Adaptive noise filtering and equalization for optimal high speed multilevel signal decoding
First Claim
1. A system for processing digital signals comprising symbols propagated according to a period, the system comprising:
- a signal conditioning filter comprising a first stage for mitigating degradations of a digital signal that occur according to a first time scale, the first stage comprising a linear tapped-delay line filter tuned to the first time scale, the first time scale comprising a fraction of the period at which the symbols are propagated, and a second stage for removing signal distortions that occur according to a second time scale, the second stage comprising a linear tapped-delay line filter tuned to the second time scale, the second time scale being different than the first time scale and comprising a magnitude at least equal to the period at which the symbols are propagated; and
a signal integrity unit for controlling the signal conditioning filter by maximizing fidelity of the digital signals.
4 Assignments
0 Petitions
Accused Products
Abstract
A Signal Conditioning Filter (SCF) and a Signal Integrity Unit (SIU) address the coupled problem of equalization and noise filtering in order to improve signal fidelity for decoding. Specifically, a received signal can be filtered in a manner to optimize the signal fidelity even in the presence of both significant (large magnitudes of) ISI and noise. The present invention can provide an adaptive method that continuously monitors a signal fidelity measure. Monitoring the fidelity of a multilevel signal can be performed by external means such as by the SIU. A received signal y(t) can be “conditioned” by application of a filter with an electronically adjustable impulse response g(t). A resulting output z(t) can then be interrogated to characterize the quality of the conditioned signal. This fidelity measure q(t) can be used to adjust the filter response to maximize the fidelity measure of the conditioned signal.
-
Citations
23 Claims
-
1. A system for processing digital signals comprising symbols propagated according to a period, the system comprising:
-
a signal conditioning filter comprising a first stage for mitigating degradations of a digital signal that occur according to a first time scale, the first stage comprising a linear tapped-delay line filter tuned to the first time scale, the first time scale comprising a fraction of the period at which the symbols are propagated, and a second stage for removing signal distortions that occur according to a second time scale, the second stage comprising a linear tapped-delay line filter tuned to the second time scale, the second time scale being different than the first time scale and comprising a magnitude at least equal to the period at which the symbols are propagated; and a signal integrity unit for controlling the signal conditioning filter by maximizing fidelity of the digital signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A system for processing digital signals comprising:
-
a first filter stage comprising a first linear tapped-delay line filter tuned to a first time constant, the first time constant comprising a value that is less than a symbol period, for compensating for signal distortions tat occur within a single symbol period and for integrating over less than a symbol period in order to substantially reduce at least one of ringing, jitter, and noise; and a second filter stage comprising a second linear tapped-delay line filter tuned to a second time constant, the first time constant being smaller than the second time constant and the second time constant comprising value at least equal to a symbol period, the second filter stage for removing inter-symbol interference (ISI). - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A system for processing digital signals comprising symbols propagated according to a period, the system comprising:
-
a cascade of two linear filters, where each filter comprises a series of variable gain amplifiers connected by delay elements, each delay element for a respective filter having a same delay value, each linear filter equalizing a particular frequency band of a multilevel signal; the delay elements in the first filter being tuned to a fraction of the symbol period at which the symbols are propagated for compensating for signal distortions that occur within a single symbol period and for integrating over less than a symbol period in order to substantially reduce at least one of ringing, jitter, and noise; the delay elements in the second filter being tuned to a magnitude at least equal to the symbol period at which symbols are propagated for mitigating degradations that occur according to the period. - View Dependent Claims (19, 20, 21, 22, 23)
-
Specification