Appendix C

Definition of Terms
Part 2 - GLOSSARY

AMPERE
An ampere (current) is a (coulomb /second).

BANDWIDTH
Difference in frequency between the upper and lower 3dB down response frequencies.

BI-PHASE
Found as a power feed to most U.S. homes. Derived from a center tapped transformer, it contains two hot phases 180^o with a center tap neutral return. Normally supplied as two 120 volt single phases with 240 volts available across both phases. The neutral return is usually earth grounded.

CAPACITANCE
Measured at 1.0kHz unless otherwise stated.

CLAMP
To clip. To hold turn-on votage as current is increased. Turn-on voltage is the same, or nearly the same, as "on" voltage drop.

CLAMPING RATIO
The ratio of votage drop at a given current to the turn-on voltage.

CLAMPING SPEED Measured with full lead length using a 1kV/ns waeform in a 50 Ohm system, with >/=300MHz or larger bandwidth.

COMBINER
The summation of multiple transmitters into one transmission line. The peak voltage from each signal will be additive and will be higher than the sum of the power would indictate.

COMMON-MODE
Pertaining to signals or signal components referenced to ground.

COULOMB
Measurernent of charge. Often used to indicate the amount ot transferred charge through a gas tube to determine gas tube life. "Q" abbreviation. A coulomb is (current x time).

CROWBAR
To turn-on and clamp close to ground level. Having a high turn-on trigger voltage and a low "on" voltage.

DIFFERENTIAL MODE
Referenced only between conductors (not referenced to ground).

DIPLEXER
(TV Broadcasting). The combining of two transmitters into one transmission line. TV visual and aural.

DUPLEXER
Simultaneous receive and transmit on one transmission line. Where a T connector splits/combines the signals to two groups of filters. The receiver filter passes the receive frequency while rejecting (band stop) the transmitter's frequency. The transmitter filter passes its frequency while attenuating the Class C transmit noise at the receive frequency.

EMI/RFI
Electro Magnetic Interference/Radio Frequency Interference. Broad spectrum noise or interfering signals.

EMP
Electro Magnetic Pulse, usually referred to as the man-made generation by detonation of a nuclear bomb at a high altitude, which generates a very fast pulse (RF) which can be captured by antennas and long unshielded lines. Sometimes referred to as NEMP, HEMP, etc. Lightning can also generate an EMP near the event. Referred to as LEMP.

EMP RATED
Rated as having a fast enough turn-on time or filtering to protect against the effects of an EMP event.

FARADAY SHIELD
An electrostatic (F field) shield made up of a conductive or partially conductive material or grid. A Faraday cage or screen room is effective for protecting inside equipment from outside radiated RF energies.

FILTERING (EMI/RFI)
Measured in a 50 Ohm system - loaded. As per MIL-STD-220.

FREQUENCY RANGE The bandwidth over which both the listed maximum VSWR and Insertion Loss specifications are valid.

GROUND IMPEDANCE
The ground resistance and the inductance/capacitance value of the grounding system. Also called dynamic surge ground impedance.

GROUND LOOP
An undesired potential EMI condition formed when two or more peces of equipment are interconnected and earthed for shack safety hazard prevention purposes.

GROUND RESISTANCE
The resistance value of a given ground rod or grounding system as measured usually by a fall of potential (3 stake) metnod using a 100Hz signal source.

HF
Hign Frequency - normally from 3 to 30MHz however in this catalog it covers from 1.5 to 30Mmz.

HOUSED USE ONLY
For indoor use, or must be further enclosed or rain-proofed for outdoor usage.

IMPEDANCE
Nominal impedance of the devce. The variation of this impedance with frequency is measured as VSWR.

IN-LINE
Power or signal passage through unit. In series with line. Usually a multi-stage protector. Best protection method.

INSERTION LOSS
Loss of a device across the static frequency range. This type of loss is due to the insertion of the unit in series with a signal path.

JOULES
A unit of energy. One joule for one second is equal to one watt of power. Joules is current x time x voltage.

LEAKAGE CURRENT
Usually measured at 50 or 60Hz with 120, 240 or 480 volts dc. However, it can be ac or dc at a specific vatage and frequency.

LOOP RESISTANCE
Total resistance as measured across the input witn the output shorted.

MAXIMUM PEAK LET-THROUGH VOLTAGE
Measured at a given surge current using a given waveform, and using 300MHz bandwidth across a 50 Ohm impedance. (Note: this 50 Ohm impedance may be dc blocked [large bandwidth compared to the surge frequencies present] and 50 Ohm resistive load [termination]).

MAXIMUM POWER
Maximum Continuous Wave (CW) transmit power, without unit degradation.

MAXIMUM SURGE
The maximum single surge current and specified waveform that can be handled by a device without failure during the conduction of that waveform and which ends the life of the device for conducting successive waveforms, but does not allow any generation of outward projectiles.

MULTI-STRIKE CAPABILITY
In most applications current sharing will occur, and in a direct strike event the unit will survive to work again.

POWER
Power is (voltage x current) or a (coulomb/second).

RECEIVER MULTICOUPLER Sometimes with an amplifier, this device has one antenna line and multiple outlets.

RF
Radio Frequencies any and all frequencies that can be radiated as an electromagnetic wave (plane wave).

SAFETY GROUND
The local earth ground. The earth ground which grounds the neutral return. The wire may be green or bare and can be through a metal conduit. It may be earth grounded as many times as needed. (Neutral must only be grounded once at the entry location).

SHF
Super High Frequency - from 3000MHz to 300Hz.

SHUNT PROTECTOR
Line-to-ground. No power or signal passage through unit. Not in-series with line.

SINGLE PHASE A true single phase supply. Usually a two-wire system with one hot phase and a neutral return. A safety earth ground is also present.

SKIN EFFECT The gradient conduction and propagation of RF or RF components of a surge on the outer surfaces of conductors.

TEMPERATURE
The extremes of operating or storage that the unit or unit parts have been tested to under MIL-STD-202 for thermal shock.

THREE PHASE
It consists of sinusoids 120^o apart on at least three wires (Delta) and often four wires (Wye). The fourth wire is a grounded neutral return. In a Delta system there is no reference to ground and thus it is more susceptible to lightning problems.

THROUGHPUT ENERGY
The total energy that will be let through the device using the indicated surge waveform.

TOTAL SURGE ENERGY
Total sum of surge energy for all lines of a protector unit. Measured in joules. The minimum total energy which results in the failure of the unit.

TRANSFER IMPEDANCE
Referring to coax, is the impedance to transfer into or outside the coax at various frequencies usually below 1 MHz. Due to loss of skin effect attenuation or shielding at these low frequencies, coax can be susceptible to interference and noise as well as the radiation of such signals.

TURN-ON TIME - GAS TUBE
The amount of time that exists in the period that occurs when the ramp voltage barely exceeds the turn-on voltage of the device, and the point at which 50% of the peak voltage is achieved during the turn-on (crowbar) process. Measured in a 50 Ohm system with 300MHz bandwidth.

TURN-ON Vac
The maximum ac sine wave voltage that can be passed with the peaks just at the turn-on Vdc level.

TURN-ON Vdc
Turn-on voltage at 1 mA dc with a ramp of 100V/ms typical.

UHF
Ultra-High Frequency - normally from 300 to 3000MHz, however in this catalog we breakout 800 to 1000MHz separately even though it is within this category.

VHF
Very High Frequency - from 30 to 300MHz.

VLF
Very Low Frequency - from 300Hz to 3kHz.

VOLT
A volt is a (joule coulomb).

VSWR
Voltage Standing Wave Rotio (VSWR) of the device across the statec frequency range. VSWR is the amount of reflected signal due to an mpedance mismatch.

VT MAX
The max peak voltage of all combined waveforms. V_total is used for multi-coupled or combined transmit signals.

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