消除筆記本的高頻電流噪音

1、消除筆記本的高頻電流噪音季光dummyshin.dum摘要：有些筆記本在使用中發(fā)出一種高頻電流噪音。這種噪音隨著硬盤的讀寫，用戶對窗口界面中的滾動條的拉動發(fā)生變化，并在操作系統(tǒng)啟動之后幾乎始終存在，只有當用戶播放音頻文件時這種噪音會消失。本文利用這一特點針對Windows操作系統(tǒng)給出了消除噪音解決方案。本文設計了一個占用資源較少的Windows系統(tǒng)服務，在里面模擬音頻文件的播放，從而將噪音消除。關鍵字：筆記本高頻電流噪音Windows系統(tǒng)服務問題分析有些筆記本由于設計方面的問題，如果使用了USB設備或藍牙模塊，在運行中會發(fā)出一種高頻電流噪音。例子包括Dell D610，Think R60e（在

2、使用電池的模式下）。這種噪音的來源并未得到官方的解釋。但是有些廠商已經發(fā)布了修復這種噪音問題的BIOS補丁1。但是某些廠商并未正面解決這個問題2。有一種比較方便易行的方法可以把這種噪音消除：播放一個音頻文件，然后按下暫停按鈕。某些用戶反映在運行一些游戲時也可以將噪音消除，其實也是利用了游戲背景音樂的作用。但是這種方法的缺點是需要手工操作，并且音樂播放器往往占用大量的內存。我們應該考慮用一種節(jié)省的方式實現(xiàn)它。設計與實現(xiàn)Windows提供了一組波形音頻的編程接口。我們可以利用它們模擬播放器的暫停狀態(tài)：/代碼:模擬播放器的暫停狀態(tài)HWAVEOUThWaveOut;/波形音頻輸出句柄BYTEmuteM

3、UTE_LENGTH;/靜音符號串WAVEFORMATEXwaveformat=WAVE_FORMAT_PCM,1,SAMPLE_RATE,SAMPLE_RATE,1,8,0;/設定波形音頻的格式WAVEHDRwaveHdr=0,MUTE_LENGTH,0,0,0,1,NULL,0;/音頻數(shù)據(jù)信息頭FillMemory(mute,MUTE_LENGTH,(BYTE)0x80);/用靜音符號填充waveHdr.lpData=mute;/初始化信息頭指針/打開音頻設備waveOutOpen(&hWaveOut,WAVE_MAPPER,&waveformat,0,0,CALLBACK_FUNCTIO

4、N);/準備信息頭waveOutPrepareHeader(hWaveOut,&waveHdr,sizeof(WAVEHDR);/播放靜音符號waveOutWrite(hWaveOut,&waveHdr,sizeof(WAVEHDR);/暫停waveOutPause(hWaveOut);利用這段代碼寫一個win32程序，保證程序進程不會退出（可利用一個含有Sleep調用的死循環(huán)或彈出一個模態(tài)對話框實現(xiàn)），即可實現(xiàn)消除噪音的作用。然而這樣做仍然不夠完善。我們希望系統(tǒng)在啟動的時候，無論有用戶登錄與否，都能夠自動地調用它。為了解決這一問題，我們應當把它改造為Windows的系統(tǒng)服務。Windows系

5、統(tǒng)服務的編寫需要服從一定的格式規(guī)范，請參閱相關文獻3，本文不予詳述。需要注意的是，如果編寫為獨立的Windows服務，仍然需要1,900K左右的內存；如果編寫為寄存在svchost中的服務4，則可以把內存占用量大大降低，達到300400K。本文采用了后者。完整代碼如下(我們把服務名取作DenoiseSvc31)：/*消電流噪聲svchost版3.1*/#include#include#defineSLEEP_TIME10000#defineSERVICE_NAMEDenoiseSvc31 /服務名#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服務要求可執(zhí)行文件必須為動態(tài)鏈接庫。我們把它編譯為denoise.dll并拷貝到%windir%system32目錄下。剩下的任務就是把它安裝到系統(tǒng)上。為系統(tǒng)添加一個服務需要修改注冊表。對于Svchost服務，需要修改的地方包括：l HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionSvcHost：把服務添加到某個Svchost

12、組內。l HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServices：添加服務的主鍵及相關鍵值。代碼如下：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=消除筆記本的高頻電流噪音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中雙擊運行，然后重啟機器，噪音問題就解決了