BCM4356XKWBGT Datasheet, PDF (42/195 Pages) Cypress Semiconductor – Single-Chip 5G WiFi IEEE 802.11ac 2×2 MAC/ Baseband/Radio with Integrated Bluetooth 4.1, FM Receiver, and Wireless Charging

BCM4356 Advance Data Sheet
Bluetooth Power Management Unit
Packet Loss Concealment
Packet Loss Concealment (PLC) improves apparent audio quality for systems with marginal link performance.
Bluetooth messages are sent in packets. When a packet is lost, it creates a gap in the received audio bit-stream.
Packet loss can be mitigated in several ways:
• Fill in zeros.
• Ramp down the output audio signal toward zero (this is the method used in current Bluetooth headsets).
• Repeat the last frame (or packet) of the received bit-stream and decode it as usual (frame repeat).
These techniques cause distortion and popping in the audio stream. The BCM4356 uses a proprietary waveform
extension algorithm to provide dramatic improvement in the audio quality. Figure 10 and Figure 11 show audio
waveforms with and without Packet Loss Concealment. Broadcom PLC/BEC algorithms also support wideband
speech.
Figure 10: CVSD Decoder Output Waveform Without PLC
Packet Loss Causes Ramp-down
Figure 11: CVSD Decoder Output Waveform After Applying PLC
Broadcom^®
May 8, 2015 • 4356-DS103-R
BROADCOM CONFIDENTIAL
Page 41