消除笔记本的高频电流噪音

1、消除笔记本的高频电流噪音季光dummyshin.dum摘要：有些笔记本在使用中发出一种高频电流噪音。这种噪音随着硬盘的读写，用户对窗口界面中的滚动条的拉动发生变化，并在操作系统启动之后几乎始终存在，只有当用户播放音频文件时这种噪音会消失。本文利用这一特点针对Windows操作系统给出了消除噪音解决方案。本文设计了一个占用资源较少的Windows系统服务，在里面模拟音频文件的播放，从而将噪音消除。关键字：笔记本高频电流噪音Windows系统服务问题分析有些笔记本由于设计方面的问题，如果使用了USB设备或蓝牙模块，在运行中会发出一种高频电流噪音。例子包括Dell D610，Think R60e（在

2、使用电池的模式下）。这种噪音的来源并未得到官方的解释。但是有些厂商已经发布了修复这种噪音问题的BIOS补丁1。但是某些厂商并未正面解决这个问题2。有一种比较方便易行的方法可以把这种噪音消除：播放一个音频文件，然后按下暂停按钮。某些用户反映在运行一些游戏时也可以将噪音消除，其实也是利用了游戏背景音乐的作用。但是这种方法的缺点是需要手工操作，并且音乐播放器往往占用大量的内存。我们应该考虑用一种节省的方式实现它。设计与实现Windows提供了一组波形音频的编程接口。我们可以利用它们模拟播放器的暂停状态：/代码:模拟播放器的暂停状态HWAVEOUThWaveOut;/波形音频输出句柄BYTEmuteM

3、UTE_LENGTH;/静音符号串WAVEFORMATEXwaveformat=WAVE_FORMAT_PCM,1,SAMPLE_RATE,SAMPLE_RATE,1,8,0;/设定波形音频的格式WAVEHDRwaveHdr=0,MUTE_LENGTH,0,0,0,1,NULL,0;/音频数据信息头FillMemory(mute,MUTE_LENGTH,(BYTE)0x80);/用静音符号填充waveHdr.lpData=mute;/初始化信息头指针/打开音频设备waveOutOpen(&hWaveOut,WAVE_MAPPER,&waveformat,0,0,CALLBACK_FUNCTIO

4、N);/准备信息头waveOutPrepareHeader(hWaveOut,&waveHdr,sizeof(WAVEHDR);/播放静音符号waveOutWrite(hWaveOut,&waveHdr,sizeof(WAVEHDR);/暂停waveOutPause(hWaveOut);利用这段代码写一个win32程序，保证程序进程不会退出（可利用一个含有Sleep调用的死循环或弹出一个模态对话框实现），即可实现消除噪音的作用。然而这样做仍然不够完善。我们希望系统在启动的时候，无论有用户登录与否，都能够自动地调用它。为了解决这一问题，我们应当把它改造为Windows的系统服务。Windows系

5、统服务的编写需要服从一定的格式规范，请参阅相关文献3，本文不予详述。需要注意的是，如果编写为独立的Windows服务，仍然需要1,900K左右的内存；如果编写为寄存在svchost中的服务4，则可以把内存占用量大大降低，达到300400K。本文采用了后者。完整代码如下(我们把服务名取作DenoiseSvc31)：/*消电流噪声svchost版3.1*/#include#include#defineSLEEP_TIME10000#defineSERVICE_NAMEDenoiseSvc31 /服务名#defineMUTE_LENGTH128#defineSAMPLE_RATE11025SERVI

6、CE_STATUSServiceStatus;SERVICE_STATUS_HANDLEhStatus;voidInitService(void)HWAVEOUThWaveOut;BYTEmuteMUTE_LENGTH;WAVEFORMATEXwaveformat=WAVE_FORMAT_PCM,1,SAMPLE_RATE,SAMPLE_RATE,1,8,0;WAVEHDRwaveHdr=0,MUTE_LENGTH,0,0,0,1,NULL,0;FillMemory(mute,MUTE_LENGTH,(BYTE)0x80);waveHdr.lpData=mute;waveOutOpen(&hW

7、aveOut,WAVE_MAPPER,&waveformat,0,0,CALLBACK_FUNCTION);waveOutPrepareHeader(hWaveOut,&waveHdr,sizeof(WAVEHDR);waveOutWrite(hWaveOut,&waveHdr,sizeof(WAVEHDR);waveOutPause(hWaveOut);voidControlHandler(DWORDrequest)switch(request)caseSERVICE_CONTROL_STOP:caseSERVICE_CONTROL_SHUTDOWN:ServiceStatus.dwWin3

8、2ExitCode=0;ServiceStatus.dwCurrentState=SERVICE_STOPPED;SetServiceStatus(hStatus,&ServiceStatus);return;default:break;/ReportcurrentstatusSetServiceStatus(hStatus,&ServiceStatus);return;#pragmaargsused_declspec(dllexport)VOIDWINAPIServiceMain(DWORDdwArgc,LPTSTR*lpszArgv)ServiceStatus.dwServiceType=

9、SERVICE_WIN32_SHARE_PROCESS;ServiceStatus.dwCurrentState=SERVICE_START_PENDING;ServiceStatus.dwControlsAccepted=SERVICE_ACCEPT_STOP|SERVICE_ACCEPT_SHUTDOWN;ServiceStatus.dwWin32ExitCode=0;ServiceStatus.dwServiceSpecificExitCode=0;ServiceStatus.dwCheckPoint=0;ServiceStatus.dwWaitHint=0;hStatus=Regist

10、erServiceCtrlHandler(SERVICE_NAME,(LPHANDLER_FUNCTION)ControlHandler);if(hStatus=(SERVICE_STATUS_HANDLE)0)/RegisteringControlHandlerfailedreturn;/InitializeServiceInitService();/WereporttherunningstatustoSCM.ServiceStatus.dwCurrentState=SERVICE_RUNNING;SetServiceStatus(hStatus,&ServiceStatus);/Thewo

11、rkerloopofaservicewhile(ServiceStatus.dwCurrentState=SERVICE_RUNNING)Sleep(SLEEP_TIME);return;Svchost服务要求可执行文件必须为动态链接库。我们把它编译为denoise.dll并拷贝到%windir%system32目录下。剩下的任务就是把它安装到系统上。为系统添加一个服务需要修改注册表。对于Svchost服务，需要修改的地方包括：l HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionSvcHost：把服务添加到某个Svchost

12、组内。l HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServices：添加服务的主键及相关键值。代码如下：Windows Registry Editor Version 5.00HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesDenoiseSvc31Type=dword:00000020Start=dword:00000002ErrorControl=dword:00000001ImagePath=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00

13、,6f,00,6f,00, 74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,73, 00,76,00,63,00,68,00,6f,00,73,00,74,00,2e,00,65,00,78,00,65,00,20,00,2d,00, 6b,00,20,00,48,00,54,00,54,00,50,00,46,00,69,00,6c,00,74,00,65,00,72,00,00, 00DisplayName=DenoiseSvc31DependOnService=hex(7):4c,00,61,

14、00,6e,00,6d,00,61,00,6e,00,57,00,6f,00,72,00, 6b,00,73,00,74,00,61,00,74,00,69,00,6f,00,6e,00,00,00,00,00DependOnGroup=hex(7):00,00ObjectName=NT AUTHORITYLocalServiceDescription=消除笔记本的高频电流噪音HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesDenoiseSvc31Enum0=RootLEGACY_ALERTER0000Count=dword:00000001N

15、extInstance=dword:00000001HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesDenoiseSvc31ParametersAlertNames=hex(7):00,00ServiceDll=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f, 00,74,00,25,00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00, 64,00,65,00,6e,00,6f,00,69,0

16、0,73,00,65,00,2e,00,64,00,6c,00,6c,00,00,00HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesDenoiseSvc31SecuritySecurity=hex:01,00,14,80,90,00,00,00,9c,00,00,00,14,00,00,00,30,00,00,00,02, 00,1c,00,01,00,00,00,02,80,14,00,ff,01,0f,00,01,01,00,00,00,00,00,01,00,00, 00,00,02,00,60,00,04,00,00,00,00,00

17、,14,00,fd,01,02,00,01,01,00,00,00,00,00, 05,12,00,00,00,00,00,18,00,ff,01,0f,00,01,02,00,00,00,00,00,05,20,00,00,00, 20,02,00,00,00,00,14,00,8d,01,02,00,01,01,00,00,00,00,00,05,0b,00,00,00,00, 00,18,00,fd,01,02,00,01,02,00,00,00,00,00,05,20,00,00,00,23,02,00,00,01,01, 00,00,00,00,00,05,12,00,00,00,0

18、1,01,00,00,00,00,00,05,12,00,00,00HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionSvcHostHTTPFilter=hex(7):48,00,54,00,54,00,50,00,46,00,69,00,6c,00,74,00,65,00,72, 00,00,00,44,00,65,00,6e,00,6f,00,69,00,73,00,65,00,53,00,76,00,63,00,33,00, 31,00,00,00,00,00把它保存在denoise.reg中双击运行，然后重启机器，噪音问题就解决了