| Term |
Definition |
| Accelerating voltage |
The internal voltage that accelerates the electron beam and causes trace illumination on the oscilloscope display. |
| Amplitude |
Generally defined as a measurement unit for the vertical length of a wave or signal. |
| Attenuation |
A decrease in signal amplitude, generally measured in the unit of decibels (dB). |
| Bandwidth |
The bandwidth is one of the most important specification when defining an oscilloscope as it represents the range in which an oscilloscope can display frequency accurately. The bandwidth is defined by the frequency response curve when the attenuation is at the -3dB mark. As a general rule of thumb, the oscilloscope's bandwidth should be at least five times the highest frequency of the signal under test. |
| Crosstalk |
Also known as channel isolation, is the undesired effect that a signal on a channel has on another separate channel. |
| dB |
A mathematical unit of measure, generally included as a feature in a multimeter for expressing DC and AC voltage, that minimizes the scope for a large range of measurements. It is often used to define the gain or signal-to-noise ratio. The formula to convert voltage to dB is:
dB = 20 log (Vin / Vref)
where Vin is the DC or AC voltage input and Vref is a reference voltage level. |
| Delayed Time Base |
A feature in some oscilloscopes that allows a single signal to be viewed at two different time bases with the second time base expanding a portion of the waveform and starting at some point after the main time base begins. This is often useful for magnifying display. |
| Digital Storage Oscilloscope |
An oscilloscope the digitizes the input signal before displaying it. |
| DSO |
Digital Storage Oscilloscope |
| Dual Trace |
A feature in most oscilloscopes that allow the display of two different traces, usually for comparing and analyzing more than one signal at a time. |
| Duty Cycle |
Duty cycle is a unit of measure that takes into account the ratio between the width of a pulse signal before a transition and the total time period of one pulse cycle. Pulse width period divided by pulse repetition period. |
| Edge Trigger |
A common feature found in oscilloscopes in which triggers an input signal when it detects an edge in the signal. An edge is usually the part of a waveform where there is either an increase or decrease in voltage or current level. |
| Fall Time |
The time it takes for a signal to fall from a higher level to a lower level in value. The level is often either for voltage or current. |
| Frequency |
A measurement that often defines the length of a wave and is inversely related to the period of a wave. |
| Gate Time |
In a frequency counter, the gate time is the amount of time to wait before the next frequency measurement is made. |
| Linearity |
A perfectly linear sweep would be produced by a perfectly linear sweep ramp, meaning that any variance in the sweep ramp would cause the time represented by one horizontal division on the display to be unequal to the time. |
| Period |
A measurement that often defines a full cycle of a wave before it repeats again. It is inversely related to frequency and it is measured in time. |
| PPM |
Abbreviated for Parts Per Million, literally meaning 1 PPM = 1/1,000,000. It is an alternate unit of measurement, often used in place of percentage unit for indicating resolution and accuracy. The following is a conversion list between PPM and Percent:
1 PPM = 0.0001%, 10 PPM = 0.001%, 100 PPM = 0.01%, 10000 PPM = 1%. |
| Pulse Trigger |
Defined as a triggering method that uses a pulse waveform, generally with a TTL voltage level, to signal when to trigger off a device. This is often used with an oscilloscope to trigger a waveform capture at a particular instance. |
| Ratio |
This is a measurement function found in some frequency counters to calculate the ratio of frequency between two different signals. |
| Rise Time |
The time it takes for a signal to rise from one level to another level of higher value. The level is often either for voltage or current. |
| RMS |
Is the abbreviation for Root Mean Square. It is the peak voltage of a sinusoidal waveform, times the square root of one half. |
| Sampling Rate |
Specifies the rate of which a waveform or signal is sampled. It is one of the main specifications typically defined for oscilloscopes to demonstrate the number of data samples they can display, often measured in the units of samples per second. |
| Sweep |
The motion from left to right that causes a trace to appear. For example, a sweep time of 0.1mS/div means that the trace moves from left to right across one division in 0.1mS. |
| Time Base Accuracy |
Defines the accuracy of the time base, which represents the time per division on an oscilloscope display. |
| Trigger |
Signal that causes an oscilloscope to begin sweeping across the display for a trace. This can also be considered a event in which storage process is referenced in a digital storage oscilloscope. |
| Trigger Level |
Usually set as the vertical level, in which is set to be the trigger when a trace has an amplitude that equals to or greater than it. Trigger is set off immediately when this even occurs. |
