Data regenerator with adjustable decision threshold and adjustable sampling instant
View Patent ↗A data regenerator is provided which contains a clock regenerator which includes a phase comparator and a clock generator and obtains a sampling clock signal from an input signal, and two sampling devices, a measurement and a sampling device. In both sampling devices, it is possible to adjust the decision threshold and the sampling instants separately. The function of the clock regenerator is not impaired as a result of this. The bit-by-bit comparison of the sampled binary signals yields comparison values which are fed to a controller. The controller determines the optimum decision threshold and the optimum sampling instant from the comparison values.
1. A data regenerator, comprising:
a phase comparator;
a clock regenerator, the clock regenerator and the phase comparator serving to recover a clock signal from a binary input signal;
a controller;
a first sampling device for sampling the binary input signal, serving as an operating sampling device, having a decision threshold and a sampling time instant which are set by the controller without interfering with the clock signal;
a second sampling device for sampling the binary input signal, serving as a measurement sampling device, having an independently adjustable sampling time instant and an independently adjustable decision threshold that are varied by the controller without interfering with the clock signal; and
a comparator circuit connected to the first and second sampling devices for bit-by-bit comparison of sampled binary signals from the first and second sampling devices;
wherein the controller varies the respective decision thresholds and the sampling time instants of the first and second sampling devices relative to the clock signal, based on the comparison values obtained in the process, and optimizes the decision threshold and the sampling time instant of the first sampling device.
2. A data regenerator as claimed in claim 1 , wherein each of the first and second sampling devices includes a series circuit which comprises a decision stage with an adjustable decision threshold, an adjustable delay element and a sampling flip-flop.
3. A data regenerator as claimed in claim 1 , wherein at least one of the sampling time instants and the decision threshold of the phase comparative is adjustable.
4. A data regenerator as claimed in claim 2 , wherein the phase comparator has approximately a same data propagation time as the first and second sampling devices and is used as an operating sampling device, and the first and second sampling devices are both used as measurement sampling devices, and wherein the data regenerator further comprises:
an evaluation device to which are fed the sample binary signals from the first and second sampling devices and from the phase comparator;
a first comparator circuit connected to outputs of both the first sampling device and the phase comparator and outputting a first comparison value; and
a second comparator circuit connected to outputs of both the second sampling device and the phase comparator and outputting a second comparison value, with the first and second comparison values being fed to the controller.
5. A data regenerator as claimed in claim 4 , wherein each of the first and second sampling devices and the phase comparator includes two signal paths in which bits of a binary signal are alternately stored, and the evaluation device includes separate comparator circuits for the mutually corresponding signal paths.
6. A data regenerator as claimed in claim 4 , wherein the first and second sampling devices, given optimized sampling, have different decision thresholds which lie above and below an optimized decision threshold of the phase comparator, and binary signals which are sampled bit-by-bit are used for an error correction.
7. A data regenerator as claimed in claim 4 , further comprising a display device connected to the controller, wherein the display device visualizes at least one of measured comparison value distributions and occurring comparison value distributions.