04 2011 档案

 
线性系统, 卷积, 线性时不变
摘要:线性系统 对某个特定系统,输入x1(t)产生输出y1(t)即:x1(t)—>y1(t),而对另一个输入x2(t)产生输出y2(t)即:x2(t)—>y2(t)。 这个系统是线性的,当且仅当它满足如下条件:x1(t)+x2(t)—>y1(t)+y2(t)。 卷积 卷积的物理意义: 在生活当中有很多现象都体现了卷积的含义,比如古人钻木取火就是一个很形象的例子。当我们用一根木头与另一根木头接触并钻一下,由于摩擦产生热,在两根木头接触的地方就会发热,但是很明显,就只钻一下,木头是不可能燃起来的,而且随着时间变长,那一点由摩擦产生的热量会一点一点消失掉。妙果我们加快钻的频率,也就是在之 阅读全文
posted @ 2011-04-17 17:39 做个不善的人 阅读(4503) 评论(1) 推荐(0)
Time/Timer in Linux vs. Windows
摘要:数据类型time_t: Calendar time#include <time.h>time_t time(time_t *t);[obsoleted by gettimeofday]获取自从1970.1.1 00:00:00到现在为止的时间,以秒为单位。#include <sys/timeb.h>int ftime(struct timeb *tp);[Obsoleted]#include <time.h>int clock_getres(clockid_t clk_id, struct timespec *res);int clock_gettime(c 阅读全文
posted @ 2011-04-01 17:09 做个不善的人 阅读(2456) 评论(0) 推荐(0)
Dynamic-Link Libraries on Windows vs. Linux
摘要:A DLL can define two kinds of functions: exported and internal. The exported functions are intended to be called by other modules, as well as from within the DLL where they are defined. Internal functions are typically intended to be called only from within the DLL where they are defined. Although a 阅读全文
posted @ 2011-04-01 15:22 做个不善的人 阅读(229) 评论(0) 推荐(0)
Dynamic Linking Loader in Linux
摘要:The four functions dlopen(), dlsym(), dlclose(), dlerror() implement the interface to the dynamic linking loader.#include <dlfcn.h>void *dlopen(const char *filename, int flag);char *dlerror(void);void *dlsym(void *handle, const char *symbol);int dlclose(void *handle);dlerrordlerror() 返回一个适合程序员 阅读全文
posted @ 2011-04-01 14:56 做个不善的人 阅读(1458) 评论(0) 推荐(0)