u4091bm-r ATMEL Corporation, u4091bm-r Datasheet - Page 19

• Manufacturer Part Number: u4091bm-r
• Description: Programmable Telephone Audio Processor
• Manufacturer: ATMEL Corporation

12.4
4872A–CORD–08/05
Term Definitions
Table 12-1.
Note:
LOGT > CLOGR
LOGT < CLOGR
LOGR < CLOGT
LOGR > CLOGT
BNMT detects speech
BNMT detects noise
BNMR detects speech
BNMR detects noise
1. Transmit means the transmit attenuator is fully on, and the receive attenuator is at max-
2. Receive means the receive attenuator is fully on, and the transmit attenuator is at max-
3. In idle mode, the transmit and receive attenuator are at half of their maximum
4. Switching to full transmit or receive modes from the idle mode is done at a fast rate
imum attenuation.
imum attenuation.
attenuation.
– Change mode means both the transmit and receive speech are present in
– Idle means speech has ceased in both transmit and receive paths. The attenuators
(30 ms).
approximately equal levels. The attenuators are quickly switched (30 ms) to the
opposite mode until one speech level dominates the other.
are then slowly switched (1.5s) to idle mode.
X = don’t care; Y = I3 and I4 are not both noise.
I1
R
R
R
R
T
T
T
T
Mode Decision for Signal Sensing
I1 = T
I1 = R
I2 = T
I2 = R
I3 = S
I3 = N
I4 = S
I4 = N
I2
R
R
R
R
T
T
T
T
Input
I3
S
Y
Y
X
N
N
N
X
I4
X
Y
Y
S
X
N
N
N
U4091BM-R
Output
Mode
Transmit
Change mode
Change mode
Receive
Idle
Idle
Idle
Idle
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