全文获取类型
收费全文 | 81篇 |
免费 | 0篇 |
专业分类
轻工业 | 2篇 |
无线电 | 70篇 |
一般工业技术 | 4篇 |
冶金工业 | 4篇 |
自动化技术 | 1篇 |
出版年
2020年 | 1篇 |
2009年 | 2篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 8篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有81条查询结果,搜索用时 15 毫秒
1.
Error rates for a narrowband digital FM system with discriminator detection in a land mobile radio channel characterized by fading and Doppler frequency shift are obtained using a new analytical method. The fading rate is assumed to be much slower than the bit rate so that signal distortion through a narrow bandpass filter can be analyzed via a quasistatic approach. An experiment was conducted using a Rayleigh fading simulator, and the error rate measurements are shown to agree well with the calculated results, except at high SNR (signal-to-noise ratio) where an irreducible error rate was observed 相似文献
2.
A gamma distribution is used to model the received optical power fluctuation in a digital fiber-optic system affected by modal noise. New recursive formulas for the moments of the receiver output current are obtained which can be used in the Gauss quadrature rule (GQR) approximation of the error probability integral. Error rates have been calculated for varying degrees of modal noise disturbance 相似文献
3.
An edge detecting scheme for coded mark inversion (CMI) line codes which can reject wrong slot errors is proposed. This scheme looks at data transitions over one-and-a-half symbol durations and makes a binary decision based on the most likely transition pattern. An analysis and measurement results for the bit-error-rate performance of this scheme over an optical fiber link which show improvements in the detector tolerance against symbol timing jitters are presented 相似文献
4.
Tjhung T.T. Choon Tiong Ng Chun Sum Ng 《Vehicular Technology, IEEE Transactions on》1995,44(1):140-145
Reed Solomon codes with interleaving are used in a binary FM transmission affected by Rayleigh fading as encountered in land mobile radio. A new decoding algorithm is proposed which can be implemented in simple hardware. The error performance of the binary FM system with the RS code with one and two degrees of interleaving is measured. A significant reduction of error rate floor as a function of fading speed is noted and discussed 相似文献
5.
Approximate results for the bit error probability (BEP) of binary phase shift keying (BPSK) in the presence of a noisy carrier phase reference are presented. The results show correctly the behavior or the BEP as a function of SNR. The accuracy of the approximations is verified by simulations and numerical integration of the BEP formulas. The results are compared with existing bounds 相似文献
6.
SER performance evaluation and optimization of OFDM system with residual frequency and timing offsets from imperfect synchronization 总被引:1,自引:0,他引:1
This paper deals with the effects of residual timing and frequency offsets on the symbol error rate (SER) performance of an orthogonal frequency division multiplexing (OFDM) system. The synchronization of an OFDM system generally consists of a coarse frequency and timing acquisition stage and a refine stage. Due to the presence of Gaussian noise, channel distortions and implementation losses of synchronization and equalization algorithms, residual frequency and timing offsets always exist for an OFDM receiver. The residual frequency and timing offsets are proven to be Gaussian distributed, with their corresponding variances determined. The reception process of an OFDM signal with frequency and timing offsets is analyzed. A closed-form analytical result on the SER of an OFDM system with residual synchronization errors is derived. Computer simulations and analyses show that the frequency and timing offsets affect the OFDM subcarriers differently. With this observation, a new technique is proposed to minimize the SER of the OFDM systems by adjusting the distribution of transmission power among the subcarriers. 相似文献
7.
In earlier works on transmitter power control in cellular radio systems, the problem of whether a signal‐to‐interference ratio (SIR) threshold is achievable is determined by apparently different rules for homogeneous and heterogeneous SIR systems. In this paper, we present a unified and more universal framework for both cases. We also highlight the conditions under which a given SIR threshold vector for the heterogeneous SIR system is achievable, although so far there is no general solution to this problem. 相似文献
8.
Two new series representations for the Rice functionIe (k, x) are presented. One of the series involves the modified Struve functions and the other involves the modified Bessel functions. These two series complement each other in their convergence speeds as functions of the values ofk andx . The truncation error bounds are derived for both series. Therefore, they can be used alternatively with high efficiency and known precision. 相似文献
9.
Bit error rate (BER) performance of differential 16STAR-QAM in frequency-selective Rician fading channels with diversity reception is theoretically analysed for three different types of delay profiles: double spike, one-sided exponential and Gaussian profiles. The effect of time delay between line-of-sight (LOS) and multipath components is also included in the analysis, and is shown to degrade the system performance significantly 相似文献
10.
Spectra of digital signals transmitted by combined amplitude and frequency modulation are derived. Cumulative spectral-distribution curves are presented for certain values of f.m. deviation and a.m. index, and the results are compared with biternary f.m. transmission. 相似文献