Data processing: speech signal processing – linguistics – language – Speech signal processing – For storage or transmission
Reexamination Certificate
2000-02-15
2004-04-06
Dorvil, Richemond (Department: 2654)
Data processing: speech signal processing, linguistics, language
Speech signal processing
For storage or transmission
C379S093090
Reexamination Certificate
active
06718297
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to signal processing in a communication system and more particularly to classifying an input signal as either voice or data.
BACKGROUND OF THE INVENTION
For the most part, telecommunication systems were originally envisioned for voice signal transmission. Following its inception and implementation, however, pronounced changes have occurred in the telecommunication industry. Not only has voice communication via the telecommunication system become prolific through out the world, the presence of preexisting telephone lines has also made the telecommunication system a major media for data signal transmission. For example, many households and businesses in the United States and many foreign countries include telecommunication systems that are used for both the transmission of voice signals via a telephone and data signals via modem technology. As such, today's telecommunication systems not only transmit an increasing number of voice signals, but are also used as a major throughput for data signals.
With the increased use of the telephone communication system for both voice and data signals, systems and methods have been developed to narrow the required bandwidth needed to transmit voice signals, such that more voice and data may be transmitted on existing telephone lines. For example, many of today's telecommunication systems use encoding techniques to encode voice signals for transmission in telecommunication systems. These encoding techniques allow more information to be transmitted within the limited bandwidth of the telecommunication system.
Although encoding of voice signals is advantageous, implementation of voice encoding techniques in telecommunication systems can be somewhat problematic. Specifically, most telephone lines are used for both voice and data transmission. However, encoding techniques used for encoding of voice signals may introduce errors if used to encode data signals. In light of this, voice/data discrimination systems and techniques have been developed to discern voice and data signals, such that voice signals may be encoded, while data signals may be left unaffected or encoded by a different encoding procedure. These voice/data discrimination systems typically analyze signals transmitted on the telecommunication system and classify communication signals as either voice or data. Voice signals are then encoded prior to transmission to increase the amount of voice and data that may be transmitted in the telecommunication system.
Although conventional voice/data discrimination systems provide viable methods for voice and data signal discrimination, they do have some drawbacks. For example, one drawback with conventional voice/data discriminators is that they are typically computational intensive and may require an undesired amount of energy for voice/data discrimination. For example, many conventional voice/data discrimination systems use multipliers, dividers, Fast Fourier Transform systems, neural networks, and many other types of computational schemes to analyze signals transmitted on telecommunication systems and accurately characterize the signals as either voice or data. While these conventional voice/data discrimination systems typically provide a system for accurately characterizing communication signals as either voice or data, the energy consumed in analysis of the communication signals may be unacceptable.
Specifically, many telecommunication systems are comprised of either thousands or millions of communication lines used for transmission of both voice and data signals. A dedicated voice/data discrimination systems is typically needed to discriminate between voice and data for each communication line. Although the energy consumption of each individual voice/discriminator due to computationally intensive analysis of the signals may be negligible, the use of a plurality of these conventional voice/data discriminators in a telecommunication system may consume an unacceptable amount of energy. This may be particularly problematic in systems where energy conservation is at a premium.
An additional problem is that some conventional systems differentiate between voice and data signals based on specific characteristics of the data signals. Specifically, in many telecommunication systems, such as systems that use modems, an initial set of tones may be transmitted across the telecommunication line to inform systems that a data signal, as opposed to a voice signal, is being transmitted. In light of this fact, some conventional voice/data discrimination systems analyze the initial portion of a telecommunication signal and classify the signal as either voice or data based on whether these initial tones are present. While these conventional voice/data discrimination systems typically provide convenient apparatus and methods for discriminating between voice and data signals, they are somewhat limited. Specifically, these conventional voice/data discrimination systems must be activated prior to transmission of the telecommunication signal in order to classify the data as either voice or data.
SUMMARY OF THE INVENTION
As set forth below, the apparatus and method of the present invention may overcome many of the deficiencies identified with discriminating between voice and data signals in a communication system. In particular, the present invention provides apparatus and methods for classifying communication signals as either voice or data with a limited number of computational instructions, (i.e., multipliers, dividers, etc.), such that the communication signals may be classified with reduced energy consumption. Additionally, the present invention, provides apparatus and methods that may discriminate between voice and data signals based on the communication signal, as opposed to specific signal characteristics at the beginning of the signal. As such, the apparatus and methods of the present invention may classify a telecommunication signal as either voice or data without requiring activation prior to beginning transmission of the telecommunication signal.
The present invention provides several embodiments for classifying a communication signal as either voice or data in a communication system. For example, one embodiment of the present invention provides an apparatus and method for classifying an input signal based on both an estimation of the central frequency of an input signal and the energy level of the input signal. The apparatus of this embodiment includes a frequency estimator for generating a frequency estimate value representing both the estimated central frequency of an input signal and the estimate of the energy level of an input signal. The apparatus also includes an energy estimator for generating an energy estimate value representing an estimate of the energy level of the input signal. Additionally, the apparatus of this embodiment includes a classification unit in electrical communication with both the frequency and energy estimators for classifying the input signal as either a voice or data signal.
In operation, both the frequency and energy estimators receive the input signal and generate respective frequency and energy estimate values of the input signal. These estimate signals are received by the classification unit and compared to a data threshold value. If the frequency estimate value is at least as great as the data threshold value, the classification unit classifies the input signal as data. Otherwise, the input signal is classified as a voice signal.
Importantly the apparatus of this embodiment uses both the frequency and energy estimate of the input signal to classify the input signal as either voice or data. Because the present invention uses rough estimates of these values, as opposed to more accurate estimations provided by computational intensive systems, the apparatus and method of the present invention can typically classify the communication signal as either voice or data with less energy consumption. Additionally, because the present invention analyzes the com
Carroll Edward James
Franklin Cheryl Jean
Pride, III Joseph Peebles
Alston & Bird LLP
Dorvil Richemond
Storm Donald L.
The Boeing Company
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