User's Manual

XXXXXXXX Rev X

LA-5127 CF card Integration Guide

Confidential Material – Disclosure Strictly Prohibited.

The 802.11 WLAN MAC protocol is implemented in firmware supporting BSS and

IBSS operation. Low-level protocol functions such as request to send (RTS)/clear

to send (CTS) generation and acknowledgement, fragmentation and de-

fragmentation, and automatic beacon monitoring are handled without host

intervention.

3.1 Transmitter Path

After the Medium Access Controller (MAC) receives the data from the host

computer through CF interface, the MAC appends a preamble and header and

sends the data to the Base-Band Processor (BBP).

The radio supports the legacy and CCK data rates in 2.4GHz and the OFDM

data modulation modes for 2.4GHz band.

The CCK mode transmitter is a Direct Sequence Spread Spectrum (DSSS) PSK

modulator when in CCK mode supporting 5.5Mbps and 11Mbps. It also supports

DBPSK for 1Mbps and DQPSK for 2Mbps. The preamble is always transmitted

as the DBPSK waveform and the header can be configured as DBPSK or

DQPSK while the data packets can be DBPSK, DQPSK, or CCK.

The OFDM transmitter supports BPSK, QPSK, 16QAM or 64QAM modulation.

The OFDM transmitter operates in 2.4GHz band providing 6, 9, 12, 18, 24, 36,

48, and 54Mbps data rates. The OFDM signal is fed to a pair of Digital to Analog

Converters (DACs) to produce the In Phase (I) and the Quadrature (Q) signals.

The TX signals are then amplified by the PA and routed through the diplexer to

the dual band antenna for transmission.

3.2 Receive Path

The received signal from the antenna is fed to the diplexer, which separates the

signal path for the low band (2.4GHz) and the high band (5.2GHz). The signal is

then fed to a filter/balun in the low band and to a balun in the high band path. The

signal then goes to the transceiver chip for direct down conversion for both low

and high bands. The design contains LNAs, Quad Up/Down Converters,

Synthesizers, Low-Pass Filters, and Baseband AGC Receiver Amplifiers.

3.3 Microprocessor Control