1）能够输出锯齿波，三角波，正弦波，脉冲波.
（2）能根据键盘命令进行波形之间的切换.
（3）能对输出的波形频率进行调节。
-1) can output sawtooth, triangle wave, sine wave, pulse wave. (2) according to the keyboard command to switch between waveforms. (3) can adjust the output waveform frequency.
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001537s ]
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:0.100970s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001037s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001151s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001013s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003057s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.000844s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003680s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.015608s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001041s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 212939 [ RunTime:0.023790s ]
