CDB6420 Cirrus Logic Inc, CDB6420 Datasheet - Page 47

• Manufacturer Part Number: CDB6420
• Description: Development Kit
• Manufacturer: Cirrus Logic Inc

Specifications of CDB6420

• Silicon Manufacturer: Cirrus Logic
• Application Sub Type: Speakerphone
• Kit Application Type: Audio / Video / TV
• Silicon Core Number: CS6420
• Kit Contents: Board
• Kit Features: Analog And Digital Patch Area
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

RSThd - Receive Suppression speech-detection
Threshold
5 dB:
3 dB:
6 dB:
NCC - Network (echo canceller) Coefficient
Control
Normal:
Clear:
Freeze:
NErle - Network ERLE threshold
24 dB:
18 dB:
30 dB:
NFNse - Network Full-duplex Noise threshold
zero:
-42 dB:
-54 dB:
TVol - Transmit Volume
30 dB, 27 dB, ... , -57 dB, -60 dB, mute:
RHDet - Receive Half-duplex Detect threshold
5 dB:
3 dB:
6 dB:
HHold - Half-duplex Hold on howl
checked:
unchecked: after howl, CS6420 readapts
DS205DB1
default
make disengaging receive suppression easier
(sensitive to bursty far end noise)
make receive suppression harder to disengage
(less sensitive to far end noise).
coefficients adapt to echo path
coefficients held to zero (no cancellation)
coefficients held to current values and adapta-
tion halted
default
network echo canceller tends to go to full-du-
plex more easily (faster)
network echo canceller requires good perfor-
mance to go to full-duplex (slower)
use NErle as sole criterion to transition to full-
duplex.
echo path may not exist, so go to full-duplex
when noise level is below -42 dB (easy) and in-
ternal determination of path/no path is complete
echo path may not exist, so go to full-duplex
when noise level is below -54 dB (hard) and in-
ternal determination of path/no path is complete
digital volume control, positive numbers are
AGC’d.
default
half-duplex detects far end speech more easily
(more sensitive to far end noise)
half-duplex less sensitive to far end speech (less
sensitive to far end noise)
after howl, CS6420 remains in half-duplex
HDly - Half-duplex holdover Delay
200 ms:
100 ms:
150 ms:
HD - Half-duplex Disable
checked:
unchecked: CS6420 can be in half-duplex as needed.
NseRmp - Noise estimator Ramp rate
1 sec:
0.5 sec:
2 sec:
THDet - Transmit Half-duplex Detect
threshold
5 dB:
3 dB:
6 dB:
RVol - Receive Volume
30 dB, 27 dB, ... , -57 dB, -60 dB, mute:
ACC - Acoustic (echo canceller) Coefficient
Control
Normal:
Clear:
Freeze:
AErle - Acoustic ERLE threshold
24 dB:
18 dB:
30 dB:
default
very easy to break in, but may falsely switch
somewhat easy to break in, but may falsely
switch
CS6420 will never be in half-duplex.
noise estimator increases noise level by
3 dB/ 1 sec
estimated noise level increases by 3 dB/ 0.5 sec
(improves tracking of dynamic noise levels)
estimated noise level increases by 3 dB/ 2 sec
(improves detection of long bursts of speech)
default
half-duplex tends to detect transmit speech
more easily (more sensitive to near end noise)
half-duplex is less sensitive to transmit speech
(less sensitive to near end noise)
digital volume control where positive numbers
are AGC’d
coefficients adapt to echo path
coefficients held to zero (no cancellation)
coefficients held to current values and adapta-
tion halted
default
acoustic echo canceller tends to go to full-du-
plex more easily (faster)
acoustic echo canceller requires good perfor-
mance to go to full-duplex (slower)
CDB6420
47