General Technical Description - AKG CM12/8 Manual

2. General Technical Description

The CM12/8 combines a high quality digitally-controlled analog signal path with a sophisticated
microcontroller to provide flexible, high-performance matrix mixing. Low distortion (.005% THD)
CMOS analog switches are used as the signal crosspoint connectors. These switches also allow an
input to send signal to various outputs at different send levels. A specially designed audio attenu­
ator provides 78dB of output level control in 1dB increments. In addition, individual switches on the
outputs provide for either a microphone or line level signals.
A frequency shaped noise source is provided for use in situations where noise masking might be
needed as one of the setup options. An example is a bench conference in a courtroom, where
noise is output over system loudspeakers in areas remote from the judges' bench in order to keep
the conference from being overheard.
9 nonvolatile memories can be used to store multiple setups, 6 of which can be recalled from
contact closures to rear panel connectors. This allows for basic room combining applications, as
well as accommodating flexible microphone placement in a room. The CM12/8 matrix may be
extended with extra units if more inputs are needed. The Audio Link In and Out connectors allow
simple expansion of the input capability of the system.
An RS-232 port is available to allow many of the functions of the CM12/8 to be controlled either by
a computer or a dedicated control system (such as the AMX or Crestron systems).
PROCESSOR
CONTROLLED
BALANCED
LINE INPUT
CHANNEL
1 OF 12
PROCESSOR
CONTROLLED
NOISE
SOURCE
NOISE
GENERATOR
MIX BUS
SWITCH
ARRAY
1 2 3 4 5 6 7 8
SWITCH
ARRAY
Figure 1 - CM12/8 Block Diagram
SAVE
SELECT
68HC705
uC
DOWN
UP
SERIAL
EEPROM
SERIAL
DATA
BUS
10dB
10dB
10dB
10dB
10dB
10dB
10dB
10dB
PROCESSOR
CONTROLLED
ATTENUATORS
17
CM12/8
LECNET (RS-232) OUT
LECNET (RS-232) IN
MEMORY PRESETS
FRONT PANEL
LCD DISPLAY
AUDIO LINK IN
AUDIO LINK OUT
BALANCED
MIC/LINE
SWITCH MIC/LINE OUTPUT 1
MIC/LINE BALANCED
SWITCH MIC/LINE OUTPUT 2
BALANCED
MIC/LINE
SWITCH MIC/LINE OUTPUT 3
MIC/LINE BALANCED
SWITCH MIC/LINE OUTPUT 4
BALANCED
MIC/LINE
SWITCH MIC/LINE OUTPUT 5
MIC/LINE BALANCED
SWITCH MIC/LINE OUTPUT 6
MIC/LINE BALANCED
SWITCH MIC/LINE OUTPUT 7
MIC/LINE BALANCED
SWITCH MIC/LINE OUTPUT 8