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改进环路结构的Gardner定时恢复算法李维; 江虹; 伍春; 邓皓文【期刊名称】《《计算机应用》》【年(卷),期】2019(039)010【总页数】5页(P3013-3017)【关键词】位同步环路结构; 改进型Gardner算法; 加权平均; 同步建立时间; 同步性能【作者】李维; 江虹; 伍春; 邓皓文【作者单位】西南科技大学信息工程学院四川绵阳621010; 西南科技大学国防科技学院四川绵阳621010【正文语种】中文【中图分类】TN911.70 引言定时恢复是数字解调技术中的关键环节,对解调系统的性能有着重要的影响[1-2]。
早期的Gardner定时同步算法能够较好地解决接收端接收到的信号与本地时钟信号不一致的问题,但存在同步建立时间长、稳定性较差等缺陷,其环路性能难以满足当前高速解调系统的需要[3-4]。
随着数字解调技术的快速发展,同步建立时间短、环路稳定性高的定时恢复算法成为一项迫切需求[5]。
为此,文献[6]利用相邻码元符号相同时,对误差检测器检测出的误差进行取反,得出了一种改进的Gardner算法,记为改进的Gardner定时恢复算法1(modified Gardner timing recovery Algorithm 1,mGA1);文献[7]对mGA1算法进行了改进(记为mGA2算法),降低了算法复杂度。
上述两种方法在一定程度上提高了符号同步的性能,但仍然存在算法复杂度高、硬件资源消耗大、环路稳定性较差等问题。
为克服上述方法的不足,文献[8]提出了一种类似锁频锁相(Frequency and Phase Lock Loop, FPLL)的改进Gardner定时恢复算法(记为mGA3算法),其同步性能与mGA1算法和mGA2算法相比有了进一步的提升；但该算法在同步过程中,符号收敛速度较慢,定时抖动较大。
为提高数据处理速度,文献[9]在原有串行定时同步的基础上,对Gardner算法进行了改进,提出了一种并行Gardner定时同步算法,在一定程度上提高了数据处理的速度；但环路分数间隔收敛时抖动较大,不稳定,且占用较多的乘法器、加法器资源。
48 | 电子制作 2021年05月容量大、业务适应性强、覆盖范围广、性能稳定、机动灵活、成本低等优点已成为现代通信的重要方式，在应急通信、军用通信、民用通信及中继通信等方面具有广阔的应用前景。
然而，在全数字传输系统中，由于接收端本地采样时钟与发送端时钟的相互独立，使得全数字接收机对信号的最佳采样时刻出现偏差，接收机采样点不能调整到最佳采样时刻，从而造成整个系统误码率性能的下降。
同时，接收端和发送端时钟的频率还存在一定的误差，当误差随时间累积到一定程度时也会给系统性能带来严重的影响。
对于TDM/TDMA 系统，要求信号在星上保持着严格的时间对齐关系，然而信号在传输及恢复过程中会受到多种不确定因素的影响，进而引定时误差，显得至关重要，尤其对于TDMA 系统。
在TDMA 系统中，信号的定时同步对时隙的正确接收有重要意义，位定时的偏移会引起星座图相点的偏移，严重时甚至无法解调。
换言之，对任何数字通信系统而言，性能良好的同步系统是实现后续信号准确接收解调的关键。
因此，研究定时同步技术在卫星通信中起着重要的作用。
基于上述分析，我们研究了适用于TDM/TDMA 系统的定时同步技术，以期实现最好的接收性能。
同的定时同步环路。
对于TDMA 系统，信号是突发数据流，突发持续时间短，需要定时同步环路快速入锁，对锁相精度和锁相时间都具有较高的要求。
针对TDMA 系统突发信号数据短、不连续的特点，我们需要研究快速入锁的定时同步算法。
对于TDM 系统，信号是时间连续数据流，对入锁速度没有过高的要求。
基于上述TDMA 和TDM 两种系统不同的特点，在定时同步环路方面我们分别设计了适用于TDMA系统的前馈型算法和适用于TDM 系统的反馈型算法。
反馈型算法锁相精度高，但是锁相速度慢，甚至有“假锁”现象，不适合TDMA 突发信号快速入锁的需要。
前馈型算法需要的捕获时间短，适合TDMA 突发信号的处理。
本文所研究www�ele169�com | 49平方滤波定时误差估计后基于重采样原理的定时误差消除环路，分别包括定时误差估计器、内插滤波器、环路滤波器等。
Nexus7Ⅱ原生已有一个Recovery，但功能比较单一，只是用于官方的OTA升级、恢复出厂设置，第三方的Recovery则弥补了如清除数据，刷入第三方系统（安装zip升级包），备份和还原系统等等其它功能的缺陷。
CMW-XDA论坛原帖/showthread.php?t=2381544 CWM官网/rommanagerTWRP-XDA论坛原帖/showthread.php?t=2380100 TWRP官网http://www.teamw.in/project/twrp2CWM刷机模式是著名的第三方Recovery，全称ClockworkMod Recovery，早期玩安卓的机友对它并不陌生，是非触屏版的Recovery，只能用物理按键进行操作，比如音量键、电源键等，当然，现在也出了触屏版的CWM；然而对于只有一个电源按键的设备来说，传统的ClockworkMod在上面无法操作，所以像TWRP 这样的触屏版Recovery也就孕育而生，全称Team Win Recovery Project。
以下图片从左到右分别为Nexus7Ⅱ的原生Recovery、CWM、TWRP。
你没有看错，原生Recovery的界面确实只是一个倒地躺下的机器人。
在CWM中，Nexus7Ⅱ的音量加减键的功能是向上、向下、电源键是确认，而每个功能菜单里都有一个返回项“Go Back”，只需要用音量键把光标定位至返回项，按一下电源键即可返回。
刷入前提：Nexus7Ⅱ需要先解锁什么？！不知如何解锁？参照这里二代Nexus7Ⅱ一键解锁ROOT工具--by爱折腾/forum.php?mod=viewthread&tid=6514095刷入方法：无论是刷CWM，还是刷TWRP，方法都一样，把镜像文件放入adb工具包里，再执行刷入命令即可，以刷CWM为例：PS：所谓adb工具包，其实就是总共包括4个文件，分别为adb.exe，AdbWinApi.dll，AdbWinUsbApi.dll和fastboot.exe 网上搜搜便可以得到，当然文末也有下载地址。
Gardner Symbol Timing RecoveryThe Gardner Symbol Timing recovery demo illustrates symbol timing recovery for an 8-PSK modulated and filtered signal transmitted over a varying delay channel.This document highlights the following aspects of the demo:∙Structure of the demo∙Key points of the demo∙Visible results of the demo∙Experimenting with the demoStructure of the DemoThe demo uses various blocks from the Communications Blockset, Signal Processing Blockset and Simulink to model an 8-PSK transmitted signal. The demo includes the following blocks:∙Random Integer Source block that generates uniformly distributed integers in the range [0, M-1], where M is the alphabet size.∙M-PSK Modulator block followed by a Root-Raised Cosine Transmit filter block that modulates and then up-samples and pulse shapes the signal stream fortransmission.∙The channel consisting of a Variable Integer Delay block and an AWGN Channel block. The Variable Integer Delay block introduces random integer delays lessthan the up-sampling factor and the AWGN Channel block can vary the SNRlevel based on user input.∙At the receiver end, a receive filter matched to the raised cosine pulse shape is followed by the Gardner Symbol Synchronizer subsystem block. Afterappropriate demodulation, the output is fed to the displays for analysis purposes. Key points of the DemoThe demo showcases the Gardner Symbol Synchronizer subsystem. This block allows for tracking a static difference in the receiver source symbol frequency from the actual transmitter value (expressed as a percentage of the transmitter source symbol frequency). The difference in the receiver symbol frequency from that of the transmitter can be adjusted by modifying the “Receiver source symbol frequency” parameter of the Gardner Symbol Synchronizer block.The block works for over-sampled signals by synchronously sampling the incoming signal. It does not interpolate the received signal and so shows deteriorated performance with fractional sample delays.Since the block is subsystem-based, it allows for straightforward inspection of the implementation, at the expense of using triggered and enabled subsystems to work with the derived clocks.Visible results of the DemoAs the introduced delay of the channel is changed for every frame, the error signal shows periodic bursts where the synchronizer has to re-track the signal. One can increase the size of the frame to observe the settling period. The stable value of the error is a measure of the amount of difference (as a percentage) in the transmitter and receiver frequencies that the synchronizer has recovered from.On running the simulation model, the scatter plot shows the recovered signal points before demodulation and the BER meter shows the error performance for the level of noise selected.The symbol clock scope shows the recovered clock at the symbol rate. Note the initial jitter and then the gradual settling phase over a frame to indicate the tracking behavior. Experimenting with the DemoOn loading, the demo initializes a set of variables that control the simulation. The user is encouraged to play with the value of these variables to see their effects on the demo. Some of the ways to modify the demo include:∙Vary transmit and receive filter characteristics – rolloff parameter, group delay.∙Vary the receiver symbol frequency to see if the block can still track the signal and demodulate appropriately.∙Vary the AWGN noise levels.∙Vary the simulation frame size. Vary the delay to be constant for the length of the simulation or multiple frames.∙Use a different modulation scheme – say QPSK or 16QAM, which may require you to change some of the blocks also.。
连续传输前馈符号定时恢复算法研究及实现寇辰光; 张有志; 陈敬乔【期刊名称】《《无线电工程》》【年(卷),期】2019(049)011【总页数】6页(P1014-1019)【关键词】连续传输; 前馈; 定时恢复; 插值滤波; FPGA【作者】寇辰光; 张有志; 陈敬乔【作者单位】中国电子科技集团公司第五十四研究所河北石家庄 050081; 海装装备项目管理中心北京 100166【正文语种】中文【中图分类】TN9290 引言符号定时恢复是接收端信号解调的关键环节，准确的定时同步可以得到码元符号的最佳采样点，为后续解调步骤提供可靠基准[1]。
按照传输和获取同步信息方式的不同，定时恢复主要可以分为数据辅助和非数据辅助2种方式。
数据辅助法会占用额外的发射功率和信道带宽，从可靠性和经济实用性等方面来看都不够理想；非数据辅助法不需要占用额外资源，适合大多数字通信系统，但是对接收端的要求较高，实现较为复杂。
当前非数据辅助的定时恢复法根据实现结构不同，主要可以分为反馈结构和前馈结构2种[2-5]，反馈结构中采用锁相环相关原理[6-8]，可以实现较为精确稳定的定时同步，但是结构实现相对较为复杂，且需要消耗较长的锁定时间，不适用于突发传输的定时恢复[9]，一般用于连续传输定时；前馈结构不同于反馈式的闭环结构，采用开环结构[10-12]快速跟踪信号相位变化，具有捕获时间短的优势，但是定时性能不如反馈结构精确。
前馈结构可以分为根据定时误差直接抽取最佳采样点和根据定时误差进行插值滤波[13-16]获取最佳采样点2种方法，进行插值滤波获取最佳采样点的前馈方法在处理连续传输的定时同步时难以实现，因此多用于突发传输的定时同步。
本文针对连续传输的背景提出了插值滤波的前馈定时方法，通过仿真实验得到该算法的性能曲线，并基于FPGA硬件平台对该算法进行了实现，解决了数据切换点处符号定时不准确的问题。
1 前馈定时方法1.1 直接抽取前馈定时方法通过直接抽取方式获取符号最佳采样点的前馈定时同步主要包括定时误差估计和数据抽取2部分，处理框图如图1所示。
Timing Advance ProcessorEG DYNAMICuser manualver. 2.7.1 dated 2021-06-22This instruction can be also downloaded from:https://europegas.pl/en/wsparcie-techniczne/Table of content1. Timing Advance Processor “EG Dynamic” description (3)2. Description of signal connections (4)2.1. Power supply source (4)2.2. MAP signal (optional) (5)2.3. TPS signal (5)2.4. Activation signal (5)2.5. Crankshaft position sensor and camshaft position sensor signals (5)2.6. Diagnostic interface plug (6)2.7. Proper installation of TAP EG Dynamic ECU (7)3. Software description (8)3.1. Right panel – actual value of system parameters: (8)3.2. Left panel – Settings bookmark (9)3.3. Middle panel – Maps (11)4. EG Dynamic TAP Calibration step-by-step (12)Hint: Click with Your left mouse button on any of above chapters to go to its page.1. Timing Advance Processor “EG Dynamic” description.EG DYNAMIC Timing advance processor dynamically changes the moment of engine's ignition while it is running on LPG/CNG fuel to improve combustion process efficiency. This way vehicle's engine works more dynamically. Power losses during acceleration are practically eliminated. Advance of ignition is very important when engine runs on CNG because CNG-air mixture combustion time is much longer comparing to combustion time of petrol-air mixture. Usage of Timing Advance Processor also eliminates risk of backfiring and significantly reduces gas consumption. We can say that it is temporarily adapting the original vehicle's ignition system to use LPG/CNG so the difference between driving on both fuel is practically imperceptible.Main advantages of EG DYNAMIC Timing Advance Processor are:∙It is no longer necessary to keep different TAP models depending on type of the crankshaft/camshaft position signal type in particular car.EG DYNAMIC is scanning, learning and supporting all inductive and digital crankshaft and camshaft signals.∙Very easy calibration and configuration process with usage of multipliers user interface.∙Possibility of dynamic and smooth advancing or delaying of ignition angle up to +-30 degrees, depending on the current values of TPS position, RPM and MAP signals.∙Single TAP device supports one inductive sensor and up to two digital sensors simultaneously (STD version) or three digital sensors simultaneously (3D version). It is possible to connect them in any configuration.∙Flexible adjustment of TAP activation moment . Advancing of ignition depends on actual values of RPM and TPS signal and can be activated by “+” or by “-” signal.∙Deactivation of TAP and restoring the original RPM signal in case of emergency can be done easily by pulling out the fuse from fuse holder.2. Description of signal connections2.1. Power supply sourceAttention:Device is destined to be used in cars with +12V power supply installation.Power supply should be connected to such a place from where the device is powered all the time while engine is running. It should be present from the moment of turning ignition key in ACC position until the engine will be switched off. It is unacceptable to connect this line to places where +12V might dissapear: for example, where voltage may drop out while engine is in the cut-off conditions.Hint: In OSCAR-N SAS ECU we should connect it to the red-white wire connected to the +12V ignition from the key.Power supply wire is equipped with 1A circuit fuse, which after removal allows us to disable TAP operation and restore the original RPM signal without necessity of shortening the original camshaft/crankshaft signal wires.2.2. MAP signal (optional)V oltage signal taken from the signal wire of Manifold Absolute Pressure sensor.This connection enables to measure the vacuum signal in the intake manifold so it is possible to make corrections of ignition point angle depending on engine load.Hint: In OSCAR-N SAS ECU we should connect it to the blue wire which goes to mapsensor [pin no. 3 in 4-pole AMP mapsensor plug].2.3. TPS signalSignal of Throttle position sensor or acceleration pedal sensor. Connecting that signal is required for proper calibration and detection of idle and cut-off conditions. TPS signal wire is the one on which voltage (regarding the ground ) changes its value fluently (eg. from 0 to 5V) when we are pressing on the accelerator pedal when vehicle's ignition key is on.2.4. Activation signalSignal which indicates when vehicle is running on gas and when on petrol. It is being used for activation of TAP to start advancing the original RPM signal when all cylinders has been switched to gas fuel.Hint. In case of use of OSCAR-N SAS system the best way of taking the activation signal is connecting to pink wire also used for disconnection of petrol fuel pump when system is on gas.Negative (“-”) signal appears on pink wire when OSCAR-N system is completely switched to gas and disappears in the moment when the system is switched back to petrol.We can also take positive (“+”) activation signal from +12V solenoid valve wire. In such case we should set proper type of gas activation signal (by “+”) in the EG Dynamic software. Gas controller should also be configured in such way to eliminate delays between moment of activating solenoid valves and changeover to gas.2.5. Crankshaft position sensor and camshaft position sensor signalsTo correct configuration we need to properly identify and connect the crankshaft position sensor and the camshaft position sensor(-s) (if present), are located. First, we set the sensor type: •if the connector have two pins, it is an inductive sensor type (resistance value for a typical inductive sensor is approximately 1 kOhm)•if connector has three-pins, it can be inductive sensor type(two pins sensor, the third pin ground. The resistance between the two pins of the sensor is approximately 1 kOhm, and the third pin from the ECU is connected to the ground)•if connector has three-pins, it can be digital sensor type(ground, power supply, signal).One pin from the ECU is connected to ground, the other is power "+12V from the ignition key", the third one is a signal cable).Attention: In controllers equipped with 3 digital channels (3D) it is not possible to configure the inductive sensor (the program automatically detects the type of device).Crankshaft position sensor signal:Main and most important signal to connect is the crankshaft position sensor signal. Camshaft position sensor signal don't have to be connected if it is not necessary to do so. This kind of necessity might happen when the original ECM of the car is report errors related with not synchronizing the camshaft position signal while advancing the signal from crankshaft position sensor. At first we should identify the type of sensor. Inductive sensor -usually it has pins which goes to two lines covered by a screen. Resistance measured between these two lines is around 1000 Ohm. If there are three pins, two of them are connected to signal lines and third one is connected with screen which is the ground signal of vehicle's ECU.Hint if possible we should find the place to cut into signal wires at where additional cover/screen insulation of signal wires is not present. First we should identify two signal wires, cut them and make serial connection by connecting proper pairs of wires from TAP device.There are four wires used to cut into vehicle's inductive signal wires: yellow and white -channel A, green and brown -channel B. We should start with cutting only one signal wire at a time (let's name it 'signal wire A') and connect first pair of inductive signal wires from TAP device:•yellow wire -should be connected with vehicle's inductive signal wire A input going from the inductive sensor•white wire -should be connected with vehicle's inductive signal wire A output going to the petrol ECU Then we proceed with cutting second signal wire (let's name it 'signal wire B') and connect remaining pair of inductive signal wires from TAP device:•green wire -should be connected with vehicle's inductive signal wire B input going from the inductive sensor•brown wire -should be connected with vehicle's inductive signal wire B output going to the petrol ECUAttention: If above connections will be made improperly we may be be not possible to start the vehicle.Camshaft position sensor:Digital sensor. Usually that kind of sensor have three lines signal, ground, power supply: +5V or +12V signal. We should cut only the signal wire and connect it serial to digital channel pair of wires.Hint: The original wire of signal input from digital sensor should be always connected to the color wire with black stripe (blue- black or yellow-black color). The adequate color wire without stripe should always be connected to that part of original vehicle's sensor signal wire which goes to the petrol ECU (blue or yellow color). Otherwise it might cause problem with engine work2.6. Diagnostic interface plugDiagnostic interface wire plug should be connected to EG Dynamic interface. It is possible to establish connection only if the TAP device is powered by +12V (the ignition key is on).2.7. Proper installation of TAP EG Dynamic ECUDuring the installation of TAP EG Dynamic ECU is suggested for the wire set to point downwards. It is also suggested that it should be placed in such a way to avoid the negative impact of high temperature and humidity. It is highly prohibited to spray ECU box with water jets or expose it to long lasting contact with water.3. Software description3.1. Right panel – actual value of system parameters:•Shifting – this value is informing if the impulses are being advanced or delayed (ON) or not (OFF) at the present moment.•Gas– this value is signaling on what fuel the car the car is actually running: on gas (ON) or petrol (OFF).•Angle [`] - angle value (in degrees) by which the current revolutions signal is being shifted.•RPM– rotary engine speed value.•TPS [%]– position of throttle position percentage (accelerator pedal).•MAP [kPa]– actual value of pressure in the intake manifold (engine load).•Inductive [Hz] - the current number of pulses per second for a signal from the inductive sensor.•Digital 1 [Hz] - The current number of pulses per second for a digital sensor signal no.•Digital 2 [Hz] - The current number of pulses per second for a digital sensor signal no.•Power supply [V]- power supply value. This value shouldn't be lower than 9V and not higher than 15V.If any parameter is marked by purple colour, it means that its value is out of allowed working range which determines when signal shifting can be done. Eg. the car is not in gas mode or the TPS signal is below minimum value which has been programmed to start shifting..If any parameter is marked by red colour, it means that its value is beyond the border value. Itprevents proper operation of TAP device. It might also mean that device does not recognize the shape of sensor signal wave. In such case it is necessary to physically check the signal connection and do another signal scanning from the software.3.2. Left panel – Settings bookmark•TPS Calibration - calibration of the minimum and maximum TPS input voltages for fully depressed and pressed accelerator pedal.•Enabling configuration - conditions that must be fulfilled so in the automatic mode the signal pulses shifting can be done.•Advanced◦Pressure sensor - selects the type MAP pressure sensor connected (in OSCAR-N SAS it's ABS400kPa).◦Signaling work on the gas- the choice of polarization of signal which enables shifting the signal pulses: If the TAP activation wire connection has been done topositive signal wire (like +12V solenoid valve wire) we need to choose “plus”. Ifwe've connected it to fuel pump disconnection signal (pink wire from OSCAR-NSAS which gives “ground” signal) we need to choose “minus”.◦TPS acceleration correction - the choice of TPS signal changes sensitivity. It's helpful in cases at which original ignition signal angle temporary increasessignificantly when accelerating. This allows to temporary increase the angle of signalshifting by extra velue for the rapid accelerations to compensate this signal change. Itworks only if RPM value is less than 1500 RPM.Attention: It is not reccomended to increase value of that parameter if it is notnecessary.◦Allowed retard – extends shift range for negative value. Default setting is OFF. Only for conversion from CNG to LPG use this option to retard ignition.•Inductive sensor, digital sensor 1, digital sensor 2◦Connections - selection of type of shaft where signal has been connected.◦Impulses per 1 revolution: number of pulses per revolution detected during a scan run (control value)◦Scan – starts automatic scanning the sensor signal wave. Should be carried out under stable conditions when the engine is running on idle. It is necessary to provide the actualvalue of engine rotary speed before starting scanning.In case that we've already scanned the wave of crankshaft sensor signal, and we need toget the shape of camshaft position signal wave we can select that option to allow thesignal to be read from that channel.Attention:It is very important to always start scanning from the crankshaft sensorsignal, and proceed to scanning of the camshaft sensors signals (if they have beenconnected)◦Preview - feature which enable us to check the shape of scanned sensor signal wave.3.3. Middle panel – MapsMap of the angle shifting regarding enginerotary speed.Point of the violet line indicates the currentsignal pulses shifting offset (in degrees).It is recommended to set a lower angle valueat higher rotary speeds.Multiplier Correction (eg. 1.0 is 100%, 0.6 is60% of original shifting offset) of the angleregarding the engine manifold absolutepressure(load).For heavy loads is recommended to set theadjustment below 1.0 to do not increase theengine knock value.Multiplier Correction (eg. 1.0 is 100%, 0.6 is60% of original shifting offset) of the angleregarding the TPS signal value.For idle conditions signal pulses shiftingshould be disabed , because it can lead toengines RPM waving in some type ofvehicles.We can do it by lowering themultiplier line on the map or in the Settingspanel.Allowed shortcuts and controls for map modification:•Left mouse button - move the points in the X and Y axis.•Right mouse button - move only points in Y axis.•Double click by left mouse button -add or remove point.•Arrow left, arrow right - selection of point.•Shift + arrow left, Shift + arrow righ t - selection of a group of points.•Ctrl + A – selection of all the points.•Arrow up, Arrow down - moving points in the Y-axis.•Home, End - moving points in the Y-axis with a higher speed•Ctrl + arrow up, Ctrl + down, Ctrl + left, Ctrl + right -moves points in the X and Y•Insert - adds another point•Delete - removes the selected point•Page Up, Page Down - moves the whole multiplier line in the Y-axis4. EG Dynamic TAP Calibration step-by-step.1.Establishing a connection– Turn on the ignition key to give +12V to the TAP device.Please select the right the serial port number from "Port" menu to establish a connection with diagnostic interface device.2.Calibrate TPS - while the engine is off, please make sure that ignition from the key is stillon and TAP device is being powered by +12V. In"TPS calibration", press"Set"button when the accelerator is fully depressed to remember that value as “Bottom TPS Threshold”.Then fully press the pedal all the way down and press "Set" button to store the maximum TPS voltage value as“Top TPS Threshold”.Check if changing the position of the acceleration pedal causes changing the current value of the TPS smoothly from 0 to 100%3.Selection of pressure sensor. -after selecting the appropriate sensor type when engine is off,and +12V from igniton on, the value of this parameter to indicate the MAP should be about 100 kPa. The default pressure sensor for OSCAR-N SAS is ABS400kPa.4.Selection of the activation of signal which indicates that vehicle is workng on gas-depending on where you connect the activation signal of TAP activation wire. If it has been connected to positive signal wire (eg. +12V solenoid valve wire) we need to choose “plus”.If we've connected it to fuel pump disconnection signal (eg. pink wire from OSCAR-N SAS which gives “ground” signal) we need to choose “minus”.5.Crankshaft sensor configuration - depending on the type of sensor and connection made toit (inductive or digital) we need to select proper type of that sensor in“Settings”panel.Then we should run a scan when the car is having working temperature and it is running on idle conditions..6.Camshaft sensors configuration–camshaft sensors should be connected only whennecessary (eg. when while shifting only the pulses from the crankshaft sensor, there is a check-engine associated with the camshaft sensor). The process of configuration is the same as in the case the crankshaft sensor configuration.7.Configuration of conditions of shifting the sensors pulses-In "Enabling configuration"panel we have to select the desired scopes of the TPS position, rotary speed, and select the “Shifting mode” to “automatic”. Mode “Always”which is permanently forcing TAP to shitf the signal pulses should be used onlyfor diagnostic purposes.8.Setting the map – We can leave default maps of sensor signal shifting or we can modify itaccording our requirements depending on the rotary speed, and the correction of the position of the TPS and MAP (load).。
Gardner-Denver (以下简称GD)集团公司始创于1859年，总部位于美国伊利诺斯周的昆西市，全球共有6500多名员工，年销售额超过20亿美元。
此外，GD集团公司已成为纽约证券交易所的一家上市公司，其缩写为GDI。
GD集团公司共有压缩机，风机，泵和流体输送四大部门，其中压缩机部在美国，芬兰，中国，英国，意大利等国家设有工厂办事处，在全球超过74个国家都有GD公司的销售代理商，数量超过500家。
目前，GD公司已成为全球最大的生产厂家之一。
另外作为一家全球著名的螺杆空压机制造商它还向全球多个空压机制造厂提供螺杆空气端(螺杆主机)，每年Gardner Denver有近20000套螺杆空气端提供给其全球OEM配套厂。
Gardner Denver一直秉承其传统，其产品线已有超过百年的历史，在全球已安装数以百万计的产品。
在其过往历史中， Gardner Denver 已作出众多战略并购，不断发展和扩展新市场。
许多被并购的公司在其特定市场中已建立的卓越的声望。
Gardner Denver 已在全球市场保留它们的股票，并将其纳入Gardner Denver 系列品牌中。
原始Gardner Denver品牌是最大的系列，产品包括风机、压缩机、高压水喷射系统、船用空气系统以及维修泵。
Champion品牌保留了于1919年成立的Champion Air Compressors的传统。
Champion 一直秉承其创新传统，为小型压缩机市场设计出第一款双级压缩机Champion 前后转动及螺杆式空气压缩机继续为世界提供高质量和价值。
Emco Wheaton品牌来自2004年的并购，向Gardner Denver的液体输送分部引入新产品线作为危险气体和液体散货储存及输送的领先供应商， Emco Wheaton可为海运、公路和铁路运输、存储以及航空行业制造鹤管、储油罐内配件以及燃料系统。
两大新近并收购的德国著名公司的合并形成了Elmo Rietschle品牌。
一种基于前馈定时的OQPSK解调方法张丽娜;陈敬乔【摘要】针对传统的偏移正交相移键控(OQPSK)解调方法中载波和定时同步进行、二者相互制约、调试难的问题,提出一种基于前馈定时的解调方法.采用频域非线性定时估计算法提取定时误差进行基于内插的定时恢复,利用FFT对数据进行载波频差估计,利用2倍数据的Costas环进行载波相位的恢复.该方法实现简单,避免调试中环套环时参数调试的困难.实验结果表明,解调信噪比恶化小于0.5 dB,可以用于指导工程实践.【期刊名称】《无线电工程》【年(卷),期】2018(048)006【总页数】4页(P468-471)【关键词】偏移正交相移键控;定时恢复;载波频差估计;载波相位恢复【作者】张丽娜;陈敬乔【作者单位】中国电子科技集团公司第五十四研究所, 河北石家庄050081;中国电子科技集团公司第五十四研究所, 河北石家庄050081【正文语种】中文【中图分类】TN911.30 引言偏移正交相移键控(Offset Quadrature Phase Shift Keying，OQPSK)是一种改进的正交相移键控(Quadrature Phase Shift Keying，QPSK)，与QPSK调制信号相比，OQPSK信号同相支路码元与正交支路码元在时间上偏移了半个符号周期。
OQPSK调制除了具有QPSK 调制的所有优点外，还消除了相邻符号间的180°相位跳变现象[1]，在带宽受限的通信系统中，OQPSK信号包络起伏小，经过非线性功率放大器后不产生明显的功率谱旁瓣增生效应。
因此，OQPSK调制所具有的恒包络特性、良好的频谱效率及功率效率使得它广泛地应用于卫星通信中。
典型的OQPSK解调[2]是常用的基于反馈定时的解调方法，采用Gardner算法[3]提取误差，调整AD时钟或者后端重采样[4-5]时钟，由于定时和载波恢复同时进行，二者相互制约，环路参数调试难度比较大，特别是低信噪比的情况下，实现比较困难，针对此问题，本文提出一种基于前馈定时的解调方法，将定时和载波恢复分开进行，解决了环套环调试困难的问题，并对解调流程和关键算法进行了详细分析，最后对仿真结果和工程实践进行了比较。
