2.3
RF Transmitter
2.3.1
IQ Modulator
The transmitter features a direct IQ modulator to minimise frequency drift during a transmit timeslot, which results
in a controlled modulation index. Digital baseband transmit circuitry provides the required spectral shaping.
2.3.2
Power Amplifier
The internal PA output power is software controlled and configured through a PS Key. The internal PA on the
CSR8640 BGA has a maximum output power that enables it to operate as a Class 1, Class 2 and Class 3
Bluetooth radio without requiring an external RF PA.
2.4
Bluetooth Radio Synthesiser
The Bluetooth radio synthesiser is fully integrated onto the die with no requirement for an external VCO screening
can, varactor tuning diodes, LC resonators or loop filter. The synthesiser is guaranteed to lock in sufficient time
across the guaranteed temperature range to meet the Bluetooth v3.0 specification.
2.5
Baseband
2.5.1
Burst Mode Controller
During transmission the BMC constructs a packet from header information previously loaded into memory-mapped
registers by the software and payload data/voice taken from the appropriate ring buffer in the RAM. During reception,
the BMC stores the packet header in memory-mapped registers and the payload data in the appropriate ring buffer
in RAM. This architecture minimises the intervention required by the processor during transmission and reception.
2.5.2
Physical Layer Hardware Engine
Dedicated logic performs:
■
Forward error correction
■
Header error control
■
Cyclic redundancy check
■
Encryption
■
Data whitening
■
Access code correlation
■
Audio transcoding
Firmware performs the following voice data translations and operations:
■
A-law/µ-law/linear voice data (from host)
■
A-law/µ-law/CVSD (over the air)
■
Voice interpolation for lost packets
■
Rate mismatch correction
The hardware supports all optional and mandatory features of the Bluetooth v3.0 specification including AFH and
eSCO.
Advance Information
This material is subject to CSR's non-disclosure agreement
© Cambridge Silicon Radio Limited 2011
Page 24 of 110
CS-209182-DSP1
CSR8640 BGA
Data Sheet
