应答器

What is a transponder?

应答器是无线的通信，监视或控制设备可以自动响应传入信号。该术语是transmitter和responder。

Transponders are typically used for detecting, identifying and locating objects, but they can also be used in other technologies, such as in satellites to relay communications signals. Transponders are commonly found in both civilian and military aircraft and in objects, such as car keys.

发件人是用什么？

发频器与以下技术一起使用：

• aircraft identification;
• communications satellites;
• 车钥匙；
• 光学通信；
• 声纳
• 电子收费系统；
• lap timing andtire identificationfor motor sports; and
• magnetic labels on credit cards.

How do transponders work?

Transponders operate using radio频率并响应无线监控，通信和控制设备信号。

When sent a signal -- also called an询问者- 应答器通过返回识别信号来做出响应。响应中包含的信息取决于应答器的类型，但可以包括位置和识别代码。应答器会自动以预定的频率发回无线电信号。要同时接收并发送信号，必须以不同的频率设置接收和发送信号。

空中交通管制员可以发送询问器信号并接收有关飞机的识别信息。这使控制塔可以跟踪周围空域中的飞机，并提供其他信息，以帮助飞行员保持与其他飞机的足够距离。

飞机中的特征器可以归类为模式A，C或S，并通过以下方式工作：

• 模式a应答器s transmit an identifying transponder code -- also called asquawkcode -- to air traffic control.
• 模式c传输将识别码和飞机高度传输到空中交通管制。
• 模式s应答器s transmit the identifying code, aircraft altitude, registration information and speed to air traffic control and other in-range aircraft with Mode S transponders.

带有模式的飞机传输的飞机还支持空中碰撞，避免系统以及交通碰撞和避免系统。

Transponders can be integrated into chipped car keys. When a transponder key is inserted or a key fob is pushed, a receiver in the ignition's circuitry picks up the signal. If the transponder's serial number matches the car's programmed number, the vehicle starts when the user inserts the key or pushes the start button.

电子收费系统使用安装在车辆挡风玻璃上或车牌读取器上的应答器来启用无现金收费。例如，佛罗里达收费公路使用预付费帐户（例如Sunpass和E-Pass）在全州的收费公路和桥梁上收集通行费。这消除了对载人电话的需求。

发件类型

Transponders can be either passive or active. Apassive transponder enables a computer or robot to identify an object. Magnetic labels -- such as those on credit cards and store items -- are common examples. A passive transponder must be used with an active传感器that decodes and transcribes the data the transponder contains. The transponder unit can be physically tiny, and its information can be sensed up to several feet away.

在商业和私人飞机的位置，标识和导航系统中使用简单的主动发音。一个示例是射频标识（RFID) device that transmits a coded signal when it receives a request from a monitoring or control point. The transponder output signal is tracked, so the position of the transponder can be constantly monitored. The input (receiver) and output (transmitter) frequencies are pre-assigned. Transponders of this type can operate over distances of thousands of miles.

Sophisticated active transponders are used in communications satellites and on board space vehicles. They receive incoming signals over a range -- orband- 频率并同时重传信号。该设备类似于陆基蜂窝电话网络中使用的中继器类型。传入信号通常起源于地球表面上的点，称为uplink。通常发送到表面上的点或区域的传出信号称为下行链路。这些应答器有时会在星际范围内运行。

Learn more about应答器s in RFID以及它们与供应链中的条形码使用相比。