Description of Functional Blocks
RBFS-B921A BT Ass’y Module
Rev A, Nov 2009
LG Innotek
Hanyang Univ. 1271, Sa-dong, Sangrok-gu ,
Ansan-si, Gyeonggi-do 426-791, Korea
Tel:82-31-436-7653
Fax:82-31-436-7991
www.lginnotek.com
RBFS-B921A-AN-01-A |
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.
RBFS-B921A
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 front-end topology, with built-in out-of-band attenuation, enables the device to be used 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.
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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RBFS-B921A
2. RF Transmitter Block
2.1 Transmitter 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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