Digital Portable Transceiver Using GMSK Modem and ADM Codec

Digital mobile radio transmission techniques and integrated circuit devices have been developed for application to a digital portable transceiver utilizing narrow-band GMSK modulation and ADM voice coding. Design and performance of a quadrature type GMSK modulator and a single-chip coherent demodulator as the GMSK modem are described. To overcome slow fading, encountered in portable applications, switching diversity using a jitter detection type sensor is Proposed and shown to be effective. An experimental Portable transceiver, developed to demonstrate hardware feasibility, is also described.     

A quad-band 8PSK/GMSK polar transceiver

The addition of 8PSK modulation to the GSM standard creates the need for architectural modifications to achieve necessary performance while maintaining a cost-effective solution. A large-signal polar modulation transmitter allows the use of an efficient nonlinear power amplifier (PA) for both GMSK and 8PSK. Digital interfaces are used for both receiver and transmitter, with analog options available for compatibility with older technology baseband systems. The receiver section of the transceiver is programmable to operate in direct conversion mode or multiple VLIF modes. All analog and digital filtering necessary to define the final channel is included. The transmit section of the transceiver uses an all digital system with a fractional-N digital modulator for the phase path. The amplitude path uses a Powerstar PA with both the ramp and the amplitude modulation applied to the collector. The transceiver meets or exceeds all specifications for both GMSK and 8PSK in all four cellular bands (850/900/1800/1900).     

便携式红外收发器的设计与实现

介绍了一种以C8051F310单片机为控制核心,可实现红外数据通信的便携式收发器。对其基本原理和标准规范进行了说明,给出了设计思路和硬件电路。阐述了电源处理各模块的特性和实现过程。同时给出了符合IrDA标准通讯协议的设计方法。     

基于FPGA的AIS中频收发信机设计及实现

针对海事自动识别系(Automatic Identification System,AIS)收发信机的信号处理主要采用专用芯片实现的现状,提出了一种中频数字化的替代方案,采用FPGA完成AIS中频收发信机的信号处理.重点研究了突发GMSK中频信号的调制、差分解调、位同步和帧同步的设计方法及实现过程.测试结果表明,采用并行化的数字信号处理,增强了设备的灵活性和可靠性,并提高了设备的性能.     

X波段便携式战场侦察雷达收发系统低功耗设计

便携式战场侦察雷达具有低截获、高灵敏度、结构灵巧、发射功率小、架拆迅速、配置人员少等特点,其不仅适用于战场前沿,也适用于和平时期的很多场合,因此越来越被人们关注。收发系统作为便携式战场侦察雷达的重要组成部分,其功耗为工程设计的重点。便携式战场侦察雷达收/发系统的设计主要任务是在符合整机指标的前提下,如何降低功耗、体积、重量。本文论述了一种便携式战场侦察雷达收/发系统低功耗设计技术,经测试该系统功耗小于20W     

基于ARM和nRF905的无线数据收发系统

为无线随动控制系统的数据传输所设计的无线数据收发系统,采用ARM LPC2148和nRF905构成,工作在433MHz的ISM频段,最远传输距离可达1000m,数据速率为50Kb/s,工作电压为3.3V,在发射功率为-10dBm时,电流消耗为11mA,低功耗模式时电流消耗仅为42μA。系统采用DSS＋PLL频率合成技术和GMSK调制,信道数最多可达170个,能够满足需要多信道工作的特殊场合使用。     

基于DS18B20的短距无线温度检测系统

基于一种新型单线可编程数字温度传感器DS18820的测温原理,以低功耗的MSP430F1611单片机为微控制器,设计了一种的短距无线温度检测系统,并通过无线模块nRF401实现数据的无线收发。给出了微控制模块、LCD显示模块、无线收发模块和温度传感器模块的设计以及系统的软件开发。实验结果表明：系统实现了短距、多点的温度检测;利用无线收发模块和CLD显示模块,节约了现场调试时间,实现了系统的便携式设计并提高了温控系统的稳定性;利用MSP430单片机的超低功耗以及DS18820的单线接口方式,实现了整个系统的低功耗设计,并简化了系统的结构。     

Analysis and design of a frequency-hopped spread-spectrumtransceiver for wireless personal communications

Personal communications services (PCS) require low-power radio technologies. One such transceiver architecture employing frequency-hopped spread-spectrum techniques is presented. System features such as antenna diversity with equal-gain combining and sequential hop combining are incorporated into the transceiver design to achieve robust wireless digital data transmission over fading channels. A direct-conversion architecture from radio frequency (RF) to baseband reduces the overall power consumption by eliminating intermediate frequency (IF) components. High-rate frequency hopping with frequency-shift keying (FSK) modulation is implemented using a direct digital frequency synthesis technique. A multiplierless correlation FSK detector, suitable for direct-conversion receivers, has been designed for quadrature noncoherent detection. Robust acquisition algorithms based on energy detection and pattern matching and tracking architectures using digital phase-locked loops are also described for system synchronization. The proposed transceiver is well-suited for low-power PCS applications and other portable wireless communications     

便携式LPI战场侦察雷达收发系统的微型化设计

便携式战场侦察雷达具有小功率、低截获、高灵敏度、结构灵巧、架拆迅速、配置人员少等特点,不仅适用于战场前沿,也适用于和平时期的很多场合,因此越来越被人们关注。收发系统作为便携式战场侦察雷达的重要组成部分,其功耗、体积、重量均为工程设计的重点。文章论述了收发系统集成模块化及微型化的设计方法。该收发系统按集成模块化设计后总重量为4.4kg,体积为300mm×200mm×100mm。     

A Low-Power Fullband 802.11a/b/g WLAN Transceiver With On-Chip PA

A low-power fullband 802.11a/b/g WLAN transceiver in 0.15-mum CMOS technology is described. The zero-IF transceiver achieves a receiver noise figure of 4.4/4 dB for the 2.4-GHz/5-GHz bands, respectively. The corresponding sensitivity at 54-Mb/s operation is -72 dBm for 802.11g and -74 dBm for 802.11a using actual PER measurement. An on-chip PA delivers 20 dBm output P1-dB. A new I/Q compensation scheme is implemented in local oscillator (LO) and an image rejection of better than 52 dB is observed. The transmitter delivers 10/1.5 dBm (2.4-/5-GHz) EVM-compliant output power for a 64-QAM OFDM signal at 54-Mb/s. The power consumption is 117/135 mW (1.8-V) in the receive mode and 570/233.1 mW in the transmit mode for 2.4/5 GHz, respectively. The low power consumption, high integration and robustness (-40 to 140degC) make this transceiver suitable for portable applications     

A multicarrier GMSK modulator

A multicarrier Gaussian minimum shift keying (GMSK) modulator has been developed and implemented. The design contains four GMSK modulators, which generate GMSK modulated carriers at the specified center frequencies. Utilization of the redundancy in the stored waveforms reduces the size of the GMSK trajectory look-up table to less than one-quarter of the original size in the modulator. Conventionally, the power ramping and output power level controlling are performed in the analog domain. A novel digital ramp generator and output power level controller perform both the burst ramping and the dynamic power control in the digital domain. The power control is realized by scaling the ramp curve, which follows a raised cosine/sine curve. The four GMSK modulated signals are combined together in the digital domain. The digital multicarrier GMSK modulator is designed to fulfil the spectrum and phase error specifications of the GSM 900 and DCS 1800 base stations     

一种低运算量的基于DDC的GMSK解调方案

在分析GMSK常用解调方案的基础上,提出了一种基于数字下变频器件(DDC)输出相位的差分负反馈解调方案,并给出其与常用解调方案的性能仿真分析和比较。分析结果表明,该方案在保证DDC晶振稳定度的条件下性能良好。同时该方案只需要在最佳抽判时刻进行运算,大大减小了运算量,降低了对处理器的速率要求的同时也降低了功耗,特别适合于便携式跳频通信系统。     

A Novel Serially Concatenated GMSK System for Satellite Communications

A novel serially concatenated GMSK system is proposed for satellite communications subject to low SNR, limited power and spectrum resources. First, we design a Nonrecursive continuous-phase encoder (NRCPE) based GMSK based on the Rimoldi's decomposition. Then, a corresponding pilot-aided quasi-coherent demodulation algorithm is developed, whose basic principle is that a modified BCJR-based detection performs on the received signals with initial and ending trellisstates being determined using the very limited pilot overhead. Finally, we choose proper modulation parameters for the NRCPE based Gaussian minimum shift keying GMSK signaling according to the trade-offs between the power and spectral efficiency. The simulation results show that the LDPC coded GMSK system using the proposed algorithm can achieve excellent performance and can also work well in the presence of the large Doppler shifts and some burst errors.     

GMSK信号在雷达中的应用研究

GMSK信号即高斯最小移频键控编码信号,本文研究了GMSK信号在雷达中的应用,介绍了其特点、产生方法和码型优选方法,针对GMSK信号的多普勒敏感性,提出了一种多普勒补偿技术,提高了系统的多普勒容限。在实际应用中采用这种新的码型及重频捷变,使雷达系统具有很高的抗截获性能。     

Single-channel blind equalization for GSM cellular systems

This paper focuses on the study of blind equalization global system for mobile communications (GSM) systems using a single antenna. In order to utilize the well-known linear system model in conventional studies of blind equalization, an equivalent baseband quadrature amplitude modulation (QAM) approximation is used for the nonlinear GMSK signal in GSM systems. Since the GMSK signal in GSM has very little excess bandwidth to warrant oversampling, a derotation scheme is developed to create two subchannels for each received GMSK signal sampled at the baud rate. Linear approximation of the GMSK signal makes the traditional QAM blind equalization system model applicable for GSM. Derotation induces channel diversity without an additional antenna and reduces the number of necessary radio frequency (RF) receivers (sensors) without increasing hardware or computational costs. Several second-order statistical and higher order statistical methods of blind equalization are adopted for GSM signals     

一种基带GMSK信号相关器及其输出概率分布

该文提出一种基带GMSK信号相关器,并从GMSK解调信号的相位概率分布函数以及独立同分布随机变量和的概率分布函数出发,给出了该相关器的自相关峰和互相关峰的概率分布函数。从概率论与数理统计出发,推导了一种统一的数字相关器(数字匹配滤波器)的自相关峰和互相关峰的概率分布函数。数值计算结果表明,在相同条件下,该基带GMSK信号相关器的误检概率比数字相关器的低近一个数量级。     

A comparative study of narrowband microcellular speech transmissionschemes

Experiments are conducted on a number of mobile radio systems that are suitable for operation in nondispersive microcellular networks. It becomes apparent that the selection of the type of modem and the number of its levels, the choice of speech codec to be used, and whether to deploy a channel codec, depends on the channel signal-to-noise ratio (SNR) and teletraffic demand, if the power consumption of the handheld portable is to be minimized. Following the implications of the authors' limited number of experiments, they generalize their findings to some of the requirements of an adaptive transceiver that might be deployed in the next generation of mobile radio networks     

A 270-kb/s 35-mW modulator IC for GSM cellular radio hand-heldterminals

The modulator IC is a mixed analog/digital transceiver component in a chip set that is designed for the hand-held terminals of the pan-European 900-MHz Groupe Special Mobile (GSM) digital cellular radio network. The concept of the radio-frequency environment in which the circuit is used is explained, focusing on the differences in existing systems. The architecture and different functions of the modulator circuit and details of the digital and analog processing in the transmission mode are discussed. The receiving mode, which is mostly based on analog processing, is highlighted. The device generates Gaussian minimum-shift-keying (GMSK) modulation and converts the received signal to 8-b words after filtering. The modulator IC uses digital waveform generation and a quadrature signal representation. This device is implemented in a 1.5-μm CMOS technology. The power consumption is less than 35 mW from a 5-V supply     

一种基于RFID的便携式智能语音播放器设计

针对传统的红外电子导游系统的不足,采用RFID技术设计并实现了一种便携式智能语音播放器。在给出RFID便携式智能语音播放器的总体设计方案之后,分别对RFID模块、无线信号收发模块、控制器和解码模块进行了详细设计并给出了电路设计原理图;该播放器不仅体积小、感应灵敏,而且可以广泛应用在不同领域。