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SigNET PRO Range Instructions
Approved Document No. DAU0000105 Rev 2
PHASED ARRAY HEARING LOOP SYSTEMS (MODEL DEPENDENT)
Increasingly to ensure uniformity of the magnetic field, especially in larger installations where
large amounts of metal are present and to limit overspill, phased array loop systems are being
specified. A phased array system works by producing two AFILS signals 90° out of phase with
each other. These signals are connected to two identical hearing loops laid in a special
overlapping pattern. The resultant magnetic field is evenly spread within the covered area but
falls off quickly outside the loop.
Note:
The smallest practical room width for a phased array loop is 5m.
The SigNET PRO Range amplifiers offer:
1. A true ‘all-in-one’ professional phased-array AFILS solution.
2. An onboard overspill reduction phase shifter and metal compensation control.
3. An internal PSU.
See diagram below for a typical dual loop design. Note the sizes shown are examples only as
each system must be uniquely designed. For further advice on phase shifted loop design please
contact SigNET technical department.
2m
3.2m
1.6m offset
Green Loop
(Array 1)
Red Loop
(Array 2)
2m
3.2m
Baseline
PRO Dual
Loop Amplier
Note 1:
If high metal content is present, the amplifier’s area of coverage will be reduced, and
further reduced, as the
Metal Comp
control is increased.
Note 2:
If the
Peak
indicator lights strongly, reduce the
Line
Input
level and then adjust the
Metal Comp
control buttons. You may have to adjust both these controls several times to
achieve the most favourable operation.
Note 3:
Metal compensation tests must be carried out to comply with the requirements of
BS EN 60118-4.
Loop Drive 1 & Loop Drive 2 Drive (Model Dependent)
These menu displays are used to adjust the strength of the magnetic field generated by
induction loops 1 & 2 by increasing the output current being driven into the loops. To comply
with BS EN 60118-4, Output (field strength) should be set up using a FPROK1 test kit.
Select either
Loop 1 Drive
or
Loop 2 Drive
display and press the
Up
4
and
Down
control
buttons to adjust the current out for each loop.
The
Peak
indicator, when illuminated (shown below), indicates that the amplifier is delivering
its maximum design current. Intermittent Peak indications are acceptable, but if the Peak
indicator is mostly on, consider installing a more powerful Pro Range amplifier.
VU
Loop 1 Drive
Metal Comp
Loop 2 Drive
Down
Up
min
max
Phantom Phase
Limit
Fault 1 2
HOT!
Peak
VU
Loop 2 Drive
Loop 1 Drive
Phase Shift
Down
Up
min
max
Phantom Phase
Limit
Fault 1 2
HOT!
Peak
Brightness
This function will increase or decrease the brightness of the menu display. It is recommended
that brightness level is not set to its maximum setting for a long period of time.
8 of 16
SigNET PRO Range Instructions
Approved Document No. DAU0000105 Rev 2
Phase Shift (Model Dependent)
This menu display is used to apply optional phase shift between the two hearing loops.
By default, the amplifier will have phase shift turned off.
Select the
Phase Shift
display and press the
On
4
and
Off
control buttons to toggle phase
shift on and off between loop 1 and loop 2, as shown below.
VU
Phase Shift
Loop 2 Drive
Brightness
Off
On
min
max
Phantom Phase
Limit Peak
Fault 1 2
HOT!
VU
Phase Shift
Loop 2 Drive
Brightness
Off
On
min
max
Phantom Phase
Limit Peak
Fault 1 2
HOT!
