oscilloscope traces.

Harmonic: A sinusoidal component of a waveform that is a whole multiple of the fundamental frequency. An oscillation that is an integral sub-multiple of the fundamental is called a sub-harmonic.

Noise: An unwanted voltage or current in an electrical circuit.

Oscilloscope: An instrument used to make voltage changes visible over time. The word oscilloscope comes from "oscillate," since oscilloscopes are often used to measure oscillating voltages.