生成2KHz和8KHz的混合信号，使该信号通过上述滤波器，观察滤波前后的波形变化和频谱分布情况。-2KHz and 8KHz generation mixed-signal, so that the signal through the above-mentioned filter, filter before and after observation of the waveform and spectrum distribution of the changes.
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001484s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.092516s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001433s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001739s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001166s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003439s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001286s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.007645s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.019381s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001208s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 158503 [ RunTime:0.018294s ]
