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Communication channel with undersampled interpolative timing recoveryCommunication channel with undersampled interpolative timing recovery description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20080084339, Communication channel with undersampled interpolative timing recovery. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001]The claimed invention relates generally to the field of data transmission systems and more particularly, but not by way of limitation, to a communication channel that employs undersampled interpolative timing to recover transmitted data. BACKGROUND [0002]Communication channels are generally used to process transmitted data. Such channels are useful in a variety of applications, such as telecommunications systems and data storage devices. [0003]In some communication channels, an input continuous (e.g., analog) signal is sampled to provide a corresponding series of discrete (e.g., digital) samples. A variety of data recovery techniques can then be applied to the discrete samples to reconstruct the informational content of the input signal. Such recovery techniques can include partial-response, maximum likelihood (PRML) and decision-feedback equalization (DFE). [0004]While it would appear that some informational content of the original input signal would be lost by converting the input signal to a series of discrete samples, this is not necessarily the case. The well-known Nyquist criterion generally provides that all of the informational content of a continuous signal can be recovered through sampling if the sampling rate is at least twice the highest frequency content (bandwidth) of the signal. This minimum sampling rate (twice the highest frequency) is referred to as the Nyquist rate. [0005]By way of illustration, it is well known that the upper frequency response of the human ear is on the order of about 20 kHz; that is, humans generally cannot hear frequencies above this upper frequency threshold. Compact disc (CD) audio specifications sample original continuous audio signals at a nominal sampling rate of about 44.1 kHz, which is slightly above twice this upper frequency response (e.g., 40 kHz). [0006]In this way, an original analog audio signal (e.g., a live performance) can be sampled at 44.1 kHz and the samples can be encoded and stored on a CD. During subsequent playback of the CD, the samples can be decoded and used to reconstruct an output analog signal that is fed to a speaker to produce a response that, to most hearers, is substantially indistinguishable from the original performance. Similar processing can be performed with other types of continuous signals such as composite video signals and transducer readback signals. [0007]While communication channels that sample at or above the Nyquist rate have been found operable, there nevertheless remains a continued need for improvements in the art to provide channels that carry out signal processing with increased levels of performance. It is to these and other improvements that preferred embodiments of the present invention are generally directed. SUMMARY OF THE INVENTION [0008]Preferred embodiments of the present invention are generally directed to an apparatus and method for processing transmitted data. [0009]In accordance with preferred embodiments, a communication channel includes a sampling circuit which performs lossy sampling of a continuous signal to provide a corresponding sequence of discrete samples at a sampling rate less than a Nyquist rate of the continuous signal. [0010]A processing circuit of the channel reconstructs an informational content of the continuous signal from the discrete samples. The processing circuit is further configured to insert at least one, and preferably multiple, additional samples into the sequence to increase an effective rate of said sampling, preferably to a level that meets or exceeds the Nyquist rate. [0011]An intermediate memory module preferably temporarily stores the samples in a memory space prior to reconstruction by the processing circuit. This allows the sampling and the subsequent processing to be decoupled and performed at different rates. [0012]The sampling circuit preferably comprises an analog-to-digital converter (ADC) of an analog front end (AFE). The processing circuit preferably comprises a digital back end (DBE) employing partial-response, maximum-likelihood (PRML) detection. The additional samples are preferably provided by an iterative timing recovery (ITR) block of the DBE. [0013]These and various other features and advantages which characterize the claimed invention will become apparent upon reading the following detailed description and upon reviewing the associated drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0014]FIG. 1 is an exploded view of a data storage device constructed and operated in accordance with preferred embodiments of the present invention. [0015]FIG. 2 is a generalized functional block diagram of the device of FIG. 1. [0016]FIG. 3 provides a generalized functional block diagram of relevant portions of communication channel circuitry set forth in FIG. 2 in accordance with preferred embodiments. [0017]FIG. 4 is a waveform of informational (spectral power) content of continuous signals processed by the circuitry of FIG. 3. [0018]FIG. 5 shows a simplified graphical representation of undersampling and the periodic insertion of additional samples by the circuitry of FIG. 3. [0019]FIG. 6 is a functional representation of relevant portions of the interpolative timing recovery (ITR) block of FIG. 3. [0020]FIG. 7 is a flow chart for a SIGNAL PROCESSING routine, generally illustrative of steps carried out in accordance with preferred embodiments of the present invention. Continue reading about Communication channel with undersampled interpolative timing recovery... Full patent description for Communication channel with undersampled interpolative timing recovery Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Communication channel with undersampled interpolative timing recovery patent application. Patent Applications in related categories: 20090289822 - Ad converter and data processing unit - An AD converter includes an input circuit, an operation circuit and a bus interface. The input circuit is provided with a pull-down circuit, which is capable of pulling down an analog signal input side of a sample-hold circuit whether an analog signal is inputted or not. The operation circuit is ... ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Communication channel with undersampled interpolative timing recovery or other areas of interest. ### Previous Patent Application: Analog front end device Next Patent Application: Dither technique for improving dynamic non-linearity in an analog to digital converter, and an analog to digital converter having improved dynamic non-linearity Industry Class: Coded data generation or conversion ### FreshPatents.com Support Thank you for viewing the Communication channel with undersampled interpolative timing recovery patent info. IP-related news and info Results in 0.15252 seconds Other interesting Feshpatents.com categories: Qualcomm , Schering-Plough , Schlumberger , Seagate , Siemens , Texas Instruments , 174 |
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