Radio frequency (RF) can be a complex subject to navigate, but it does not have to be. If you are just getting started with radios or maybe you cannot find that old reference book about antenna aperture, this guide can help. It is intended to provide a basic understanding of RF technology, as well act as a quick reference for those who “know their stuff” but may be looking to brush up on that one niche term that they never quite understood. This document is also a useful reference for Maxim’s products and data sheets, an index to deeper analysis found in our application notes, and a general reference for all things RF.
標(biāo)簽： 無線技術(shù)
上傳時(shí)間： 2013-10-08
上傳用戶：kinochen
在研究傳統(tǒng)家用燃?xì)鈭?bào)警器的基礎(chǔ)上，以ZigBee協(xié)議為平臺(tái)，構(gòu)建mesh網(wǎng)狀網(wǎng)絡(luò)實(shí)現(xiàn)網(wǎng)絡(luò)化的智能語音報(bào)警系統(tǒng)。由于傳感器本身的溫度和實(shí)際環(huán)境溫度的影響，傳感器標(biāo)定后采用軟件補(bǔ)償方法。為了減少系統(tǒng)費(fèi)用，前端節(jié)點(diǎn)采用半功能節(jié)點(diǎn)設(shè)備，路由器和協(xié)調(diào)器采用全功能節(jié)點(diǎn)設(shè)備，構(gòu)建mesh網(wǎng)絡(luò)所形成的家庭內(nèi)部報(bào)警系統(tǒng)，通過通用的電話接口連接到外部的公用電話網(wǎng)絡(luò)，啟動(dòng)語音模塊進(jìn)行報(bào)警。實(shí)驗(yàn)結(jié)果表明，在2.4 GHz頻率下傳輸，有墻等障礙物的情況下，節(jié)點(diǎn)的傳輸距離大約為35 m，能夠滿足家庭需要，且系統(tǒng)工作穩(wěn)定，但在功耗方面仍需進(jìn)一步改善。 Abstract: On the basis of studying traditional household gas alarm system, this paper proposed the platform for the ZigBee protocol，and constructed mesh network to achieve network-based intelligent voice alarm system. Because of the sensor temperature and the actual environment temperature, this system design used software compensation after calibrating sensor. In order to reduce system cost, semi-functional node devices were used as front-end node, however, full-function devices were used as routers and coordinator，constructed alarm system within the family by building mesh network，connected to the external public telephone network through the common telephone interface, started the voice alarm module. The results indicate that nodes transmit about 35m in the distance in case of walls and other obstacles by 2.4GHz frequency transmission, this is able to meet family needs and work steadily, but still needs further improvement in power consumption.
標(biāo)簽： ZigBee 無線智能 家 報(bào)警系統(tǒng)
上傳時(shí)間： 2013-10-30
上傳用戶：swaylong
The LTC®3207/LTC3207-1 is a 600mA LED/Camera driverwhich illuminates 12 Universal LEDs (ULEDs) and onecamera fl ash LED. The ULEDs are considered universalbecause they may be individually turned on or off, setin general purpose output (GPO) mode, set to blink at aselected on-time and period, or gradate on and off at aselected gradation rate. This device also has an externalenable (ENU) pin that may be used to blink, gradate, orturn on/off the LEDs without using the I2C bus. This may beuseful if the microprocessor is in sleep or standby mode. Ifused properly, these features may save valuable memoryspace, programming time, and reduce the I2C traffi c.
上傳時(shí)間： 2014-01-04
上傳用戶：LANCE
This errata sheet describes both the known functional problems and anydeviations from the electrical specifications known at the release date ofthis document.Each deviation is assigned a number and its history is tracked in a table atthe end of the document.
上傳時(shí)間： 2013-11-22
上傳用戶：liangliang123
On the LPC13xx, programming, erasure and re-programming of the on-chip flash can be performed using In-System Programming (ISP) via the UART serial port, and also, can be performed using In-Application Programming (IAP) calls directed by the end-user code. For In-System Programming (ISP) via the UART serial port, the ISP command handler (resides in the bootloader) allows erasure of one or more sector (s) of the on-chip flash memory.
標(biāo)簽： 1300 LPC 勘誤 數(shù)據(jù)手冊(cè)
上傳時(shí)間： 2013-12-13
上傳用戶：lmq0059
This errata sheet describes both the known functional problems and anydeviations from the electrical specifications known at the release date ofthis document.Each deviation is assigned a number and its history is tracked in a table atthe end of the document.
上傳時(shí)間： 2014-12-31
上傳用戶：thuyenvinh
1 任務(wù) 設(shè)計(jì)一個(gè)文本編輯器。 2 基本要求 1 如圖所示，設(shè)計(jì)一個(gè)有菜單欄的編輯窗口，在該窗口可以實(shí)現(xiàn)文本的輸入，利用DEL鍵、BackSpace鍵、Home鍵、End鍵、上下左右光標(biāo)鍵，實(shí)現(xiàn)對(duì)輸入文本的全屏幕編輯。 2 實(shí)現(xiàn)文件的新建、打開、保存、另存為與退出等功能。 包含 設(shè)計(jì)思路、技術(shù)報(bào)告、和不同階段的設(shè)計(jì)源代碼 擴(kuò)展要求 1 要求使用彩色組和背景顏色來設(shè)計(jì)界面顏色。 2 模擬一些著名編輯器（如Source Insight）的其它功能，如比較詳細(xì)的幫助功能，對(duì)特定的命令或保留字（如C語言或匯編語言）能顯示不同的醒目顏色。 3 自己參考其它編輯器進(jìn)行發(fā)揮。
上傳時(shí)間： 2013-11-03
上傳用戶：lhc9102
10種軟件濾波方法的示例程序 假定從8位AD中讀取數(shù)據(jù)（如果是更高位的AD可定義數(shù)據(jù)類型為int),子程序?yàn)間et_ad(); 1、限副濾波 /* A值可根據(jù)實(shí)際情況調(diào)整 value為有效值，new_value為當(dāng)前采樣值 濾波程序返回有效的實(shí)際值 */ #define A 10 char value; char filter() { char new_value; new_value = get_ad(); if ( ( new_value - value > A ) || ( value - new_value > A ) return value; return new_value; }
上傳時(shí)間： 2013-11-11
上傳用戶：gxf2016
This example provides a description of how to use the USART with hardware flowcontrol and communicate with the Hyperterminal.First, the USART2 sends the TxBuffer to the hyperterminal and still waiting fora string from the hyperterminal that you must enter which must end by '\r'character (keypad ENTER button). Each byte received is retransmitted to theHyperterminal. The string that you have entered is stored in the RxBuffer array. The receivebuffer have a RxBufferSize bytes as maximum. The USART2 is configured as follow: - BaudRate = 115200 baud - Word Length = 8 Bits - One Stop Bit - No parity - Hardware flow control enabled (RTS and CTS signals) - Receive and transmit enabled - USART Clock disabled - USART CPOL: Clock is active low - USART CPHA: Data is captured on the second edge - USART LastBit: The clock pulse of the last data bit is not output to the SCLK pin
上傳時(shí)間： 2013-10-31
上傳用戶：yy_cn
This example shows how to update at regulate period the WWDG counter using theEarly Wakeup interrupt (EWI). The WWDG timeout is set to 262ms, refresh window set to 41h and the EWI isenabled. When the WWDG counter reaches 40h the EWI is generated and in the WWDGISR the counter is refreshed to prevent a WWDG reset and led connected to PC.07is toggled.The EXTI line9 is connected to PB.09 pin and configured to generate an interrupton falling edge.In the NVIC, EXTI line9 to 5 interrupt vector is enabled with priority equal to 0and the WWDG interrupt vector is enabled with priority equal to 1 (EXTI IT > WWDG IT). The EXTI Line9 will be used to simulate a software failure: once the EXTI line9event occurs (by pressing Key push-button on EVAL board) the correspondent interruptis served, in the ISR the led connected to PC.07 is turned off and the EXTI line9pending bit is not cleared. So the CPU will execute indefinitely EXTI line9 ISR andthe WWDG ISR will never be entered(WWDG counter not updated). As result, when theWWDG counter falls to 3Fh the WWDG reset occurs.If the EXTI line9 event don抰 occurs the WWDG counter is indefinitely refreshed inthe WWDG ISR which prevent from WWDG reset. If the WWDG reset is generated, after resuming from reset a led connected to PC.06is turned on. In this example the system is clocked by the HSE(8MHz).
上傳時(shí)間： 2013-11-11
上傳用戶：gundamwzc
蟲蟲下載站版權(quán)所有 京ICP備2021023401號(hào)-1
