CMOS
MT9122
Dual Voice Echo Canceller
Preliminary Information
with Tone Detection
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
Dual channel 64ms or single channel 128ms
echo cancellation
Conforms to ITU-T G.165 requirements
ITU-T G.165/G.164 disable tone detection
supported on all audio paths
Narrow-band signal detection
Programmable double-talk detection threshold
Non-linear processor with adaptive suppression
threshold and comfort noise insertion
Offset nulling of all PCM channels
Controllerless mode or Controller mode with
serial interface
ST-BUS or variable-rate SSI PCM interfaces
Selectable
µ/A-Law
ITU-T G.711;
µ/A-Law
Sign
Mag; linear 2’s complement
Per channel selectable 12 dB attenuator
Transparent data transfer and mute option
19.2 MHz master clock operation
ISSUE 5
September 1996
Ordering Information
MT9122AP
28 Pin PLCC
MT9122AE
28 Pin PDIP
-40
°C
to + 85
°C
Description
The MT9122 Voice Echo Canceller implements a
cost effective solution for telephony voice-band echo
cancellation
conforming
to
ITU-T
G.165
requirements. The MT9122 architecture contains two
echo cancellers which can be configured to provide
dual channel 64 millisecond echo cancellation or
single channel 128 millisecond echo cancellation.
The MT9122 supports ITU-T G.165 or G.164 tone
disable requirements.
The MT9122 operates in two major modes:
Controller or Controllerless. Controller mode allows
access to an array of features for customizing the
MT9122 operation. Controllerless mode is for
applications where default register settings are
sufficient.
Applications
•
•
Wireless Telephony
Trunk echo cancellers
Sin
Linear/
µ/A-Law
Offset
Null
+
Non-Linear
Processor
-
Adaptive
Filter
Control
Linear/
µ/A-Law
Sout
Disable Tone
Detector
Microprocessor
Interface
Double-Talk
Detector
Disable Tone
Detector
Offset
Null
Linear/
µ/A-Law
Programmable
Bypass
Narrow-Band
Detector
Linear/
µ/A-Law
12dB
Attenuator
Rout
ENA2
ENB2
NLP
REV
LAW
FORMAT
TD1
TD2
Rin
ENA1
ENB1
CONFIG1
CONFIG2
S1/DATA1
S2/DATA2
S3/CS
S4/SCLK
Echo Canceller A
Echo Canceller B
VDD
VSS
PWRDN
IC
F0od
F0i
BCLK/C4i
MCLK
Figure 1 - Functional Block Diagram
8-17
MITEL [ MITEL NETWORKS CORPORATION ]
