基于51單片機的多功能門鈴的設(shè)計外文資料翻譯-閱讀頁
2024-12-14 03:43本頁面
【正文】 ength, frame synchronization code can be arbitrary choice, the general choice 0xAA, 0x55, such as 0 1 uniform Distribution of data, and in order to improve reliability, often the choice of multibyte frame synchronization code, such as 0xAA 0xBB (2byte frame synchronization code). To establish stable munication, a standard wireless data transmission frame should include at least the following parts: (1) Jumping code: in the receiving establishment phase, providing reception threshold level, its length and hardware relevant data, wireless doorbell system visualization Talkback used in the x99 is 0. (2) redundant code: According to experience, usually adopts a 0xff or 0xff, 0x66 results were relatively good, and the establishment of munication to correct errors arising from the phaseoutofstep serial receiver, in the slow speed (19200 bps), the two often use Lredundant code is not adopted in the design. (3)Synchronous Code: used for frame synchronization, data transfer and use of relatively lowbitrate code word, and in order to improve reliability, and a 2byte or 2 bytes above synchronous code words such as 0xaa 0xbb. Visual Round wireless doorbell system is used in the 0xCCCCCC. (4)Data: users want to transfer data to improve the reliability of munications, the proposed Manchester encoding the data or using DPCM send, and data validation. Manchester encoding or used in the DPCM transmitted, the length of the data generally should not exceed 256 bytes。 If the first three bytes or 0xCC from entering the state 2 3 state into synchronous state, or to return to state 0 which DPLL is a bit synchronization. As voice signals are relatively weak in general, according to M u/A code of law, may be even longer, 1, so that the receiver can not extract the correct information in sync, so we carried out a simple voice and data handling, even if 1 is greater than the number eight, an eighth reverse, namely, 1 to 0. As one of the quantitative data sampling points last a minimum weights, this will not deal with the impact of. Last: Concluding remarks Based on the visualspeaking wireless doorbell system, and its twoway voice munications for the design and realization, it is has been tested and empty distance of 60 m, 30 m to obstructions, clear voice L test results show that the design of a performance stable and reliable, voice clear, simple design, and other features, the value of L practical course of the programme in this paper on the properties have yet to be improved, then we have to do the work is the image of realtime digital information transmission, thus achieving alldigital wireless Visualization Round doorbell system.
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