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本文就采用差分相移键控调制的直接序列扩频电台的问题,提出我们的设计及测试报告,这种电台利用无线专用交换机(PBX)相互通信。描述了采用声表面波(SAW)滤波器的发射机和接收机的设计和实施,该SAW滤波器与用户扩频码相匹配。这种接收机的性能与存在加性白高斯噪声时差分相移键控(DPSK)接收机的理论性能相比不超过1 dB。还说明了在多径表落谷深达50dB的室内环境下接收机的性能。通过等增益分集合并器可以克服室内信道多径表落,这种等增益分集合并器对于使用DPSK调制是适合的。证实了室内平均功率的衰减是随距离的四次方成反比。同时,本文还使用一部具有不同扩频码序列的干扰发射机来研究系统的多址性能。
This paper presents our design and test reports on the issue of direct sequence spread spectrum spread spectrum modulated by differential phase-shift keying. The stations communicate with each other using a PBX. Describes the design and implementation of a transmitter and receiver employing a surface acoustic wave (SAW) filter that matches the user spreading code. The performance of this receiver does not exceed 1 dB compared to the theoretical performance of a Differential Phase Shift Keying (DPSK) receiver in the presence of additive white Gaussian noise. It also illustrates the performance of receivers in an indoor environment where the multipath meter reaches a depth of 50 dB. Indoor channel multipath entry can be overcome by an equal gain diversity combiner, which is suitable for use with DPSK modulation. It is confirmed that the average indoor power attenuation is inversely proportional to the fourth power of the distance. At the same time, we also use a jamming transmitter with different spreading code sequences to study the system’s multiple access performance.