New efficient structures using the one-hot residue number system (OHRNS) are presented. Normally the RNS uses a binary representation for the residues, though recently there has been renewed interest in the OHRNS, whi...
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ISBN:
(纸本)0819445584
New efficient structures using the one-hot residue number system (OHRNS) are presented. Normally the RNS uses a binary representation for the residues, though recently there has been renewed interest in the OHRNS, which uses a simple, but novel representation for the residues. The basic component of the OHRNS is the barrel shifter, making the OHRNS suitable for very high speed applications. The first of the new structures presented reduces the power dissipation in OHRNS adder trees. A modification to the normal barrel shifter is proposed, which reduces the power dissipated by as much as 30%. This improvement is obtained through the use of the modified barrel shifter and the appropriate connection of active-low and active-high stages. This overall power reduction offers the possibility of using the OHRNS in place of a typical full adder based tree in high speed DSP applications. A new storage register for one-hot representations is detailed, which overcomes the problem of having to use a large number of registers. A new architecture is presented for fast OHRNS sign detection. Sign detection is complex and slow to perform in the RNS. A mixed radix conversion (MRC) is typically used for sign detection in the OHRNS. The new sign detection architecture is based on a new property of the Chinese Remainder Theorem (CRT) and is significantly faster than the MRC approach for large moduli sets. Simulation results using SPICE are detailed for the new structures.
Speech is metered if the stresses occur at a nearly regular rate. Metered speech is common in poetry, and it can occur naturally in speech, if the speaker is spelling a word or reciting words or numbers from a list. I...
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ISBN:
(纸本)0819445584
Speech is metered if the stresses occur at a nearly regular rate. Metered speech is common in poetry, and it can occur naturally in speech, if the speaker is spelling a word or reciting words or numbers from a list. In radio communications, the CQ request, call sign and other codes are frequently metered. In tactical communications and air traffic control, location, heading and identification codes may be metered. Moreover metering may be expected to survive even in HF communications, which are corrupted by noise, interference and mistuning. For this environment, speech recognition and conventional machine-based methods are not effective. We describe Time-Frequency methods which have been adapted successfully to the problem of mitigation of HF signal conditions and detection of metered speech. These methods are based on modeled time and frequency correlation properties of nearly harmonic functions. We derive these properties and demonstrate a performance gain over conventional correlation and spectral methods. Finally, in addressing the problem of HF single sideband (SSB) communications, the problems of carrier mistuning, interfering signals, such as manual Morse, and fast automatic gain control (AGC) must be addressed. We demonstrate simple methods which may be used to blindly mitigate mistuning and narrowband interference, and effectively invert the fast automatic gain function.
We introduce the use of multidimensional logarithmic number system (MDLNS) as a generalization of the classical 1-D logarithmic number system (LNS) and analyze its use in DSP applications. The major drawback of the LN...
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We introduce the use of multidimensional logarithmic number system (MDLNS) as a generalization of the classical 1-D logarithmic number system (LNS) and analyze its use in DSP applications. The major drawback of the LNS is the requirement to use very large ROM arrays in implementing the additions and subtraction and it limits its use to low-precision applications. MDLNS allows exponential reduction of the size of the ROMs used without affecting the speed of the computational process: moreover, the calculations over different bases and digits are completely independent, which makes this particular representation perfectly suitable for massively parallel DSP architectures. The use of more than one base has at least two extra advantages. Firstly, the proposed architecture allows us to obtain the final result straightforwardly in binary form, thus, there is no need of the exponential amplifier, used in the known LNS architectures. Secondly, the second base can be optimized in accordance to the specific digital filter characteristics. This leads to dramatic reduction of the exponents used and, consequently, to large area savings. We offer many examples showing the computational advantages of the proposed approach.
Third generation's wireless communications systems comprise advanced signal processing algorithms that increase the computational requirements more than ten-fold over 2G's systems. Numerous existing and emergi...
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ISBN:
(纸本)0769514715
Third generation's wireless communications systems comprise advanced signal processing algorithms that increase the computational requirements more than ten-fold over 2G's systems. Numerous existing and emerging standards require flexible implementations ("software radio"). Thus efficient implementations of the performance-critical parts as Turbo decoding on programmable architectures are of great interest. Besides high-performance DSPs, application-customized RISC cores offer the required performance while still maintaining the aspired flexibility. This paper presents for the first time Turbo decoder implementations on customized RISC cores and compares the results with implementations on state-of-the-art VLIW DSPs. The results of our studies show that the Log-MAP performance is about 50% higher that on an ST120, a current VLIW architecture.
The proceedings contains 56 papers from the conference on SPIE: advanced signal processing algorithms, architectures, and implementations XI. The topics discussed include: modulation frequency and efficient audio codi...
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The proceedings contains 56 papers from the conference on SPIE: advanced signal processing algorithms, architectures, and implementations XI. The topics discussed include: modulation frequency and efficient audio coding;application of wavelet- and wavelet-packet-transform to human skin data;Wigner distribution and pulse propagation;time-frequency analysis using sidelobe apodization;spectral phase algorithm for detecting and estimating pitch;and minimum entropy approach to denoising time-frequency distributions.
We use the Wigner distribution to study pulse propagation in a dispersive media and we show that it leads naturally to a particle view. Using the results obtained we develop a simple approximation method that evolves ...
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ISBN:
(纸本)0819441880
We use the Wigner distribution to study pulse propagation in a dispersive media and we show that it leads naturally to a particle view. Using the results obtained we develop a simple approximation method that evolves a pulse in time.
We present a method for writing the differential equation for the smoothed Wigner distribution that corresponds to the solution of an ordinary linear differential equation. The method can be applied on an, linear ordi...
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ISBN:
(纸本)0819441880
We present a method for writing the differential equation for the smoothed Wigner distribution that corresponds to the solution of an ordinary linear differential equation. The method can be applied on an, linear ordinary differential equation with constant or time-varying coefficients.
We review, recent work on defining the time-frequency moments of a signal. Expressions are given for moments dropt(m)drop(omega), and of all orders n, m, in terms of the amplitude and phase of the signal and spectrum....
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ISBN:
(纸本)0819441880
We review, recent work on defining the time-frequency moments of a signal. Expressions are given for moments dropt(m)drop(omega), and of all orders n, m, in terms of the amplitude and phase of the signal and spectrum. Knowing the time-frequency moments is of interest for a variety of reasons. including their potential utility as features for classification of nonstationary signals, and also because from the moments one call construct the time-varying spectral density, or approximate it using a few moments.
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