DSP algorithms for carrier and timing recovery

申请人研究的总体目标是提高数字信息在双绞线、同轴电缆、光纤和无线电信道等模拟媒体上的传输速率。数字信息通过模拟信道发送的例子有蜂窝电话、数字电视和互联网。不幸的是，数字数据不能直接通过模拟介质发送。它必须转换成适合传输的模拟信号。把数字数据转换成适当的模拟信号或把模拟信号转换成适当的模拟信号的设备称为调制解调器。接收调制解调器的操作相当复杂，但它基本上由三部分组成。第一部分对输入的模拟信号进行采样，并将连续的模拟信号转换为数字序列。采样率通常是相当高的，例如这部分调制解调器可以将模拟信号转换成每秒2000万个数字的流。调制解调器的第二部分是关键的，需要复杂的处理。它必须使接收调制解调器中的时钟与发送调制解调器中使用的时钟同步。它通过分析数字流来做到这一点。调制解调器的第三部分使用同步时钟来帮助破译数字流并重建由发射机发送的数字数据。申请人对调制解调器的第二部分感兴趣。目的是找到一种更快，但更便宜的方法来同步时钟在接收调制解调器时钟发送调制解调器。这样，调制解调器可以在模拟信道上以更高的信息速率和更低的成本进行通信。

The general objective of the applicant's research is to increase the rate at which digital information can be communicated over analog media like twisted pair, coaxial cable, optical fiber and radio  channels. Examples of where  digital information is sent over an analog channel are cellular telephone, digital TV and the internet. Unfortunately, digital data can not be sent directly over an analog medium. It must be converted to an analog signal that is suitable for transmission. The device that converts the digital data to appropriate analog signal and visa versa is called a modem.   The operation of a receiving modem is quite complex, but it basically has three parts. The first part samples the incomming analog signal and changes the continuous analog signal into a sequence of numbers. The sampling rate is usually quite high, for example this part of the modem could convert the analog signal into stream of 20 million numbers per second. The second part of the modem is critical and requires sophistacted processing. It must synchronizes a clock in receiving modem to the clock that was used in the transmitting modem. It does this by analysing the stream of numbers.  The third part of the modem uses the synchonized clock to help decipher the stream of numbers and reconstruct the digital data that was sent by the transmitter. The applicant is interested in the second part of the modem. The intent is to find a faster and yet cheaper way to synchronize the clock in the receiver modem to the clock in the transmitter modem.  In doing so, modems could communicate over analog channels at higher information rates and at a lower cost.