Procom MI4M - Manual (Page 3)

Data Sheet
MI4M
Microphone Measurement Module
Function Description:
The principle functions are illustrated in the following block diagram.
Satz 1
MI4M
-48V
+0V
S
t
e
u
e
r
u
n
g
KS
+5V
GND
-5V
BUS
P
C
M
Satz 4
Lb
La
- -48V
+
+
-
24V
-24V
-48V
A
D
Lb
La
- -48V
+
+
-
24V
-24V
-48V
I/O
C
o
n
t
r
o
l
Set 1
Set 1
Block diagram MI4M
The pre-boosted noise signals are sent to the MI4M from the microphones
mounted on the station platform over shielded 600 Ohm four-wire cables
(2 wires LF, 2 wires power supply).
The signals are digitized after being prefiltered and adjusted in level. An
adjustment value is calculated for the amplifier level control from the indi-
vidual samples through a multi-phase averaging.
By providing signals over a larger period of time, it can be ensured that
brief level peaks such as e.g. trains travelling through or brake noises do
not lead to exaggerated level adjustments.
The adjustment response curve for the amplifier is specified through the
configuration software ICS.
Date: 26.03.2009 Page: 3/5 Author: HS Document-No.: DB_MI4M_2332_01
© 2008 ProCom, All rights and technical changes reserved