lock-in circuit

例句：

1. 1.The lock-in circuit was designed to prevent unauthorized access.
   锁定电路被设计来防止未经授权的访问。
2. 2. The engineer used a lock-in circuit to test the device's functionality.
   工程师使用锁定电路来测试设备的功能。
3. 3. The lock-in circuit is essential for maintaining secure communication between two devices.
   锁定电路对于保持两个设备之间的安全通信至关重要。