The role of
the SQ45 within an SM30 public address system
Within the Philips SM40 public address system, the SQ40/45
power amplifiers feed the loudspeakers located in geographical
and/or functional zones where people must be reached with
background music, announcements, pre-recorded messages and
alarm signals.
The SQ40/45 'music' input with adjustable pre-set volume
control was ideally suited for distributing one out of several
continuous background music sources.The 'priority call' input
with a fixed input level is used for occasional paging and
other calls. An in-built relay switches the amplifier from
the 'music' input to the 'priority call' input. Such functions
are controlled by the Philips SM40 Control Centre (see parts
list).
An additional feature included in all SQ45 range of amplifiers
is a balanced 'Test Input' facility, used for injecting a
20kHz 'pilot-tone' to monitor the amplifiers performance.
If used in combination with the SM40 microprocessor controlled
surveillance system (see parts
list) all amplifiers, loudspeaker cabling and
speakers will be constantly monitored.
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