—In this paper, we present a novel 128-point FFT/IFFT processor for ultrawideband (UWB) systems. The proposed pipelined FFT architecture, called mixed-radix multipath delay feedback (MRMDF), can provide a higher throughput rate by using the multidata-path scheme. Furthermore, the hardware costs of memory and complex multipliers in MRMDF are only 38.9% and… (More)
Index Terms—80211n, fast Fourier transform (FFT), multiple input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM).
—An all-digital phase-locked loop (ADPLL) for high-speed clock generation is presented in this brief. The proposed ADPLL architecture uses both a digital control mechanism and a ring oscillator and, hence, can be implemented with standard cells. The ADPLL implemented in a 0.3-m one-poly-four-metal CMOS process can operate from 45 to 510 MHz and achieve… (More)
—This work presents a portable digitally controlled oscillator (DCO) by using two-input NOR gates as a digitally controlled varactor (DCV) in fine-tuning delay cell design. This novel varactor uses the gate capacitance difference of NOR gates under different digital control inputs to establish a DCV. Thus proposed DCO can improve delay resolution 256 times… (More)
—This work presents a clock generator with cascaded dynamic frequency counting (DFC) loops for wide multiplication range applications. The DFC loop, which uses variable time period to estimate and tune the frequency of the digitally controlled oscil-lator (DCO), enhances the resolution of frequency detection. The conventional phase-frequency detector (PFD)… (More)
—In this paper, a 64-state four-bit soft-decision Viterbi decoder with power saving mechanism for high speed wireless local area network applications is presented. Based on path merging and prediction techniques, a survivor memory unit with hierarchical memory design is proposed to reduce memory access operations. It is found that more than 70% memory… (More)
—The differential power analysis (DPA) has become a big threat to crypto chips since it can efficiently disclose the secret key without much effort. Several methods have been proposed in literatures to resist the DPA attack, but they largely increase the hardware cost and severely degrade the throughput. In this brief, a security problem based on ring… (More)
—An LDPC decoder chip fully compliant to IEEE 802.16e applications is presented. Since the parity check matrix can be decomposed into sub-matrices which are either a zero-matrix or a cyclic shifted matrix, a phase-overlapping message passing scheme is applied to update messages immediately , leading to enhance decoding throughput. With only one… (More)