Operation Instruction Manua
l
1ZPR
Microphone Pre-amp
Features
The 1ZPR has compressor, noise gate, equalisation
controls and optional chime (one to three note).
The unit is fully monitored and complies with BS5839 part4.
Simple operation by the use of a single button Speak bar.
The unit is supplied mounted on a double gang wall plate.
The 1ZPR has be designed for use with electret or high
impedance (>1K) dynamic microphones.
5 volt phantom voltage is available to power electret
microphones.
Technical Description
Microphone signals are passed to a voltage controlled
amplifier under control of a signal derived from rectifying
the stage output signals, providing 3:1 compression ratio.
The output of this stage is fed to an LED output level
display and a three-band equaliser (100 Hz, 1KHz, 10 kHz).
Power is supplied at nominal 24 VDC via separate cabling,
the phantom power on the audio + and audio - being used
for fault detection only. A regulator circuit provides 15 VDC
for powering the 1ZPR electronics.
Front Panel Features
The 1ZPR provides for the following LED indications
:
Name
Function / Description
1
OK
GREEN when no fault detected.
2
FAULT
AMBER when fault detected.
3
SPEAK
GREEN when system ready for paging announcement, FLASHING GREEN when system is
busy.
4
VU
VU meter to show audio level. VU meter is constantly active and will light in sync with audio
peaks to indicate that the audio path to the input stage is intact. This occurs even when speak
bar is not pressed.
Block Diagram
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DocNo.DCP0001372 ADS 14/11/05 rev4
