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一类可控序列的构造和分析 总被引:1,自引:0,他引:1
本文通过利用GF(2^m)(m≥2)上L级m序列来控制其上的L级m序列的方法,构造出了一类具有较高线性复杂度的周期序列,这类序列的线性复杂度的下界为L(L+1)^m-L^m)。 相似文献
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本文利用有限域GF(p^α)(p>2为素数,α≥1为正整数)上二次特征η建立了GF(p^α)上一类互钟控序列,即LSRg[d0,d1,d2]-互钟控序列。讨论了当用作移位时钟控制的前馈函数g(x1,x2,…xn)为二次型时,LSRg[d0,d1,d2]-互钟控序列的周期和线性复杂度的特点。 相似文献
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产生2元de Bruijn序列的一个新算法 总被引:3,自引:0,他引:3
2元n级deBruijn序列是由n级移位寄存器产生的周期为2n的移位寄存器序列,给出了2元deBruijn序列的一个新的生成算法,该算法能生成2s·g(n,s)个n级如de Bruijin序列,其中,0≤s≤2(n-7)/3;当 2l-1<s≤2L时,g(n,s)=n-3L-6-[(n-2L-6)/(L+1)]。 相似文献
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关于本原M序列的一些自相关函数取值 总被引:7,自引:0,他引:7
本文讨论了由m序列叠加小项x2…xn构成的M序列的自相关性能,获得了c(n+1)=-4或0或4,c(τ1)=-4,c(τ2-1)=0或4(τ1和τ2意义见定理1)的新结果,同时并给出了c(n+k)(k≥2)的可能取值范围。 相似文献
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假设老化是从亚稳态到稳态的变化,利用反应动力学理论对Sol-Gel法制备的CoMnNiMgO热敏元件的老化特性进行了研究,推导出老化公式△R/Ro=Σri[1-exp(-t/τi)]其中:τi=τoiexp(Ei/kT))。结果表明理论与实验能很好地一致,对于本文所研究的热敏元件,符合公式AR/Ro=r1[1-exp(-t/τ1)]+r2[1-exp(-t/τ2)],该式中:,r1=11.767×10-3;r2=20.6735×10-3;τ1=6.4578×10-3exp(6190.89/T);τ2=1.0461×10-6exp(8ll6.24/T)。 相似文献
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对1.3μm和1.55μm波长的Si1-xGex波长信号分离器(WSD)和Si1-xGex/Si应变超晶格(SLS)红外探测器的集成结构进行了系统的分析和优化设计.优化结果为:(1)对Si1-xGexWSD,Ge含量x=0.05.波导的脊高和腐蚀深度分别为3μm和2.6μm.对应于λ1=1.3μm和λ2=1.55μm波长的波导脊宽分别为11μm和8.5μm.(2)对Si1-xGex/SiSLS探测器,Ge含量x=0.5.探测器的厚度为550nm,由23个周期的6nmSi0.5Ge0.5+17nmSi组成. 相似文献
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用LPE研制的室温连续工作的1.48μm单量子阱激光器 总被引:1,自引:0,他引:1
利用液相外延(LPE)技术研制出室温连续工作的InGaAsP/InP分别限制单量子阶(SCH-SQW)双沟平面掩埋(DC-PBH)激光器。室温下,腔面未镀膜的激光器最低阈值电流为23mA(激光器腔长为200μm,CW,13℃)。激射波长为1.48μm,最高输出功率达18.8mW(L=200μm.CW,18℃)。脉冲输出峰值功率大于50mW(脉冲宽度1μs、频率1kHz),未见功率饱和。量子阱的阱宽为20nm[1]. 相似文献
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作者用高气压加纵向非均匀磁场获得了二种单频、自稳频高输出功率的外腔式He-Ne激光器,1m激光器的频率非稳定度为6.175×10 ̄(-9)(τ≤10s)和3.38×10 ̄(-9)(τ≤1s);1.8m激光器的频率非稳定度为1.1×10 ̄(-8)(τ≤1s)和2×10 ̄(-8)(τ≤10s),所有数据由中国计量科学院测定。本文是继文献[1],[8],[9]和[10]发表后,对这两种激光器的自稳频原理的再分析。 相似文献
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本文通过利用GF(2m)(m2)上L级m序列来控制其上的L级m序列的方法,构造出了一类具有较高线性复杂度的周期序列。这类序列的线性复杂度的下界为L((L+1)mLm)。 相似文献
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本文研究了几类线性分组码C[n,k,d]的网格图复杂度s(C)。给出并证明了码长为奇数的两类线性分组码的网格图复杂度。同时得出了有关可纠t个错的本原BCH码[2^m-1,2^m-1-mt]及其扩展本在BCH码的网格图复杂度的若干结论。从而避免了必须先寻找码的直和结构才可得到码的网格图复杂度的较好上界。 相似文献
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Oggier F.E. Sloane N.J.A. Diggavi S.N. Calderbank A.R. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2005,51(12):4320-4325
Two subspaces of a vector space are here called "nonintersecting" if they meet only in the zero vector. Motivated by the design of noncoherent multiple-antenna communications systems, we consider the following question. How many pairwise nonintersecting M/sub t/-dimensional subspaces of an m-dimensional vector space V over a field F can be found, if the generator matrices for the subspaces may contain only symbols from a given finite alphabet A/spl sube/F? The most important case is when F is the field of complex numbers C; then M/sub t/ is the number of antennas. If A=F=GF(q) it is shown that the number of nonintersecting subspaces is at most (q/sup m/-1)/(q/sup Mt/-1), and that this bound can be attained if and only if m is divisible by M/sub t/. Furthermore, these subspaces remain nonintersecting when "lifted" to the complex field. It follows that the finite field case is essentially completely solved. In the case when F=C only the case M/sub t/=2 is considered. It is shown that if A is a PSK-configuration, consisting of the 2/sup r/ complex roots of unity, the number of nonintersecting planes is at least 2/sup r(m-2)/ and at most 2/sup r(m-1)-1/ (the lower bound may in fact be the best that can be achieved). 相似文献
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根据有限域GF(2~m)上的正规基表示和Massey-Omura乘法器,本文提出了一个复杂性为O(logm)的求逆算法。新算法完成一次求逆运算只需要[log22(m-1)]+w(m-1)-1次乘法和m-1次循环移位,这里[x]表示小于等于x的最大整数,w(m-1)表示m-1的二进制表示中“1”的个数。 相似文献
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基于周期为2m-1的二元伪随机序列,利用交织法构造了一类满足一定条件的周期为2m+1-1的基序列集,进而利用这些基序列集构造得到了一类参数达到Tang-Fan-Matsufuji界的二元最佳低相关区序列集。这类低相关区序列集具有更多的序列数目,应用到准同步CDMA系统可以支持更多的用户。 相似文献
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List decoding of q-ary Reed-Muller codes 总被引:2,自引:0,他引:2
Pellikaan R. Xin-Wen Wu 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2004,50(4):679-682
The q-ary Reed-Muller (RM) codes RM/sub q/(u,m) of length n=q/sup m/ are a generalization of Reed-Solomon (RS) codes, which use polynomials in m variables to encode messages through functional encoding. Using an idea of reducing the multivariate case to the univariate case, randomized list-decoding algorithms for RM codes were given in and . The algorithm in Sudan et al. (1999) is an improvement of the algorithm in , it is applicable to codes RM/sub q/(u,m) with u
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Etzion T. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2006,52(11):4867-4879
The stopping redundancy of the code is an important parameter which arises from analyzing the performance of a linear code under iterative decoding on a binary erasure channel. In this paper, we will consider the stopping redundancy of Reed-Muller codes and related codes. Let R(lscr,m) be the Reed-Muller code of length 2m and order lscr. Schwartz and Vardy gave a recursive construction of parity-check matrices for the Reed-Muller codes, and asked whether the number of rows in those parity-check matrices is the stopping redundancy of the codes. We prove that the stopping redundancy of R(m-2,m), which is also the extended Hamming code of length 2m, is 2m-1 and thus show that the recursive bound is tight in this case. We prove that the stopping redundancy of the simplex code equals its redundancy. Several constructions of codes for which the stopping redundancy equals the redundancy are discussed. We prove an upper bound on the stopping redundancy of R(1,m). This bound is better than the known recursive bound and thus gives a negative answer to the question of Schwartz and Vardy 相似文献