LG RBFS B921A User Manual

Description of Functional BlocksDescription of Functional Blocks

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436-7991

RBFSRBFS--B921A BT B921A BT Ass’yAss’y ModuleModule

Rev A, Nov 2009Rev A, Nov 2009

RBFS-B921A-AN-01-A

LG Innotek

Hanyang Univ. 1271, Sa-dong, Sangrok-gu ,

Ansan-si, Gyeonggi-do 426-791, Korea

Tel:[phone]

-31-

www.lginnotek.com

COMMERCIAL IN CONFIDENCE

Copyright ⓒ 2007, LG Innotek Co., Ltd. http:\\www.lginnotek.com

All specification are preliminary and LG Innotek reserves the right to change these without notice.

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1. RF Receiver Block

1.1 Receiver Path

The receiver path uses a low IF scheme to down-convert the received bit signal for
demodulation in the digital demodulator and bit synchronizer. The receiver path
provides a high degree of linearity, an extended dynamic range, and high order on­chip channel filtering to ensure reliable operation in the noisy 2.4 GHz ISM band. The

­in most applications with no off-chip filtering. For integrated handset operation where
the Bluetooth function is integrated close to the cellular transmitter, minimal external
filtering is required to eliminate the desensitization of the receiver by the cellular
transmit signal.

1.1.1 Digital Demodulator and Bit synchronizer

The digital demodulator and bit synchronizer takes the low IF received signal and
performs an optimal frequency tracking and bit synchronization algorithm.

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1.1.2 Receiver Signal Strength Indicator

The BCM2046 radio provides an Receiver Signal Strength (RSSI) signal to the
baseband so that the controller can take part in a Bluetooth power-controlled link by
providing a metric of its own receiver signal strength to determine whether the
transmitter should increase or decrease its output power.

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2. RF Transmitter Block

2.1 T ransmitter Path

The BCM2046 features a fully integrated zero IF transmitter. The baseband transmit
data is digitally GFSK modulated in the modem block and up-converted to the 2.4 GHz
ISM band in the transmitter path. The transmitter path consists of signal filtering, I/Q
up-conversion, high-output power amplifier (PA), and RF filtering. It also incorporates
new modulation schemes P/4-DQPSK for 2 Mbps and 8-DPSK for 3 Mbps to support
enhanced data rate.

2.1.1 Digital Modulator

The digital modulator performs the data modulation and filtering required for the GFSK,
π/4DQPSK, and 8-DPSK signal. The fully digital modulator minimizes any frequency
drift or anomalies in the modulation characteristics of the transmitted signal and is
much more stable than direct VCO modulation schemes.

2.1.2 Digital Demodulator and Bit Synchronizer

The digital demodulator and bit synchronizer takes the low IF received signal and
performs an optimal frequency tracking and bit synchronization algorithm.

2.1.3 Power Amplifier

The integrated PA for the BCM2046 can transmit at a maximum power of +4dBm for
class2 operation. The transmit power levels are for basic rate and EDR. Due to the
linear nature of the PA, combined with some integrated filtering, no external filters are
required for meeting Bluetooth and regulatory harmonic and spurious requirements.
For integrated mobile handset applications, where Bluetooth is integrated next to the
cellular radio, minimal external filtering can be applied to achieve near thermal noise
levels for spurious and radiated noise emissions.

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