资 源 简 介
The BCM3345 combines an advanced QAM receiver; anadvanced QAM transmitter; a complete DOCSIS/EuroDOCSISMedia Access Controller (MAC); a 140-MHz MIPS32communicaTIon processor; a 16-bit, 100-MHz SDRAMinterface; 10/100 Ethernet MAC with integrated transceiver andMII interface; and a USB 1.1 controller with integratedtransceiver.The QAM receiver directly samples a tuner output with a 10-bitA/D converter and input ACG amplifier. The receiver digitallyresamples and demodulates the signal with recovered clock andcarrier TIming, filters and equalizes the data, and passes softdecisions to an ITU-T J.83 Annex A/B/C compaTIble decoder. A40-tap adapTIve decision feedback equalizer is implemented.The receiver supports variable symbol rate 64/256 QAM FECdecoding. The final received data stream is delivered in a serialMPEG-2 transport format. All gain, clock, and carrier,acquisition and tracking loops are integrated in the QAMreceiver.The upstream transmitter takes burst or continuous data, providesFEC encoding and pre-equalization for DOCSIS/EuroDOCSISapplications, filters and applies QPSK or QAM16 modulation tothe data stream, amplifies the signal through the integratedupstream power amplifier, and provides a direct 0–65 MHzanalog output.
