QSC - Rave Digital Router guide 电路图.pdf

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1、1 Table of Contents RAVE Digital Audio Router Application Guide Routing: Getting audio from here to there and there, and there to over there .3 One problem, three solutions. 3 The RAVE models and how they work .6 Glossary.7 How it works . 7 Network design. 9 Hardware and medium considerations. 9 Net

2、work topology examples.10 Two nodes with a direct cable connection .10 Two nodes with a 100baseTX hub .10 Star topology .11 Distributed star topology.11 Longer distance through fiber.12 Network limitations.13 And the exceptions to the rules .16 Sample applications.16 Stadium.16 Airport terminal .18

3、Convention center.19 Broadcast facility upgrade .22 RAVE peripherals .23 QSC FE hubs .23 Latency and audio.24 Sound in free space.25 Synchronization with video .25 Specifications .26 Appendix.27 Address high likelihood of errors Reliability: Highly prone to ground loops and EMI Ease of use: Difficul

4、t Routing: Individual channels Expandability: Not advisable Distance: Depends on conditions; a practical limit might be a couple hundred feet, although longer distances are possible with suitable precautions CROSSPOINT ROUTER Complexity: Reasonable Wiring material cost: Moderate to high Wiring labor

5、 cost: Moderate to high Reliability: Susceptible to EMI; may be prone to ground loops; unlikely to have redundant capabilities Ease of use: Good Routing: Usually by individual or pairs of channels Expandability: Possible, depending on the capacity of the router Distance: Depends on conditions; a pra

6、ctical limit might be a couple hundred feet RAVE DIGITAL AUDIO ROUTER Complexity: Very simple Wiring material cost: Very low; might even already be installed Wiring labor cost: Very low Reliability: Free of ground loops; highly immune to EMI; capable of redundant operation Ease of use: Good Routing:

7、 Blocks of 8 audio channels Expandability: Easy; up to 64 transmitted audio channels, but can accommodate any number of receiving devices Distance: With CAT5 UTP cable, up to 100 meters (328 feet) between hub and RAVE unit; with 100baseFX optical fiber, up to 2 kilometers (1.24 miles) under certain

8、conditions 6 The RAVE models and how they work There are currently six RAVE models, and each one handles 16 audio channels. Three have analog inputs, outputs, or both, and the other three are digital, using the AES3 (also known as AES/EBU) format. The AES3 digital inputs and outputs are dual channel

9、 or stereo. The models are: RAVE 88Four digital (AES3) inputs + four digital (AES3) outputs RAVE 81Eight digital (AES3) inputs RAVE 80Eight digital (AES3) outputs RAVE 188Eight analog inputs + eight analog outputs RAVE 16016 analog outputs RAVE 16116 analog inputs The main functional differences amo

10、ng the models lie in the different I/O sections, as these block diagrams show. Analog units have internal jumpers for setting operating levels; details are in the RAVE User Manual. RAVE units use detachable power cords, and their internal power supplies will automati- cally adapt to any AC line volt

11、age from 90 to 240 volts. Internal block diagram of a RAVE unit; chief difference among the different models is the audio I/O (below) Each RAVE unit has an RJ-45 jack on its rear panel for connecting 100baseTX Category 5 (CAT5) network cable. Audio inputs and/or outputs are also on the rear panel, a

12、s is an RS232 port for transmitting serial data over the RAVE network from one RAVE unit to another. A pair of BNC jacks provide a sync output and a “slave” input. More details on the “slave” feature follow later in this book. You can use RAVE units in any combination that is useful to you. If you n

13、eed to take 16 analog signals in one location and send them elsewhere to digital inputs on a tape recorder, for example, you only need to make sure you have the appro- priate RAVE modelsin this case, a RAVE 161 and a RAVE 80to do the job. RAVE 80: 8 AES3 outsRAVE 81: 8 AES3 insRAVE 88: 4 AES3 ins +

14、4 AES3 outs RAVE 160: 16 analog outsRAVE 161: 16 analog insRAVE 188: 8 analog ins + 8 analog outs 7 GLOSSARY Below are some terms used in this manual that might not be familiar to all RAVE users. AES3A technological specification for inter-device conveyance of a dual-channel (stereo) digital audio s

15、ignal. Also called AES/EBU. Crossover cableA type of twisted-pair Ethernet patch cable, but somewhat analogous in function to a null modem cable. Unlike a normal patch cable, however, the transmit and receive wire pairs are swapped at one end, permitting a direct connection of two nodes without a hu

16、b in between. A crossover cable is also suitable for cascading hubs that dont have an available uplink port. It also has nothing to do with an audio crossover. Network channelA RAVE network group of eight audio channels, with a channel number designated by a switch on the sending unit. Dont confuse

17、this term with actual audio channels. A RAVE network multiplexes eight audio channels onto a single network channel and routes the entire network channel as a whole. A receiving RAVE unit set to a particular network channel will output all eight of the network channels audio signals. Uplink portA sp

18、ecial port on a hub, used for cascading to another hub. Usually its offered in tandem with a normal port so you can use one or the other, but not both. For example, a 5-port hub with an uplink allows you to connect to five nodes via the normal ports, or to four nodes via normal ports plus one hub vi

19、a the uplink port. HOW IT WORKS Ethernet networks are most often used for computer systems; a typical application would be in an office with servers, workstations, and shared printers. These devices use the Ethernet medium in an unregulated, non- deterministic way. This means that they transmit data

20、 messages (called “packets”) only when necessary, and the length of the messages may vary depending on the sending device and on the type and amount of data being sent. Each device, or node, on the network that has a message to send waits until there is no traffic, then sends it. If two or more node

21、s try to send messages at the same time, a collision occurs; each node then waits a random length of time before trying again. In this type of application, reasonable latency (the length of time from when the transmitting node has a message ready to send, to when the receiving node actually receives

22、 it) is not a problem, since a second or two delay in the transmission of a print job or an e-mail message wont have any noticeable effect. Audio signals (especially multi-channel), however, generally cant tolerate a delay of even a significant fraction of a second, or even worse, a varying, unpredi

23、ctable delay. This would cause glitches, dropouts, noise, and other nasty and undesirable artifacts in the final audio signal. Therefore, the CobraNet technology used in a RAVE system employs a regulated, deterministic system of packet timing to ensure consistent and reliable transmission without dr

24、opouts or glitches. The RAVE devices on a common network will automatically negotiate the time slots among themselves; one unit will act as the “conductor” and broadcast a clock signal over the network to synchronize all the other RAVE units. For efficiency, the sample data from eight audio channels

25、 are grouped together in each packet. 8 In a typical Ethernet environment, nodes usually send data packets to other specific nodes, and the data packet headers contain both the source address and the destination address. On a RAVE network, however, the sending units broadcast their data packets, wit

26、hout destination addresses but with addresses identifying the network channels the sending units are set to. Then, to receive a particular block of eight audio channels sent by another unit, you would set the receiving unit to the same network channel that the transmitting unit is on, somewhat like

27、tuning a radio or television receiver to a particular frequency or channel. Redundant operation To slave one RAVE unit to another, connect a BNC jumper cable from the sync output of the main unit to the slave input of the redundant unit. Select the same network channel(s) on the slave unit as are se

28、lected on the main unit. As long as the slave input detects the clock signal from the main RAVE unit, it will remain in a sort of “standby” mode, i.e., if it has analog audio outputs, the output relays will stay open to prevent the production of audio signals; if it has digital audio outputs, the bi

29、tstream will continue, but the audio information will be as if the audio channels were muted; if it has analog or digital audio inputs, the unit will not transmit data on the network. However, once the clock signal disappears, as would happen if the main unit detects an internal fault, loses its net

30、work connection, or just fails, the slave unit will go into normal operation. If the clock signal reappears, the slave unit will go back to its standby role. Hub RAVE161RAVE161 RAVE161RAVE161 Main unit Spare unit (set to same network channel as the main unit) Sync out Slave inCAT5 UTP cable BNC-BNC

31、coax cable RJ-45 RJ-45 The spare unit will not transmit data on the network as long as it receives a sync signal from the main unit. If the main unit malfunctions or loses its network connection, its sync signal will stop, it will stop transmitting data, and the spare unit will take over operation.

32、8 audio ins 8 audio ins 8 audio ins 8 audio ins RAVE160RAVE160 RAVE160RAVE160 Hub Main unit Spare unit (set to same network channel as the main unit) Sync out Slave in CAT5 UTP cable BNC-BNC coax cable 8 audio outs 8 audio outs 8 audio outs 8 audio outs RJ-45 RJ-45 The spare units audio outputs will

33、 stay muted as long as it receives a sync signal from the main unit. If the main unit malfunctions or loses its network connection, its sync signal will stop, its outputs will mute, and the spare units audio outputs will activate. An example of a redundant input setupAn example of a redundant output

34、 setup When you operate a pair of RAVE units with analog inputs (RAVE models 161 and 188) in a redundant configuration, you can safely “Y” the pairs of inputs between the main unit and the slave unit as you would with any parallel analog devices with high input impedances. The internal output relays

35、 in analog RAVE units allow you to also parallel or “Y” the individual output channels of the RAVE units with their particular backup channels. The relays will open when the RAVE unit is in standby or inoperative, preventing active outputs from trying to drive the inactive outputs. With digital unit

36、s, you can often safely “Y” the AES3 inputs if the units are located physically close to each other and the actual Y cables are reasonably short. For even better reliability, however, use a digital distribution amplifier instead of Y cables. Do not “Y” digital AES3 outputs. 9 Network design Because

37、a RAVE network uses a 100baseTX Fast Ethernet medium, you would generally use the same approach to designing the RAVE network as you would for a computer network. There are several ways to configure a RAVE network, from very simple to relatively complex. The number of RAVE units in the network, wher

38、e they are located, and your future expansion plans will determine what net topology would be best. The same techniques you would use in designing a conventional 100-Mbps Fast Ethernet will assist you in designing a RAVE network. HARDWARE AND MEDIUM CONSIDERATIONS RAVE units can use unshielded twisted pair wiring, but it must be at least Category 5 quality. Anything less may cause unreliable operation of the network, if it runs at all. Fortunately, most new Ethernet cable installations in b