Glossary Of Terms, Acronyms And Abbreviations - Lab.gruppen PLM series Operation Manual

9.5

Glossary of Terms, Acronyms and Abbreviations

The explanations given in Table 9-4 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 is IT industry-speak for different standards of Ethernet network. This term incorporates 100 Base-TX, which operates
100/1000 Base-T
at 100 Mbps, and 1000 Base-T which operates at 1000 Mbps (1 Gbps).
Access Point
See Wireless Access Point.
The Ethernet ports automatically determine the base speed of the network they are connected to (10 Base-T or 100 Base-T) and
Auto-Sensing
configure themselves appropriately. This is termed auto-sensing.
The Ethernet ports can operate with either straight or crossed network cables. This ability to connect correctly with either type is
Auto-Uplink
termed auto-uplinking.
Some of the configurations possible in the Lake processing system Modules result in a single audio processing channel being created in
Auxiliary Output
addition to a crossover. This is termed an Auxiliary output.
Large Ethernet networks are often implemented with a very high speed "trunk" part of the network topology feeding main switches,
Backbone
which in turn support smaller, lower-speed local networks. The term backbone is used to describe such a trunk.
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
Bandwidth
audio channels and Ethernet networks.
Designations of industry-standard cables suitable for Ethernet networks using four twisted pairs of conductors. Often referred to as UTP
Cat-5e/Cat-6, etc.
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 Cat-5 has generally been replaced by Cat-5e (e = 'enhanced').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.
An Ethernet network comprising several devices interconnected using the Secondary connectors to daisy-chain the units together is an
Chain
example of a network with a chain topology.
Digital audio is produced by sampling analog audio at a known, fixed rate, controlled by some form of master clock. Problems can occur
Clock
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.
Relevant only to PLM Series devices. Short for Current Peak Limiter, a Lab.gruppen protection technique which ensures that the
CPL
amplifier's output transistors can never attempt to deliver more than their rated current.
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
Crossed Network Cable
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.
A new-generation audio data protocol developed by Audinate
Dante
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 is effectively a 'fine' gain adjustment performed in the digital domain, which can be applied to digital input signals to
Digital Gain Offset
optimize the signal to the gain structure.
A distribution amplifier (usually abbreviated to DA) is an audio buffer stage – usually with zero gain – with one input and several outputs.
Distribution Amplifier
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.
A network topology consisting of two (usually) identical networks, one connecting to the Primary Ethernet ports and the other to the
Dual-Network Topology
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.
See Balancing. In the analog domain, balanced inputs and outputs may be provided on audio equipment either by the use of transformers
Electronic Balancing
(traditional, very good, but heavy and expensive) or via electronic balancing circuits (nearly as good, without full electrical isolation, but a
great deal cheaper).
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
Event Log
Controller software called the Event Log.
A Fault in the device occurs when one of the operating parameters exceeds pre-determined safety levels, or when a condition is
Fault
detected that otherwise seriously affects the performance. Some fault conditions may result in one or all of the channels being muted.
Relevant only to PLM Series devices. The Lake Controller comes includes a LoadLibrary consisting of data describing the electrical
Fingerprint
characteristics of commonly-used loudspeakers. The file for each speaker type is termed its Fingerprint.
Finite Impulse Response
An alternative design of crossover filter realisable in the digital domain, providing linear phase characteristics. FIR filtering is provided in
all Lake devices.
(filter)
An analog balanced input or output is said to be floating when full electrical isolation exists between that input or output and the
equipment connected to it. Transformer-coupled inputs and outputs are inherently floating. Electronically balanced inputs and outputs
Floating
can never be truly floating, though better designs – such as that found in the PLM - do mimic the characteristics of transformer-coupled
designs to a high degree.
Frame
Lake terminology for a physical unit containing a Lake processing system, i.e. a single LM 26, PLM or legacy Lake Processor.
Pty Ltd, allowing multichannel high-resolution digital audio plus control
®
PLM Series Operation Manual rev 1.1.9
Appendix
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