按航模通道控制PPM信号要求做的一个测试仪，可测试舵机和电调无刷电机等。输出信号周期为20mS，高电平变化量为1mS~2mS。通过按键实现手动测试、自动回中、自动测试功能。（刚开始对航模感兴趣，初学编程所做的小玩意儿）(A testing instrument for controlling the PPM signal according to the channel channel can be used to test the rudder and electric brushless m