Specifications

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bandwidth
In the context of oscilloscopes, this is the upper frequency rating of the
oscilloscope's vertical amplifier(s) (the scope's lower frequency rating is 0 Hz,
as it can measure DC voltages). The rating is usually the 3 dB point, which
means the measured amplitude of a constant-amplitude sine wave is 3 dB
below that of a lower frequency sine wave of the same amplitude at, say, half
of the bandwidth.
blanking
In an analog scope with a CRT, this is the process of turning off the electron
beam immediately after the trace reaches the end of the screen. The beam
current is off while the horizontal deflection plate control signals are set to
return the beam to the start of the trace and the trigger circuit is waiting for a
trigger.
blind time
Same as dead time.
BNC
Type of coaxial connector commonly used on measuring equipment. The
initials stand for Bayonet Neill–Concelman (the last two names of the
inventors).
CAT I, CAT II, CAT
III, CAT IV
These are "installation category" ratings and indicate the type of hazards a
user of test equipment is exposed to and that the test equipment can
withstand safely. Refer to the IEC 1010 and related standard for more details.
Informally, CAT I means equipment connected to AC power, but where the
user is isolated by e.g. a transformer. CAT II can mean environments like on
an engineer's bench. CAT III can mean the voltages found inside a building's
circuit breaker panel. CAT IV can mean connections to primary incoming
power from the power company's equipment. The differences in ratings come
from the types and severity of voltage and current transients the user can be
exposed to from the circuit being worked on. For example, a user working in a
CAT IV environment might be exposed to transients of many kilovolts and
kiloamperes (due to lightning strikes or inductive spikes from power interrupts)
.
Test equipment needs to be able to protect the user from the effects of these
transients. F
or example, you'll find sophisticated and expensive fuses in digital
multimeters to contain the dangerous plasma that can result from a multi-
kiloampere transient, thus protecting the user from shocks and burns.
channel
One of the vertical amplifiers on an oscilloscope used to display one trace.
chopped sweep
In analog oscilloscopes, a method of generating a dual-trace display at lower
sweep speeds. One trace is drawn for a fraction of the screen, then the other
trace is drawn for another short fraction. You can see the chopping by
decreasing the time base setting.
CMRR
Common mode rejection ratio, a measure of the ability of a differential
amplifier to ignore a signal common to both inputs.
compensation
In the context of an oscilloscope probe, it's the adjustment of a small variable
capacitor so that the scope has no overshoot or undershoot when looking at
fast rise time edges (e.g., square waves). This is a critical adjustment to be
made for each probe, as it also ensures that correct voltage measurements
can be made with the probe, especially at higher frequencies.
component test
A feature on the B&K 2125A scope that allows a user to display a voltage
versus current waveform for a component. It is capable of identifying and
testing capacitors, inductors, resistors, and semiconductors.
coupling
In the use of an oscilloscope, this describes the electrical coupling between
the input signal and the scope's circuit. It is typically used in context with the
vertical amplifiers and the trigger circuit. See AC coupling and DC coupling.
cross talk
Sometimes referred to as channel isolation or channel separation. The
undesired effect that a signal present on one channel has on another channel.
Less crosstalk means that the channels are better electrically isolated from
one another. Usually expressed in dB.
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