STLC2500A View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'STLC2500A' PDF : 37 Pages View PDF
Functional description
STLC2500A
5.5.1
V1.2 detailed functionality - Extended SCO
● User Perspective - Extended SCO
This function gives improved voice quality since it enables the possibility to retransmit lost or
corrupted voice packets in both directions.
● Technical perspective - Extended SCO
eSCO incorporates CRC, negotiable data rate, negotiable retransmission window and multi-
slot packets. Retransmission of lost or corrupted packets during the retransmission window
guarantees on-time delivery.
Figure 3. eSCO
SCO
SCO
SCO
SCO
ACL
ACL
SCO
SCO
t
eSCO retransmission window
5.5.2
V1.2 detailed functionality - Adaptive Frequency Hopping
● User Perspective - Adaptive Frequency Hopping
In the Bluetooth spec 1.1, the Bluetooth devices hop in the 2.4 GHz band over 79-channels.
As WLAN 802.11 has become popular, there are improvements in the Bluetooth spec 1.2
specifying how Bluetooth units can avoid jammed bands and provide an improved co-
existence with WLAN.
● Technical perspective - Adaptive Frequency Hopping
Figure 4. AFH
f
AFH(79)
WLAN used frequency
t
f
AFH(19<N<79)
WLAN used frequency
t
First the Master and/or the Slaves identify the jammed channels. The Master decides on the
channel distribution and informs the involved slaves. The Master and the Slaves, at a
predefined instant, switch to the new channel distribution scheme.
No longer jammed channels are re-inserted into the channel distribution scheme. AFH uses
the same hop frequency for transmission as for reception.
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