LFSR Characteristic Polynomials for Pseudo-Exhaustive TPG with Low Number of Seeds

A fully scanned digital circuit can be tested pseudo-exhaustively by first introducing a number of extra bypass storage cells to limit the test-phase input dependency of each test-phase output and then using a Linear Feedback Shift Register (LFSR) to feed the chain of the original scan cells and the extra cells. For the design of the LFSR, the goal is to minimize the pseudo-exhaustive test length with low hardware overhead. If the LFSR uses a primitive characteristic polynomial then it requires only one seed, but the candidate primitive polynomials may all fail to satisfy the target test length. In this paper, we present a methodology that enlarges the list of candidate polynomials, if the prescribed number of seeds is more than one. Experimental results show that the new candidate polynomials are often instrumental in satisfying the given test length and seed restriction.     

微波电路的仿真和设计

仿真软件越来越广泛地应用于微波电路设计中。介绍了微波电路与系统仿真软件Serenade8.5的功能和应用,并以微波低通滤波器的仿直和设计为例说明了它的使用。以巴特沃斯原型滤波器为基础,首先分析了它的特性,然后对其进行优化,得到满足设计目标的低通滤波器。     

Comparative performance of some polynomial-based lowpass filters for microwave/digital transmission applications

This paper reports on the comparative performances of some polynomial based lowpass filters in the lumped elements, microstrip and defected ground structure (DGS) environment. The microwave designers are normally familiar with Butterworth, Chebyshev and Bessel filters. However, many more polynomials based, ripple and non-ripple types LPF have been suggested for the low-frequency applications. Some of these LPF, such as L-opt, H-type, Transitional Butterworth-Legendre (TBL), Pascal, Legendre group of LPF, are compared for their applications in analog microwaves, digital transmission, efficiency enhancement of the linear power amplifiers and five level partial response modulations. A method is reported to compute the ripple frequency for the Legendre group of LPF and Pascal LPF. Further, a design is suggested to significantly improve group delay performance of high selectivity filters.     

应用于WLAN系统具有高线性度的基带Gm-C滤波器

本文介绍了一种应用于无线局域网(WLAN)收发机系统的跨导-电容(Gm-C)低通滤波器,该滤波器能够工作于低电压并具有高线性度。该射频发射器(Tx)中的滤波器采用截止频率为9.8MHz的三阶切比雪夫低通滤波器原形,在30MHz频率处的阻带衰减达到35dB。由于采用了工作在线性区MOS的伪差分跨导,此滤波器的IIP3可达9.5dBm之高。本电路采用0.35-μm CMOS工艺实现,滤波器的芯片面积为0.41mm0.17mm,工作在3.3V电源电压时所消耗电流为3.36mA 。