LG LDS201 User Manual

Description of Functional Blocks

BM-LDS201

Rev A, Aug 2010

LG Electronics

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

Ansan-si, Gyeonggi-do 426-79 1, Korea

Tel:82-31-436-7653

Fax:82-31-436-7991

www.lge.com

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

1. RF Transmitter Block

1.1 Transmitter Feature

The transmitter part of RF-Receiver is internally based on direct synthesis of the RF frequency. The frequency synthesizer includes a completely on-chip LC VCO and a 90 degrees phase shifter for generating the I / Q LO signals to the down-conversion mixers in receive mode. The baseband transmit data is digitally MSK modulated in the modem block and up-converted to the 2.4 GHz ISM band in the transmitter path. The transmitter path consists of Modulator, I/Q up-conversion through frequency synthesizer, high-output power amplifier (PA). RF-Receiver also uses MSK modulation schemes for 250kbps.

1.1.1 Digital Modulator

It is suited for systems targeting compliance with digital modulation systems as defined by FCC part 15.247. Also, the sync word is a 16 bit con f i g u r a b l e f i e l d ( c a n b e re p e a t e d t o g e t a 3 2 bit) that is automatically inserted at the start of the packet by the modulator in transmit mode.

1.1.2 Digital Demodulator and Symbol Synchronizer and Data Decision

Th e RF-Receiver con t a i n s an a d v an c e d an d highly configurable demodulator. Channel filtering and frequency offset compensation is performed digitally. When using MSK modulation, the demodulator will compensate for the offset between the transmitter and receiver frequency, within certain limits, by estimating the centre of the received data. The bit synchronization algorithm extracts the clock from the incoming symbols.

Byte synchronization is achieved by a continuous sync word search. The demodulator uses this field to find the byte boundaries in the stream of bits.

1.1.3 Power Amplifier

The integrated PA for the RF-Receiver can transmit at a maximum power of +1dBm. In some applications it may be necessary to extend the link range. Adding an external power amplifier is the most effective way of doing this. The power amplifier should be inserted between the antenna and the balun, and two. T/R switches are needed to disconnect the PA in RX mode.

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