fix_channel ka频段，卫星信道建模仿真。-fix_channel,satellite channel fix.

convert infix expression to post fix expression and evaluate post fix expression

HI-TECH PIC C Compiler Version 8.05PL2 + unlimited fix

Syntax Analyzer: this tool with nice GUI can analyze the simple C++ code for syntax errors! It will also tell you the line of syntax error! You could type the code or open a text file with code, and it is also possible to save a file with code.