The marker on a trace that can be repositioned either by front panel controls or by programming commands
Active Trace
A trace that is being swept (updated) with incoming signal information.
Annotation
The labeling of specific information on the display (such as frequency or power).
Aperture
The frequency span of the network analyzer used for calculating group delay. The narrower the aperture, the finer the resolution of the group delay variations, but noise is reduced by increasing the aperture.
Array
A set of numbers or characters that represents any given function.
Attenuator
An RF or microwave device used to reduce the power level of a signal by precise, incremental amounts over its entire frequency range.
AUX
Auxiliary; refers to rear-panel input connector.
Averaging
A noise reduction technique that computes each data point based on consecutive sweeps and weighted by a user-specified averaging factor. Each new sweep is averaged into the trace until the total number of sweeps is equal to the averaging factor.
The difference between the frequencies of a continuous frequency band within which performance of a device falls within specifications.
Binary
A method of representing numbers in a scale of two (on or off, high-level or low-level, one or zero). A compact, fast format used to transfer information to and from the analyzer.
Broadband Device
A device that operates over a very wide frequency range and exhibits only small variations in response over that range.
BW
Bandwidth
A set of instructions that are translated into instrument actions. The actions are usually made up of individual steps that together can execute an operation.
Controller
A device capable of specifying the talker and listeners for an information transfer. An external computer connected to an instrument to control its operation.
Decibel: a relative unit of measure. The ratio in dB is given by: 10 log10 (P1/P2) where P1 and P2 are the measured powers. The dB is preferred instead of arithmetic ratios or percentages because when components are connected in series, their effect on power, expressed in dB, may be arithmetically added and subtracted. For example, if a 3dB attenuator is connected to a 10dB amplifier, the net gain of the two components is (-3dB + 10dB = +7dB).
dBc
dB relative to the carrier power
dBc/Hz
dB relative to the carrier power per Hertz of bandwidth
dBm
Absolute unit of measure in decibels: 0dBm = 1 mW. The conventions of the dB (adding and subtracting) continue to apply.
Default
A known set of conditions used in the absence of user-defined conditions.
Dimension
To specify the size of an array. The number of array rows or columns.
Display Formats
Graphical formats for displaying measurement data. These include single channel, overlay (multiple traces on one graticule), split (each trace on separate graticules).
Drift
The slow change in signal frequency.
DUT
Device Under Test
Dynamic Range
In a receiver, the range of signal levels, from minimum to maximum, that can be reliably measured simultaneously. Dynamic range allows small signals to be measured in the presence of large signals. Source power and receiver compression usually limits the maximum boundary to dynamic range. Receiver residual responses and noise floor usually limit the minimum power boundary.
Electro-Magnetic Interference: Unintentional interfering signals generated within or external to electronic equipment. Typical sources could be power-line transients, noise from switching-type power supplies and/or spurious radiation from oscillators. EMI is suppressed with power-line filtering, shielding, etc.
Enter
The process of inputting information.
EPROM
Electronically Programmable, Read-Only Memory
Error Message
A message on a display that indicates an error condition. Missing or failed hardware, improper user operation, or other conditions that require additional attention can cause an error condition. Generally, the requested action or operation cannot be completed until the condition is resolved.
ESD
Electro Static Discharge
Ethernet
A network that adheres to the IEEE 802.3 Local Area Network standard.
Frequency Modulation
Frequency
The number of periodic oscillations, vibrations, or waves per unit of time, usually expressed in cycles per second, or Hertz (Hz).
Frequency Range
The range of frequencies over which a device or instrument performance is specified.
Frequency Resolution
The ability of a network analyzer to measure device characteristics at closely spaced frequencies and display them separately. Resolution of equal amplitude responses is determined by IF bandwidth. Resolution of unequal amplitude responses is determined by IF bandwidth and bandwidth selectivity.
Front Panel Key
Keys that are located on the front panel of an instrument. The key labels identify the function the key activities. Numeric keys and step keys are two examples of front panel keys.
Function
The action or purpose that a specific item is intended to perform or serve. The network analyzer contains functions that can be executed via front panel key selections, or through programming commands.
Gigahertz
Giga
Prefix for one billion.
GPIB
General Purpose Interface Bus - IEEE 488 bus is interconnect bus and protocol, allows linking of instruments and computer.
Paper copy of data.
Hardkey
A front-panel key, which engages a single analyzer function or presents a single menu of softkeys.
Host Name
A unique name that is used to identify each host machine on a network. The host name is directly linked to, and can usually be used in place of, the IP address. The user or the system administrator usually creates the host name.
HTTP
HyperText Transfer Protocol: Used to carry World Wide Web (WWW) traffic.
Input/Output
IF
Intermediate Frequency: the frequency at which a signal is processed after mixing.
Impedance
The ratio of voltage to current at a port of a circuit, expressed in ohms.
Input Attenuator
An attenuator between the input connector and the first mixer of a spectrum analyzer (also called an RF attenuator). The input attenuator is used to adjust the signal level incident to the first mixer, and to prevent gain compression due to high-level or broadband signals. It is also used to set the dynamic range by controlling the degree of internally-generated distortion. For some analyzers, changing the input attenuator settings changes the vertical position of the signal on the display, which then changes the reference level accordingly. In Agilent microprocessor-controlled analyzers, the IF gain is changed to compensate for changes in input attenuator settings. Because of this, the signals remain stationary on the display, and the reference level is not changed.
Insertion Loss
The difference between the power measured before and after the insertion of a device. The attenuation between the input and output of a device.
Interface
A connection that allows a common communication link between two or more instruments.
Interpolate
To determine a value of a signal between to adjacent points by a procedure or algorithm.
IP
Internet Protocol
IP Address
Internet protocol address: a unique number that is assigned to each device which is to be connected to a TCP/IP network. Before using an analyzer on a network, your network administrator will need to assign an IP address. An IP address consists of a 32-bit value presented in decimal dot notation: 4 octets (bytes) separated by a dot.
Kilobytes per second
Lines input by the user that overlay the analyzer's measurement data to allow automatic detection of data that is out of the acceptable range. Pass/Fail annotation, audio alarms, or electronic output can be triggered to notify the operator or on-line computer program of the over-limit condition.
Linear Device
A device in which the output is continuously proportional to the input.
LO
Local Oscillator. In a superheterodyne system, the LO is mixed with the received signal to produce a sum or difference equal to the intermediate frequency (IF) of the receiver.
A graphical symbol along a display trace that is annotated with measurement characteristics of that specific data point.
Marker Functions
Mathematical or statistical computation on the data of one or more markers to provide the operator more information. For example, the marker delta function calculates and displays the difference between two markers.
Maximum Input Level
The maximum signal power that may be safely applied to the input of an analyzer. The maximum input level is typically 1 W (+30 dBm) for Agilent spectrum analyzers.
Random variations of unwanted or disturbing energy in a communications system from man-made and natural sources that affects or distorts the information carried by the signal. See also Signal-to-Noise Ratio.
To move or set off a determined amount. Used in instruments for offsetting frequencies, limits, delay, loss, impedance, etc.
A function on an analyzer that searches for the largest response and places a marker on it.
Preset
A pre-defined instrument state (that also runs an analyzer self-test). The action of pushing the Preset key.
Protocol
A set of conventions that specify how information will be formatted and transmitted on a network, and how machines on a network will communicate.
A circuit or system designed for the reception and/or measurement of signals in a specified frequency spectrum.
Remote
A mode of operation where another device (or computer) controls an instrument via the HP-IB. In this mode, the instrument front panel keys are disabled. Front panel operation is called local operation.
Return Loss
The amount of dB that the reflected signal is below the incident signal. If zero signal is reflected, the impedance of the device is equal to the characteristic impedance of the transmission system, and return loss is infinite. If the entire incident signal is reflected, the return loss is zero. See also S-Parameters, Reflection Coefficient, and SWR.
RF
Radio Frequency (from approximately 50 kHz to approximately 3 GHz). Usually referred to whenever a signal is radiated through the air.
The stop frequency minus the start frequency. The span setting determines the horizontal-axis scale of the analyzer display.
Sweep
The ability of the source to provide a specified signal level over a specified frequency range in a specified time period. Also see Sweep Mode and Sweep Type. In data processing mode, a series of consecutive data point measurements, taken over a sequence of stimulus values.
Sweep Mode
The way in which a sweep is initiated or selected, e.g., single, continuous, alternate, or chopped.
Syntax
The grammar rules that specify how commands must be structured for an operating system, programming language, or applications.
The acceptable result levels for any given measurement.
Trace
A series of data points containing frequency and response information. The series of data points is often called an array. The number of traces is specific to the instrument.
Trigger
A signal that causes the instrument to make a measurement. The user can select several options for triggering, such as manual, continuous, or external (for synchronizing measurements to an external source).
Dimensions on the measured quantities. Units usually refer to amplitude quantities because they can be changed. In analyzers with microprocessors, available units are dBm (dB relative to 1 mW dissipated in the nominal input impedance), dBmV (dB relative to 1 mV), dBW (dB relative to 1 1W), V (volts), W (watts).
A symbol, the value of which changes either from one iteration of a program to the next, or within each iteration of a program.