針對目前使用的RS232接口數字化B超鍵盤存在PC主機啟動時不能設置BIOS，提出一種PS2鍵盤的設計方法?；赪78E052D單片機，采用8通道串行A/D轉換器設計了8個TGC電位器信息采集電路，電位器位置信息以鍵盤掃描碼序列形式發送，正交編碼器信號通過XC9536XL轉換為單片機可接收的中斷信號，軟件接收到中斷信息后等效處理成按鍵。結果表明，在滿足開機可設置BIOS同時，又可實現超聲特有功能，不需要專門設計驅動程序，接口簡單，成本低。
Abstract: Aiming at the problem of the digital ultrasonic diagnostic imaging system keyboard with RS232 interface currently used couldn?蒺t set the BIOS when the PC boot， this paper proposed a design method of PS2 keyboards. Based on W78E052D microcontroller，designed eight TGC potentiometers information acquisition circuit with 8-channel serial A/D converter， potentiometer position information sent out with keyboard scan code sequentially.The control circuit based on XC9536 CPLD is used for converting the mechanical actions of the encoders into the signals that can be identified by the MCU， software received interrupt information and equivalently treatmented as key. The results show that the BIOS can be set to meet the boot， ultrasound specific functionality can be achieved at the same time， it does not require specially designed driver，the interface is simple and low cost.
Rotating shafts experience a an elliptical motion called whirl. It is important to decompose this motion into a forward and backward whil orbits. The current function makes use of two sensors to generate a bi-directional spectrogram. The method can be extended to any time-frequency distribution
％
％ compute the forward/backward Campbell/specgtrogram
％
％ INPUT:
％ y (n x 2) each column is measured from a different sensor
％ ///////
％ __
％ |s1| y(:,1)
％ |__|
％ __
％ / \ ________|/
％ | | | s2 |/ y(:,2)
％ \____/ --------|/
％
％ Fs Sampling frequnecy
％
％ OUTPUT:
％ B spectrogram/Campbel diagram
％ x x-axis coordinate vector (time or Speed)
％ y y-axis coordinate vector (frequency [Hz])
Verilog HDL: Magnitude
For a vector (a,b), the magnitude representation is the following:
A common approach to implementing these arithmetic functions is to use the Coordinate Rotation Digital Computer (CORDIC) algorithm. The CORDIC algorithm calculates the trigonometric functions of sine, cosine, magnitude, and phase using an iterative process. It is made up of a series of micro-rotations of the vector by a set of predetermined constants, which are powers of two. Using binary arithmetic, this algorithm essentially replaces multipliers with shift and add operations. In a Stratix™ device, it is possible to calculate some of these arithmetic functions directly, without having to implement the CORDIC algorithm.
實現最優二叉樹的構造；在此基礎上完成哈夫曼編碼器與譯碼器。 假設報文中只會出現如下表所示的字符：
字符 A B C D E F G H I J K L M N
頻度 186 64 13 22 32 103 21 15 47 57 1 5 32 20 57
字符 O P Q R S T U V W X Y Z ， ．
頻度 63 15 1 48 51 80 23 8 18 1 16 1 6 2
要求完成的系統應具備如下的功能：
1．初始化。從終端（文件）讀入字符集的數據信息，。建立哈夫曼樹。
2．編碼：利用已建好的哈夫曼樹對明文文件進行編碼，并存入目標文件（哈夫曼碼文件）。
3．譯碼：利用已建好的哈夫曼樹對目標文件（哈夫曼碼文件）進行編碼，并存入指定的明文文件。
4．輸出哈夫曼編碼文件：輸出每一個字符的哈夫曼編碼。
