通过VHDL程序设计一个4人参加的智力竞赛抢答计时器，当有某一参赛者首先按下抢答开关时，相应显示灯亮并伴有声响，此时抢答器不再接受其他输入信号。

电路具有回答问题时间控制功能。要求回答问题时间小于等于100s(显示为0~99)，时间显示采用倒计时方式。当达到限定时间时，发出声响以示警告。

-VHDL programming by a 4 quiz participants answer in timer, when a participant first press the answer in the switch, the corresponding display lights and accompanied by sound, then Responder no longer accept other input signals. Time control circuit has functions to answer questions. Required to answer questions in less than equal to 100s (shown as 0 to 99), with the countdown time display mode. When the time limit is reached, audible as a warning.