1. Field of the Invention
The present invention generally relates to digital receivers used at the input of a digital device to detect a digital signal and transmit it without error to the device. More specifically, the present invention relates to the design of digital receivers that may be used to receive noisy digital input signals.
2. Description of Related Art
Digital receivers are used at the input of digital devices, such as digital devices connected to a digital network. The receiver's function is to detect when a digital input signal is high or low, corresponding to digital ones and zeros, and pass that signal through to the digital device. It is of prime importance that the receiver accurately transmit the input signal, without error, and without introducing additional false digital data. This can be difficult when the digital input signal is noisy.
For use in high speed systems, it is desirable for the receiver to have the fastest possible response. However, receiver accuracy cannot be sacrificed to achieve higher speeds. When the digital input signal is guaranteed to be "clean", i.e., where the signal has little or no noise associated with it, the receiver can be designed to be very fast. Real world digital signals, on the other hand, often have a great deal of noise, particularly at the transitions between each low and high. In the presence of such noise, a high speed receiver may not accurately track the input signal as the noise at the transitions between each bit falsely switches the receiver.
The conventional solution to this problem is simply to slow down the receiver sufficiently that it does not respond the rapid voltage swings of noisy and poorly switched digital signals. This type of receiver design makes the devices that produce clean digital signals pay the penalty of slow receiver speed necessary to accommodate devices that do not produce clean signals.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a digital receiver that has a rapid response in the presence of clean, noise free, digital input signals and which has a slower delayed response in the presence of noisy signals.
Yet another object of the present invention is to provide a method of reducing the noise sensitivity of a receiver by varying the delay of the receiver according to the noise in the input signal.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.