An all-digital coherent-like BFSK demodulator

An all-digital coherent-like binary frequency shift keying (BFSK) demodulation based on the use of a multi-bit shift register, two multi-bit XOR gates and a mean value filter is presented. The demodulator is fabricated in SMIC 65-nm CMOS process with a die area of 0.015 mm². The demodulator consumes 1.44 mW with 1.2 V of voltage supply and 32 MHz of sample clock. The measured bit error ratio (BER) performance is better than that of other non-coherent demodulators. The proposed demodulator exhibits better performance in terms of composite indicator compared to other demodulators. Another advantage of the all-digital demodulator defined using Verilog HDL is that it can also be implemented on Field Programmable Gate Array (FPGA) platform rapidly to recover FSK signals with different carrier frequencies and data rates. These results make the all-digital demodulator suitable for the application in communication and consumer electronics.     

BFSK的循环平稳特性分析

首先介绍了循环平稳的基本概念,给出了BFSK的信号模型,推导了BFSK信号的循环相关函数和循环谱的数学表达式,分析了其循环平稳特性,说明了其具有循环平稳性,最后给出了计算机仿真实验。仿真结果表明,BFSK信号具有循环平稳特性,属于循环平稳信号。仿真同时说明了利用信号的循环平稳特性进行参数估计具有较高的循环频率分辨率。     

基于差分检波的集群通信BFSK解调算法研究

本文首先阐述分析差分检波BFSK（二进制频移键控）解调算法,计算出算法中分数延迟滤波器的系数。然后通过matlab的simulink工具建立调制解调算法模型,利用模型分析差分检波解调算法的性能,综合解调性能和资源占用率来优化分数延迟滤波器定点系数。通过误码率对比分析,最终得到一个占用资源较少且解调性能优异的算法模型。为硬件语言实现BFSK解调算法以及FPGA仿真验证打下基础。     

一种无线传感器网络超低功耗接收器设计

针对无线接收器功耗影响无线传感器网络生命周期的问题,在OOK超再生接收器的基础上,设计了一种无线传感器网络超低功耗无线接收器——BFSK超再生接收器;介绍了该接收器的体系结构,给出了该接收器的电路设计。该接收器在保留OOK超再生接收器超低功耗的基础上,采用f1和f2两种频道来确定输出是"0"还是"1",使得传输速率得到了较大提高。实验结果表明,当传输速率为250kbit/s时,2.4GHz接收器灵敏度为-86dB.m,功耗仅为215μW。     

CDF and MGF based analysis over Rayleigh TWDP shadowed fading channel for indoor communication

Recently, the two-wave with diffuse power (TWDP) distribution has been extensively used to model the shadowing in multipath-faded/shadowed indoor environment. In this article, novel expressions for joint moments, mean, second moment, variance and cumulative distribution function for Rayleigh TWDP shadowed fading model are derived. By using the derived expression of mean and variance, the expression for amount of fading is obtained. Also, the outage probability, moment generating function and average bit error rate (ABER) for various modulation schemes namely binary phase shift keying (BPSK), binary frequency shift keying (BFSK), minimum shift keying (MSK), differentially coherent phase shift keying (DCPSK) and non-coherent frequency shift keying (NCFSK) are calculated. The derived expressions for cumulative distribution function, outage probability and ABER are presented in analytical format and have been numerically evaluated. Moreover, the numerical results of ABER using MSK and DPSK modulation schemes is compare with results of Rayleigh Gamma composite fading model. The study shows that better outage probability (0.01) is observed at 40dB average signal to noise ratio (SNR) with 5dB lowest threshold SNR, however, at higher threshold SNR (>5dB) with fixed average SNR (40dB), poor outage probability performance are obtained. Further, at higher shadowing (10dB), for fixed average SNR (15dB), minimum error probability (10^?4) is observe, while at lower shadowing (less than 10dB), higher error probability (greater than 10^?4) is observed that represents poor BER performance.     

An 863-870 MHz spread-spectrum FSK transceiver design for wireless sensor

Simulation results of a 863-870 MHz frequency-hopped spread-spectrum (FHSS) transceiver with binary frequency shift keying (BFSK) modulation at 20 kb/s for wireless sensor applications is presented.The transmit/receive RF front end contains a BFSK modulator, an upconversion mixer, a power amplifier (PA), and an 863-870 MHz band pass filter (BPF) at the transmitter side and a low-noise amplifier with down conversion mixer to zero-IF, a low-pass channel-select filter, a limiter and a BFSK demodulator at the receiver side. The various block parameters of the transmit/receive RF front end like noise figure (NF), gain, 1 dB compression point (P-1 dB), and IIP3 are simulated and optimized to meet low power and low cost transceiver specifications.The transmitter simulations show an output ACPR (adjacent channel power ratio) of −22 dBc, 3.3 dBm P-1 dB of PA, and transmitted power of 0 dBm. The receiver simulations show 51.1 dB conversion gain, −7 dBm IIP3, −15 dB return loss (S11), and 10 dB NF. Low power arctangent-differentiated BFSK demodulator has been chosen and the BER performance has been co simulated with the analog receiver. The complete receiver achieves a BER of 10⁻³ at 10.5 dB of EbtoNo. The transceiver simulations show an RMS frequency error of 1.45 kHz.     

基于Monte Carlo模型的FFH/BFSK合并技术研究

分析了FFH/BFSK接收机的两种合并方式:平方律线性合并和具有自适应增益控制(AGC)的平方律非线性合并;在部分频带噪声干扰下,使用Monte Carlo模型对这两种合并方式进行仿真得到误码率曲线,仿真结果与理论误码率吻合,并得出结论:在热噪声功率受限的情况下,使用AGC合并能有效的抑制部分频带噪声干扰.     

LDPC码在非相干BFSK系统中的性能分析

通过理论分析和计算机仿真研究了LDPC码在非相干BFSK系统中的性能.首先证明单输入双输出的非相干BFSK系统满足信道对称条件,然后分别利用离散密度进化(DDE)和高斯近似(GA)算法给出了LDPC码的性能下界,后者与前者相比性能非常接近而且计算量要小很多.通过仿真得到几种常用LDPC码的性能并与译码门限以及香农极限进...