Design And Research Of Morse Auto-coding System Based On PIC16F877 Single-Chip

Morse code is a coding method, which is used widely. The design of auto-coding system for Morse code beat by handcraft is introduced in this paper.Firstly, the origin of Morse code and the auto-coding system are introduced, and the possibility of the system is analyzed in this paper. In the second thesis of this paper, the system hardware is discussed in detail. The hardware circuit's primary function is transforming the received analog signals to the pulse signal. The hardware parts include the amplitude decoding and the frequency decoding, which can be selected based on the situation. Limitting and magnifing amplitude circuit decoding display circuit single-chip interface circuit and serial communication circuit are the common parts of the amplitude decoding and the frequency decoding. In addition, the amplitude decoding includes the voltage comparing circuit multitude feedback band-pass filter circuit demodulation circuit regulating circuit;and the frequency decoding includes the NE576 decoding circuit.The self-adapting coding arithmetic of the Morse code beat by handcraft is introduced primarily; the software design is the emphasis in this paper. The coding arithmetic and the program the software design based on PIC16F877 single-chip are described in detail. The key of the coding is the real-time change of the code speed, calculating dynamically two kinds of basal code and the three kinds of value of gap signal. The system coding idea is discussed in this part. To realize the saving and computing of the time width for effective signals, the high and low impulse width time is obtained, and the interferential impulse signals are removed by using break-catching manner. A set of signals is managed in the main program, the code-speed is computed timely and the sort coefficient of all kinds of signals is confirmed, so the Morse code's information can be reverted by using code table. According to this idea, C language for the single-chip is adopted, and the main design flow charts are presented in this paper.The problems appearing in the course of debugging of the amplitude decoding and the frequency decoding are analyzed and concluded, respectively. At the same time, the problems about the software arithmetic are analyzed by chart, and the resolved methods are presented.The last part is conclusion and expectation of this thesis.