ClearOne comm AP800 EchoCancellationSetup, EC Reference bus, A B C D, ECRef#, G-Link, Master Unit

	EchoCancellationSetup	A	B	C	D	1	2	3	4	5	6	7	8	ECRef
26	1						Outputs							G-Link
								Installation ~ LCD Programming
	ECRef#2
	DefineG-LinkECRefBus
	Figure 2.19. Echo Cancellation Setup Default Matrix

EC Reference bus

This bus provides a system-wide echo canceller reference signal. When multiple AP800 units are linked together and will be using only one output channel to drive the loudspeaker system, that output must be defined as the sample reference which will be used by all of the linked AP800s for echo cancellation. It allows the reference signal to be passed to additional G-Linked mic channels and their associated echo cancellers. For echo cancellation to function properly, the output which the master unit will use as the EC reference must be identified to the slave units via the G-Link (see Figures 2.36 & 2.37 for routing configuration).

The following example illustrates the echo cancellation setup necessary to

EchoCancellationSetup		A B C D		1 2		3	4	5	6 7 8	ECRef
	comm nicate the EC reference from the master unit to the slave unit:
	Master Unit
	“D fine EC Ref #1” tells the master unit which output (in this case, output D) will
1	be used as the reference for echo cancellation for the master unit. This output (D)
ECRef#2	must also	be defined	as the “G	-Link	EC	Ref	bus”	which	slave units will refer to
DefineG-LinkECRefBus	wh n you	are defining	their EC	referencesOutputs(see Figure					2.20).	G-Link

Figure 2.20. EC Setup for Multiple Units to One Output (Master Unit)

Slave Unit

Because the slave unit will not be using one of its own outputs as the EC reference, “EC Ref #1” must be defined as the “G-Link EC Ref” only (as shown in Figure 2.21). The slave unit will then use the master’s defined output (in this case, output D) as its reference for echo cancellation.

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