Lab.gruppen PLM 20000Q - Manual (Page 88)

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Appendix
PLM Series Operation Manual rev 1.2.3
9.5 Glossary of Terms, Acronyms and Abbreviations
The explanations given in Table 9-5 below are based on the specific use of each term in this manual. The
definitions are not intended to be exhaustive and many of these terms have wider meanings.
Term Description
100/1000 Base-T 100/1000 Base-T is IT industry-speak for different standards of Ethernet network. This term incorporates 100 Base-TX, which operates
at 100 Mbps, and 1000 Base-T which operates at 1000 Mbps (1 Gbps).
Access Point See Wireless Access Point.
Auto-Sensing
The Ethernet ports automatically determine the base speed of the network they are connected to (10 Base-T or 100 Base-T) and
configure themselves appropriately. This is termed auto-sensing.
Auto-Uplink
The Ethernet ports can operate with either straight or crossed network cables; the ability to connect correctly with either type is termed
auto-uplinking.
Auxiliary Output
Some of the configurations possible in the Lake processing system Modules result in a single audio processing channel being created in
addition to a crossover. This is termed an Auxiliary output.
Backbone
Large Ethernet networks are often implemented with a very high speed “trunk” part of the network topology feeding main switches,
which in turn support smaller, lower-speed local networks. The term backbone is used to describe such a trunk.
Bandwidth
The bandwidth of a signal channel or interconnection is the range of frequencies it is able to handle. The term can be applied to both
audio channels and Ethernet networks.
BEL
Available on PLM 20000Q devices only, the Breaker Emulation Limiter (BEL) provides functionality to emulate a breaker, with user
adjustable characteristics.
Breaker A breaker (in relation to BEL configuration) is a virtual fuse providing three breaker emulation settings (Conservative, Fast & Universal).
Cat-5e/Cat-6, etc.
Designations of industry-standard cables suitable for Ethernet networks using four twisted pairs of conductors. Often referred to as UTP
cable (Unscreened Twisted Pair). Cat-5 has generally been replaced by Cat-5e (e = ‘enhanced’). Either Cat-5e or Cat-6 cable are suitable
for networking Lake and Lab.gruppen devices.
Chain
An Ethernet network comprising several devices interconnected using the Secondary connectors to daisy-chain the units together is an
example of a network with a chain topology.
Clock
Digital audio is produced by sampling analog audio at a known, fixed rate, controlled by some form of master clock. Problems can occur
when interconnecting two pieces of digital audio equipment if their internal master clocks are not synchronized. Various techniques may
be employed to ensure that this is the case.
CPL An abbreviation for Current Peak Limiter, a Lab.gruppen protection technique which ensures that the amplifier’s output transistors can
never attempt to deliver more than their rated current.
Crossed Network Cable
An Ethernet cable in which four of the eight conductors (pins 1, 2, 5 & 6) are not wired pin-to-pin. Such a cable is required in conventional
IT networks to connect two PCs together without using a hub or switch. The auto-uplink feature of the Ethernet ports allows crossed
cables to be used if wished. See also Straight network cable.
Dante
A new-generation audio data protocol developed by Audinate ® Pty Ltd, allowing multichannel high-resolution digital audio plus control
data to be transmitted via standard IT-industry networks using TCP/IP data packets. The Lake processing system integrated within the
PLM includes a dual-redundant Dante network interface, providing digital audio inputs and outputs via Ethernet.
dBu dBu’s are usually used instead of voltages to describe signal levels in audio systems. A signal level of 0 dBu may be taken as 0,775 Vrms.
Delay Up to two seconds of delay may be added to the input and/or output channels to time-align loudspeaker arrays.
Digital Gain Offset
Digital gain offset is effectively a ‘fine’ gain adjustment performed in the digital domain, which can be applied to digital input signals to
optimize the signal to the gain structure.
Distribution Amplifier
A distribution amplifier (usually abbreviated to DA) is an audio buffer stage – usually with zero gain – with one input and several outputs.
Mono, stereo and AES3 digital versions can be obtained. Use of a DA to feed a signal to several destinations ensures correct impedance
matching and isolation between source and destinations.
Dual-Network Topology
A network topology consisting of two (usually) identical networks, one connecting to the Primary Ethernet ports and the other to the
Secondary ports. Although more complex to implement, the advantage of using a dual-network system is one of greatly improved
reliability as one complete network remains operational if the other should fail.
Dynamic Function
Buttons
The eight buttons around the front panel display are termed dynamic function buttons because their function varies depending upon
which display page is currently on-screen.
Electronic Balancing
In the analog domain, balanced inputs and outputs may be provided on audio equipment either by the use of transformers or via
electronic balancing circuits.
Event Log
The details of any fault or warning conditions which arise in the device during operation are recorded in a data file created by the Lake
Controller software called the Event Log.
Fault
A Fault in the device occurs when one of the operating parameters exceeds pre-determined safety levels, or when a condition is
detected that otherwise seriously affects the performance. Some fault conditions may result in one or all of the channels being muted.
Fingerprint
The Lake Controller comes includes a LoadLibrary consisting of data describing the electrical characteristics of commonly-used
loudspeakers. The file for each speaker type is termed its Fingerprint.
FIR Filter
Finite Impuse Response Filter. An alternative design of crossover filter realisable in the digital domain, providing linear phase
characteristics. FIR filtering is provided in all Lake devices.