US 8,149,977 B2 · Recovering data samples

Abstract

An apparatus recovers synchronous data samples from an asynchronously over-sampled stream of data samples derived from an input signal the spectral characteristic of which is subject to variation. The apparatus comprises an FIR filter having an input for receiving the asynchronously over-sampled stream of data samples and for producing equalised asynchronous samples. A signal sample reconstruction means reconstructs the synchronous data samples from the equalised asynchronous data samples. An automatic gain control loop is responsive to the reconstructed data samples to apply gain control for producing gain controlled reconstructed samples. A timing recovery means is responsive to the gain controlled reconstructed samples to provide timing information to the signal sample reconstruction means. A coefficient adaptation control loop is responsive to equalised reconstructed asynchronous data samples substantially unaffected by the automatic gain control for adapting the FIR filter coefficients to the variations in the spectral characteristics of the input signal.

Claims15

Dependent claims

Apparatus for recovering synchronous data samples from an asynchronously over-sampled stream of data samples derived from an input signal, where spectral characteristics of the input signal are subject to variation, the apparatus comprising;

an FIR filter having an input for receiving the asynchronously over-sampled stream of data samples and operable to produce equalised asynchronous samples;
a signal sample reconstruction arrangement operable to reconstruct the synchronous data samples from the equalised asynchronous samples;
an automatic gain control loop responsive to a first slicing level error signal to apply gain control for producing gain controlled reconstructed synchronous samples;
a slicer arrangement responsive to the gain controlled reconstructed synchronous samples to produce the first slicing level error signal and responsive to reconstructed synchronous samples substantially unaffected by gain control to produce a second slicing level error signal;
a timing recovery arrangement responsive to the first error signal to provide timing information to the signal sample reconstruction arrangement;
and
a coefficient adaptation control loop, responsive to the second error signal to adapt the FIR filter coefficients to the variation in the spectral characteristics of the input signal.

4 more elements

A method of recovering synchronous data samples from an asynchronously over-sampled stream of data samples derived from an input signal, where spectral characteristics of the input signal are subject to variation, the method comprising;

applying an FIR filter to the asynchronously over-sampled stream of data samples to produce equalised asynchronous data samples;
reconstructing the synchronous data samples from the equalised asynchronous data samples;
applying automatic gain control to the reconstructed synchronous data samples in dependence on a first error signal to produce gain controlled reconstructed synchronous data samples;
slicing the gain controlled reconstructed synchronous data samples to produce the first error signal;
recovering timing information using the first error signal for use in reconstructing the synchronous data samples;
slicing reconstructed synchronous data samples substantially unaffected by the automatic gain control to produce a second error signal;
and
adapting the FIR filter coefficients to the variation in the spectral characteristics of the input signal in response to the second error signal.

5 more elements

Dependencies are inferred from the claim text.

Recovering data samples

Life of this patent

Recovering data samples

Life of this patent

Abstract

Claims15