A hardware efficient 64-QAM low-IF transceiver baseband for broadband communications

This paper presents a hardware efficient VLSI design of digital baseband for 64-QAM communication systems over the last-mile cable network. This VLSI system design involves a cost-efficient architecture of the adaptive equalizer and a two-phase linear architecture of the pulse shaping filters, which reduce the hardware requirement by a factor of four comparing with traditional quadrature direct form FIR filters. In this design, the two-fold carrier recovery loop possesses a pull-in range of ±100kHz (i.e. ±18, 500ppm of the symbol rate) and -82dBc jitter suppression. Based on the proposed multi-staged LMS-based fractionally-spaced equalizer, the receiver realizes the symbol spaced timing recovery in a ±200ppm tolerance of the symbol rate. The acquisition time of the proposed 64-QAM blind adaptive system is 7ms, and the transceiver reaches the operation speed of the case for 32.28Mb/s 64-QAM low-IF digital CATV system over NTSC 6MHz bandwidth channels. Using 0.35 μm CMOS technology, the transceiver design occupies a chip area 5.5mm × 5.5mm and power consumption 1.35W (1.0W for RX) when the power supply is 3.3V.