在理論分析循環碼編碼和譯碼基本原理的基礎上,提出了基于單片機系統的(24,16)循環碼軟件實現編碼、譯碼的方案。仿真結果表明(24,16)循環碼能有效地克服來自通訊信道的干擾,保證數據通信的可靠及系統的穩定,使誤碼率大幅度降低。本論文對(24,16)循環碼的研究結果表明,可以有效地降低錯誤概率和提高系統的吞吐量,實現糾錯僅需要在接收端增加有限的存儲空間和計算復雜度,具有一定的實用價值。
Abstract:
Based on analyzing the theory of encoding and decoding of cyclic code, this paper showed the schemes of encoding and decoding of(24,16)cyclic code by the software and based on microcontroller. Simulation results show that using (24,16) cyclic codes can effectively overcome the interference from communication channel, ensure the reliability and stability of data communication systems, and reduce the bit error rate greatly. The results of this paper show that by using the (24,16) cyclic code, the error rate can be reduced and the system throughput can be improved. Meanwhile, the system only needs to enlarge limited storage space and computation the complexity at the receiving end to realize error correction. Thus the (24,16) cyclic code has a practical value.
針對煤礦井下調度及緊急救援系統的需求,以DTMF編解碼模塊為核心,設計了具有自動撥號功能的新型電話系統。該系統利用MT8880對DTMF信號的編解碼功能實現一鍵撥號和遠程設置,通過檢測振鈴和忙音信號,完成自動摘機和掛機過程,配合AGC等外圍電路達到話音清晰流暢的效果。
Abstract:
To meet the demand for mine scheduling and emergency rescue system, with using DTMF signal codec as the core, a new telephone system was designed with automatic dialing function. In the system, the DTMF signal encoding and decoding function of MT8880 was used to achieve one-touch dialing and remote setting. The circuit detects the ringing and busy signal, and then completes automatic off-hook and hangup. With AGC(Automatic Gain Control) and other peripheral circuits, the voice was regulated to a clear and smooth effect.
RSA算法 :首先, 找出三個數, p, q, r, 其中 p, q 是兩個相異的質數, r 是與 (p-1)(q-1) 互質的數...... p, q, r 這三個數便是 person_key,接著, 找出 m, 使得 r^m == 1 mod (p-1)(q-1)..... 這個 m 一定存在, 因為 r 與 (p-1)(q-1) 互質, 用輾轉相除法就可以得到了..... 再來, 計算 n = pq....... m, n 這兩個數便是 public_key ,編碼過程是, 若資料為 a, 將其看成是一個大整數, 假設 a < n.... 如果 a >= n 的話, 就將 a 表成 s 進位 (s
數字運算,判斷一個數是否接近素數
A Niven number is a number such that the sum of its digits divides itself. For example, 111 is a Niven number because the sum of its digits is 3, which divides 111. We can also specify a number in another base b, and a number in base b is a Niven number if the sum of its digits divides its value.
Given b (2 <= b <= 10) and a number in base b, determine whether it is a Niven number or not.
Input
Each line of input contains the base b, followed by a string of digits representing a positive integer in that base. There are no leading zeroes. The input is terminated by a line consisting of 0 alone.
Output
For each case, print "yes" on a line if the given number is a Niven number, and "no" otherwise.
Sample Input
10 111
2 110
10 123
6 1000
8 2314
0
Sample Output
yes
yes
no
yes
no
The government of a small but important country has decided that the alphabet needs to be streamlined and reordered. Uppercase letters will be eliminated. They will issue a royal decree in the form of a String of B and A characters. The first character in the decree specifies whether a must come ( B )Before b in the new alphabet or ( A )After b . The second character determines the relative placement of b and c , etc. So, for example, "BAA" means that a must come Before b , b must come After c , and c must come After d .
Any letters beyond these requirements are to be excluded, so if the decree specifies k comparisons then the new alphabet will contain the first k+1 lowercase letters of the current alphabet.
Create a class Alphabet that contains the method choices that takes the decree as input and returns the number of possible new alphabets that conform to the decree. If more than 1,000,000,000 are possible, return -1.
Definition