Accuracy - The percentage of error possible in transferring the signal through the vertical and horizontal amplifiers.
Averaging - A process of reducing random noise in a signal by taking a number of waveform recordings then displaying the average value.
Auto Trigger - A trigger signal generated internally by the DSO that starts the scope capturing data. (See Trigger, Normal Trigger)
Bandwidth - The maximum frequency the scope will accept without reducing the amplitude by more than 3 db (or 70%).
Bit Accuracy - The accuracy of the sampling system usually quoted as ENOB - Effective Number Of Bits.
Common Mode Voltage - The average voltage of the two inputs.
Common Mode Voltage Range - The maximum common mode voltage which will be rejected.
Common Mode Rejection Ratio - How well the common mode voltage is cancelled at different frequencies. 60dB means that 10V of common mode voltage results in 10mV at the oscilloscope input.
20 x log (10V/10mV) = 60dB
Cursors - Markers that allow accurate measurements to be made of signal times and amplitudes.
Digital Bandwidth - The Nyquist Theory states that at least two samples are needed to determine a frequency, thus the highest frequency determinable is SR/2. This is known as Digital Bandwidth.
Digitizing Rate - The speed at which the analog to digital converter samples the incoming waveform. Usually specified in MegaSamples per Second.
Envelope Mode - A scope mode where the excursions of the waveform can be stored on the screen.
Equivalent Time Sampling - Equivalent time sampling (ets) sometimes termed random time sampling is a method of obtaining a high sample rate. The acquisition is built over time by moving the trigger point randomly by very small amounts with successive timebase sweeps.
Event Triggering - The ability to trigger on a single event in a pulse stream.
Falltime - The time for a falling edge to pass from typically 10% to 90% of its amplitude.
FFT (Fast Fourier Transform) - A mathematical technique for changing the format of waveform data from amplitude vs. time information to amplitude vs. frequency (frequency domain).
Glitch Detect - A sample and hold circuit that allows the maximum and minimum signal excursions occurring between samples to be stored and displayed.
Horizontal Resolution - Time resolution determined by the A/D sampling rate; on a DSO plus or minus one sample interval.
IEEE-488.2 (GPIB) - An industry standard instrument bus that allows control information and data to be passed to and from the DSO.
Interpolation - A method of reconstructing the waveform by connecting the sample points with a mathematical algorithm to provide a 'better look' to the signal shown on the screen.
Logic Triggering - A method of triggering the DSO from a group of logic channels (usually a data word or address).
Memory Depth - The number of samples the DSO takes each time a waveform is digitized and displayed.
Normal Trigger - Where the scope is triggered only with a valid signal from the specified source. (See Trigger, Trigger Source, Auto Trigger)
Offset - A DC voltage which can be injected into one of the inputs to cancel some of the differential signal.
Persistence Mode - A method of continually storing consecutive traces on the DSO screen (similar to an analog storage oscilloscope).
Risetime - The time for a falling or rising edge to pass from typically 10% to 90% of its amplitude. Risetime is directly related to the bandwidth as follows; Risetime (in ns) = 350 / Bandwidth (in MHz)
Record Length - (See Memory Depth)
Refresh Display - The display is updated from left to right across the screen.
Repetitive Sampling - A technique of increasing the sample rate of the scope by digitizing consecutive waveforms. (See also Digitizing Rate)
Resolution - (see Vertical Resolution, Horizontal Resolution)
Roll Display - The display is updated from right to left across the screen.
Sample Rate - (See Digitizing Rate)
Screen Update Rate - The number of times per second that the screen information is renewed. The quicker the rate the better the feel of the DSO controls
Segmented Memory - The memory can be divided into segments and capture successive events. It gives the ability to capture several events in the memory.
Sequence - A sequence of control operations. These can be stored and repeated for automatic operation.
Sensitivity - The range of voltages that an input can accept.
Sweep Speed - (See Timebase)
Timebase - The horizontal axis of the DSO calibrated in Time per Division.
Trigger - The signal that tells the DSO to start capturing data.
Trigger Coupling - The method of connecting the trigger circuit to its source. Usually DC, AC, filtered or TV synchronized.
Trigger Source - The signal source used to trigger the scope. Usually one of the input channels or an external input. (See Normal Trigger, Auto Trigger)
Vertical Resolution - The number of digitizing levels from the analog-to-digital converter. 8 bit resolution provides 256 steps, 6 bit resolution, 64 steps.
X -Y Display - The display is proportional to separate voltage inputs in both vertical and horizontal.
Z Modulation - A term applicable to real-time oscilloscopes not used with DSOs. It is the control of the display brightness and is used to mark points of interest usually in X - Y applications.