CDB6422 Cirrus Logic Inc, CDB6422 Datasheet - Page 12

• Manufacturer Part Number: CDB6422
• Description: Development Kit
• Manufacturer: Cirrus Logic Inc

Specifications of CDB6422

• Silicon Manufacturer: Cirrus Logic
• Application Sub Type: Telephone
• Kit Application Type: Communication & Networking
• Silicon Core Number: CS6422
• Description/function: Audio DSPs
• Operating Supply Voltage: 5 V to 12 V
• Product: Audio Modules
• Kit Contents: Evaluation Board
• Rohs Compliant: No
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: CS6422

3.2.29 ext - EXT Jumper Set
3.2.30 d {number} - Dial Phone Number
3.2.31 ? - List Commands
4. USAGE EXAMPLES
This section provides some examples of configura-
tion and use. All of the following examples assume
+12V operation (PWR_SEL1-4 = '+12V'), external
microphone plugged into 1/8" jack, and CS6422 in-
ternal mic preamp enabled.
4.1
This section contains useful information regarding
the operation of the CS6422 in a system.
1) The CS6422 begins operation in half-duplex
2) If an echo canceller is enabled but no echo path
12
mode.
mode automatically when both of its echo can-
cellers have trained.
exists, then it will never train and the system
will remain in half-duplex. If an echo path does
not exist for the echo canceller, then the EC
should be disabled. For example, if there is no
coupling between NO and NI, the Network
the UART
CS6422 Usage Notes:
is installed, allowing an external source to
configure the CS6422
‘,’ will add a small delay between numbers.
A. Message indicating that the jumper EXT
B. No arguments needed
C. No pushes to the MSG Stack
A. Dials phone numbers up to 14 digits. A
B. No pushes to the MSG Stack
C. Description:
A. Prints the list of available commands to
B. No arguments needed
C. No pushes to the MSG Stack
The device switches to full-duplex
3) If the echo path is distorted (THD > 2%) then
4) If the echo path is weak (gain between AO and
5) The coupling gain must always be less than
6) The Acoustic Echo Canceller trains when there
7) The Network Echo Canceller trains when there
8) During full-duplex operation, if there is speech
9) The echo cancellers will not train in the pres-
4.2
This section describes how to adjust the mic
preamp gain or the speaker/mic position to set the
Echo Canceller should be disabled by setting
NECD to ‘1’.
the performance of the echo canceller will be
degraded, which can cause the device to remain
in half-duplex or to drop to half-duplex fre-
quently (during loud speech, for example).
Common sources of distortion are the speaker,
the speaker driver, and clipping at the A/D con-
verter at APO.
APO less than -30dB) then the echo canceller
will have difficulty adapting to the path and the
system will remain in half-duplex. A good goal
is to have a coupling gain between -20dB and -
6dB
0dB, otherwise a full-scale signal at AO or NO
will cause clipping at the associated A/D at
APO or NI, resulting in large amounts of distor-
tion which degrades echo canceller perfor-
mance.
is speech in the receive path (through RVol) but
not in the transmit path.
is speech in the transmit path (through TVol)
but not in the receive path.
in both transmit and receive paths (double-
talk), then neither echo canceller will train.
ence of any periodic signals (sine waves or mu-
sic, for example). Appropriate training signals
are voice and white noise.
Setting the Acoustic Coupling:
CDB6422
DS295DB2