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Definitions

Aliasing:

The sampling of a magnitude VS time whose interval makes a false repetition, and an inability to analyze data at that interval.

 

Antenna:

A device used to radiate or receiving radio waves.

 

ASICs:

Application Specific Integrated Circuit.

 

Bandwidth:

The start and stop frequency delta.

 

Capacitance:

The ratio of the charge on one of the conductors of a capacitor to the potential difference between the conductors.

 

Clock frequency:

The master frequency of the periodic pulses that schedule the operation of a computer.

 

Common mode:

The same amplitude and phase at both inputs of a balanced transmission line. The energy imparted to ground when a balanced transmission line is not ideal.

 

Cross Talk: The measured unwanted coupling from one channel and another.

 

Current: The net transfer of electric charge per unit time. The rate of flow across a surface per unit time.

 

Cutoff Frequency:

is the place where the wavelength is able to fit once in the transmission line.

 

DC:

Electric current that flows in one direction only.

 

AC:

Electric current that reverses direction periodically, many times per second.

 

dB:

The ratio of 2 magnitudes. Also the ratio of a power to reference power.

 

Electrical length:

Unit of time required to travel in a transmission line.

 

EMC:

Unwanted coupling that occurs between circuits.

 

EMI:

Interference at high frequencies causing unwanted disturbance to other systems.

 

Energy:

Measured in milliwatts. Differences expressed in dB.

 

EYE Pattern:

A specific plot denoting skew, Tr, skin effect, jitter, cross talk, insertion loss, resistance, common mode, simultaneously. (Other masks besides EYE are also common)

 

Frequency:

The number of cycles completed by a periodic quantity in a unit time.

 

Field lines:

A topological arrangement of electric and magnetic fields.

 

Gain: The increase in signal power.

 

Gating: To selectively pre-select a window of the magnitude VS time interval for close inspection used in a Fourier series to remove unwanted disturbances.

 

Ground: Electrical connection to a reference conducting plane. Provide a return path in a transmission system.

 

Group Delay:

The measured envelope of time VS frequency of a transmission line.

 

Impedance:

The AC characteristics of real and imaginary components.

 

Impedance matching:

Where the transmission line and the source are going to have minimum reflections and minimum distortions.

 

Inductance:

The ratio of the electromotive force to the rate of change of the current.

 

Insertion Delay:

The measured time it takes for a signal to pass completely through a transmission line usually referenced to the 50% points.

 

Insertion Loss:

The loss in power received at the load due to the transmission line.

 

Launch:

The transfer point where energy transfers from one point to another.

 

Loss Tangent:

Energy lost in the dielectric partially due to the slower propagation compared to air.

 

Magnetic waves:

perpendicular to the electric wave.

 

Mismatch:

The impedance of the source does not match the impedance of the transmission line.

 

Reflection:

A discontinuity caused by a wave traveling back into the source.

 

Resistance(DC):

The opposition that a material offers to the flow of direct current, equal to the voltage drop across the material divided by the current through the material.

 

Resistance(AC):

the real part of the complex impedance.

 

Resonance:

The frequency at which there is a sharp peak of power when a circuit contains inductance, capacitance, and resistance of specific values.

 

Return Loss:

The ratio between the incident power upon a discontinuity and the power reflected from the discontinuity.

 

Ringing:

A cyclic arrangement of alternating transients that are under damped but decreasing over time in amplitude and period.

 

Rise Time:

The transition time (usually 10% to 90%) when a signal is suddenly applied from a well-behaved source to a transmission line.

 

Shielding:

A conductive barrier.

 

Shielding effectiveness:

How much energy can be radiated.

 

Sine waves:

A wave whose amplitude varies as the sine of a linear function of time.

 

Skew:

The delta in time of the signal traveling through more than one transmission line.

 

Skin effect:

The layer of the center conductor at which all the current is carried at a specific frequency.

 

Spectrum:

The distribution of energy distributed over frequency.

 

SWR:

The ratio of maximum amplitude to the minimum amplitude of a wave in a transmission line. (Standing Wave Ratio.)

 

TEM:

Transverse electric, magnetic. Particular waves are propagated. Electric waves; transverse.

 

TDR:

Time Delay Reflectometry.

 

TDT:

Time Delay Through.

 

Transition:

An engineered launch for least disturbance of energy.

 

Transmission:

The transfer of a signal from one location to another.

 

Transmission Line:

A system by which signals can be transferred between 2 or more points.

 

Velocity of propagation:

The speed at which a signal passes through a transmission line with respect to air.

 

Voltage:

Potential difference. Electromotive force. The difference in electric potential between 2 dissimilar nodes connected by a conductor.

 

Wavelength:

The distance between 2 points having the same phase in 2 consecutive cycles in a periodic wave along a line in the direction of propagation.

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