| 摘要 |
The present invention relates to a speaker preset circuit which includes: a preset switch unit for generating a preset signal to determine a preset state of a speaker; a trigger switch unit for generating a trigger signal to control a speaker output according to a switch operation; a reset unit for generating a reset signal; a first logic circuit unit for outputting a result value 1 obtained by logically operating an inverting value of the preset signal and the reset signal and a result value 2 obtained by logically operating the preset signal and the reset signal; and a second logic circuit unit for receiving the result values 1 and 2 from the first logic circuit unit as stable values and receiving the trigger signal as a control pulse to output a signal for controlling an output of the speaker. Thus, the preset function, which is capable of replacing a backup function of a speaker selector including one state switch such as a tact switch as a selector switch, may be implemented at low costs without using a very expensive IC device such as a microprocessor. |
