某温度信号如图（a）所示，经温度传感器测量后得到图（b）波形，经采样后得到图（c）波形，再经保持器得到图（d）波形，那么（　　）。<br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818676_0.png"><br/> 图（a）<br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818676_0_1.png"><br/> 图（b）<br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818676_0_2.png"><br/> 图（c）<br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23818676_0_3.png"><br/> 图（d）<br/>