Lab.gruppen PLM series Operation Manual

Also see for PLM 10000Q: Supplementary guide User manual addendum Specifications Quick start Technical data

Contents

Lab.gruppen PLM series Operation Manual Manual pdf 83 page image

Appendix77PLM Series Operation Manual rev 1.1.99.5 Glossary of Terms, Acronyms and AbbreviationsThe explanations given in Table 9-4 below are based on the specific use of each term in this manual. Thedefinitions are not intended to be exhaustive and many of these terms have wider meanings.Term Description100/1000 Base-T 100/1000 Base-T is IT industry-speak for different standards of Ethernet network. This term incorporates 100 Base-TX, which operatesat 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) andconfigure themselves appropriately. This is termed auto-sensing.Auto-Uplink The Ethernet ports can operate with either straight or crossed network cables. This ability to connect correctly with either type istermed auto-uplinking.Auxiliary Output Some of the configurations possible in the Lake processing system Modules result in a single audio processing channel being created inaddition 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 bothaudio channels and Ethernet networks.Cat-5e/Cat-6, etc. Designations of industry-standard cables suitable for Ethernet networks using four twisted pairs of conductors. Often referred to as UTPcable (Unscreened Twisted Pair). Cat-5 has generally been replaced by Cat-5e (e = ‘enhanced’). Either Cat-5e or Cat-6 cable are suitablefor 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 anexample 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 occurwhen interconnecting two pieces of digital audio equipment if their internal master clocks are not synchronized. Various techniques maybe employed to ensure that this is the case.CPL Relevant only to PLM Series devices. Short for Current Peak Limiter, a Lab.gruppen protection technique which ensures that theamplifier’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 conventionalIT networks to connect two PCs together without using a hub or switch. The auto-uplink feature of the Ethernet ports allows crossedcables 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 controldata to be transmitted via standard IT-industry networks using TCP/IP data packets. The Lake processing system integrated within thePLM 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 tooptimize 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 impedancematching 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 theSecondary ports. Although more complex to implement, the advantage of using a dual-network system is one of greatly improvedreliability as one complete network remains operational if the other should fail.Electronic Balancing See Balancing. In the analog domain, balanced inputs and outputs may be provided on audio equipment either by the use of transformers(traditional, very good, but heavy and expensive) or via electronic balancing circuits (nearly as good, without full electrical isolation, but agreat deal cheaper).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 LakeController 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 isdetected that otherwise seriously affects the performance. Some fault conditions may result in one or all of the channels being muted.Fingerprint Relevant only to PLM Series devices. The Lake Controller comes includes a LoadLibrary consisting of data describing the electricalcharacteristics of commonly-used loudspeakers. The file for each speaker type is termed its Fingerprint.Finite Impulse Response(filter)An alternative design of crossover filter realisable in the digital domain, providing linear phase characteristics. FIR filtering is provided inall Lake devices.FloatingAn analog balanced input or output is said to be floating when full electrical isolation exists between that input or output and theequipment connected to it. Transformer-coupled inputs and outputs are inherently floating. Electronically balanced inputs and outputscan never be truly floating, though better designs – such as that found in the PLM - do mimic the characteristics of transformer-coupleddesigns 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.