paging lesson 2 Flashcards
70v output amplifiers are used _________
primarily for paging systems
Constant voltage systems use how many wires and what are they for?
2 wire
audio power is supplied from the centralized amplifier
the raw 24v DC power needed by a self amplified system can be carried in a ___________since it carries no interfering signals
telecom cable
a self amplified system audio signal is the same as you would find on any _________
analog telephone
how many wires does a self amplified system require and what are they for?
2 pairs of wires
one pair for audio and one pair for 24v DC power
what are speaker taps for?
select peak power that the speaker will consume
lower current =___________
less voltage drop
a slc provides a simple and cost effective way to remotely control volume of a network of up to______ speakers
150
reducing the current flow in a wire by a factor of ____ will reduce the power loss by a factor of ______
2
4
direct output amplifiers are used with _____________
low impedance speakers
microphone cable is always _____
shielded
low signal levels prevent _______
crosstalk
25, 16, and 8 ohm amplifiers are used __________
for strict building code requirements
do not run 70v system cables with__________
analog phone lines
limit AUX input cables to ________ feet. longer cables equal ___________
6 feet
more noise
step down audio transformers are located_______
on the speaker and tapped at various levels
bufex
local volume controls for a group of speakers
when sending power signals over long distances it is important to minimize the amount of _________ in the wire
current
Aux inputs have a ___________ signal
unbalanced
what are 2 ways to acomplish paging
- 25v or 70v centralized amplifiers with passive speaker
- self amplified speakers operating with a 24v power supply
reducing the current in a wire will reduce _________
power loss
SLC
signal level control
what is the formula used to determine the amount of current flow in the speaker wires?
I = √(P/R)
a slc provides a simple and cost effective way to remotely control ________ of a network of up to 150 speakers
volume
how many cables does a microphone have ___________. what are they?
3
2 for a balanced signal and 1 for ground/shield
why use a 70v outputs
low current allows long runs
MIC inputs have a _______ signal
balanced
what feature allows emergency announcements to be heard at higher levels than the volume setting on the volume control?
bypass
