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Showing papers on "Continuous phase modulation published in 2005"


Journal ArticleDOI
TL;DR: In this article, a single-carrier frequency domain equalization (SC-FDE) approach for continuous phase modulation (CPM) is proposed, and the methodology for maintaining phase continuity with a cyclic guard interval is presented.
Abstract: Single-carrier frequency-domain equalization (SC-FDE) is proposed for continuous phase modulation (CPM). Two different discrete representations of the CPM signal are obtained. One is an orthogonal representation obtained from the Gram-Schmidt orthonormalization procedure, and the other is obtained from Laurent's decomposition for binary CPM. The methodology for maintaining phase continuity with a cyclic guard interval is presented. Various optimal and suboptimal reduced-complexity approaches are suggested for SC-FDE of CPM signals. General full- and partial-response CPM waveforms, and specific examples of minimum-shift keying (MSK) and Gaussian MSK (GMSK) with BT=0.3 are investigated. Simulation results show that SC-FDE for CPM is an effective approach for CPM on channels having long impulse responses.

89 citations


Proceedings ArticleDOI
24 Oct 2005
TL;DR: In this article, the possibilities of using carrier-based, sine-triangle pulse-width modulation to generate voltages of different frequencies to actuate multi-phase electric machines are discussed.
Abstract: Using an expanded reference frame transformation expressed in the complex-variable form, the possibilities offered by multi-phase converters, using carrier-based, sine-triangle pulse-width modulation to generate voltages of different frequencies to actuate multi-phase electric machines are set forth. The generalized expressions for the modulation signals, including the neutral voltage component to be compared with the high frequency triangle waveform to synthesize reference voltages for both five and six-phase converter-electric machines are determined. How the inclusion of the neutral voltage affects the modulation signals and the voltage gain and waveform quality is discussed. Some experimental results of synthesized five phase converter voltage waveforms are provided to validate the voltage waveform synthesis using carrier-based generalized (dis)continuous pulse-width modulation for operation in both the under and over- modulation regimes.

78 citations


Journal ArticleDOI
01 Jan 2005
TL;DR: Novel linear and decision feedback equalization algorithms for continuous phase modulations (CPMs) are illustrated and numerical results evidence that the proposed techniques enable the use of CPMs over severely frequency selective wireless channels.
Abstract: In this paper, novel equalization algorithms for continuous phase modulations (CPMs) are illustrated. Both conventional (linear and decision-feedback) and turbo equalization techniques are derived using the Laurent decomposition of CPM signals. All of them operate in the frequency domain and process two samples of the received signal per channel symbol. Numerical results show that on one hand, conventional equalization strategies offer good performance for binary partial response signaling over severely frequency-selective wireless channels at a moderate complexity. On the other hand, there is evidence that turbo techniques provide a small energy saving at the price of a substantial computational burden.

72 citations


Journal ArticleDOI
TL;DR: In this paper, a multiple quasi-phase-matched wavelength converter based on the continuous phase modulation of a /spl chi/sup (2)/ grating for use in variable wavelength conversion was proposed.
Abstract: We propose a new multiple quasi-phase-matched wavelength converter based on the continuous phase modulation of a /spl chi//sup (2)/ grating for use in variable wavelength conversion. A numerical study shows that the proposed device exhibits a high conversion efficiency, flexible design, and robust fabrication tolerance. A waveguide device fabricated by annealed proton exchange agrees well with the numerical design. Fine-tuning the device enabled us to demonstrate variable wavelength conversion between signals on the standard optical frequency grid. Using the device, we also demonstrated fast (<100 ps) wavelength switching of 4-channel 40-Gb/s signals. The obtained results clearly show that the proposed multiple quasi-phase-matched devices will be useful when constructing future flexible photonic networks.

71 citations


Journal ArticleDOI
TL;DR: This paper proposes an approximation which significantly reduces the number of signal pulses and which minimizes the mean-squared error for an arbitrary set of modulation indexes, and shows the practicality of the proposed approximation.
Abstract: It is known that any multilevel continuous phase-modulated (CPM) signal with a single modulation index can be exactly represented by a sum of pulse-amplitude modulated (PAM) waveforms. In this paper, we show how multi-h CPM signals can also be represented in this manner. The decomposition is presented in general terms as a function of the alphabet size, modulation indexes, and phase pulse of the CPM scheme. The number of pulses required to exactly construct the signal is shown to increase over that previously given for single-h schemes; this increase is in proportion to the number of modulation indexes. We propose an approximation which significantly reduces the number of signal pulses and which minimizes the mean-squared error for an arbitrary set of modulation indexes. We show that this approximation can have two objectives: 1) to reduce the number of pulses in the same manner as has been proposed for single-h schemes; and/or 2) to reduce the number of multi-h pulses; we also show the conditions where this latter objective is most practical. We compare this minimum mean-squared error approximation with another method which was recently proposed for CPM. We also give numerical results on detection performance which demonstrate the practicality of the proposed approximation.

59 citations


Journal ArticleDOI
TL;DR: This paper presents a receiver design consisting of a single filter and a subsequent noncoherent sequence detector that outperforms the conventional discriminator detector for typical Bluetooth channels and devise efficient methods for combined NSD and forward error correction decoding.
Abstract: The design of power efficient receivers for Bluetooth systems is a challenging task due to stringent complexity constraints. In this paper, we tackle this problem and present a receiver design consisting of a single filter and a subsequent noncoherent sequence detector. This receiver outperforms the conventional discriminator detector by more than 4 dB for typical Bluetooth channels. Thereby, the proposed noncoherent sequence detection (NSD) algorithm is both favorably low complex as it operates on a two-state trellis and highly robust against channel phase variations caused by low-cost local oscillators. The particular filter design accomplishes effective out-of-band interference suppression. Different from previous work on sequence detector receivers published in the literature, we take possible variations of the Bluetooth modulation parameters into account, and we also devise efficient methods for combined NSD and forward error correction decoding. Hence, the presented receiver design is an attractive solution for practical Bluetooth devices.

42 citations


Journal ArticleDOI
TL;DR: In this article, the authors presented a simple variant of space-time coding based on minimum shift keying (MSK), an offset format, which gave much better performance than quadrature phase shift-keying (QPSK) for the same number of states.
Abstract: Recent papers have shown that space-time (ST) coding using continuous phase modulation has a number of advantages relative to linear modulation, among which is its constant envelope, which allows transmission with inexpensive and power-efficient Class C amplifiers. The present paper presents a particularly simple variant, ST coding based on minimum shift keying (MSK), an offset format. ST codes with offset modulation give much better performance than quadrature phase shift-keying (QPSK), for the same number of states, and the MSK ST decoding computational load is smaller than that of QPSK by a ratio that improves exponentially with the number of transmitter antennas. The relationship between offset and nonoffset modulation formats is explored and the effect of pulse shape is shown explicitly.

41 citations


Journal ArticleDOI
TL;DR: In this paper, a shape measurement method using one frame projected sawtooth fringe pattern is proposed, which is projected by a programmable liquid crystal display (LCD) projector and converted to a wrapped phase map without using phase shifting or Fourier transform and retrieved by a quality-guided phase unwrapping algorithm.

40 citations


Journal ArticleDOI
TL;DR: This paper develops reduced complexity LST-CPM receivers for single antenna systems and studies a reduced complexity Viterbi receiver for binary CPM, finding that the combination of sphere decoding with hard-decision iterative processing is effective in boosting performance with a controllable complexity increase.
Abstract: Layered space-time (LST) transmissions employing continuous phase modulations (CPM) are well motivated for both bandwidth- and power-limited multiantenna communications. However, one of the major challenges for LST-CPM is the high complexity it incurs with maximum likelihood (ML) detection. In this paper, we develop reduced complexity LST-CPM receivers. First, we consider single antenna systems. Specifically, we study a reduced complexity Viterbi receiver for binary CPM. Based on this design, we introduce differential encoding for a class of CPM signals and analyze its performance gain both theoretically and with simulations. Second, we focus on multiantenna LST systems with minimum shift-keying (MSK)-type modulations. With group nulling-canceling (NC) and low-complexity linear equalization, we convert a coded multiuser detection problem into an uncoded one with small equalization loss. We also find that the combination of sphere decoding with hard-decision iterative processing is effective in boosting performance with a controllable complexity increase. Both analytical and simulated performance confirm that the novel LST-MSK receiver exhibits markedly improved performance relative to conventional NC detectors with moderate complexity increase.

35 citations


Journal ArticleDOI
TL;DR: This paper presents a detector for multi-h CPM which is based on the PAM representation, and gives an exact expression for the pairwise error probability for the entire class of PAM-based CPM detectors over the additive white Gaussian noise (AWGN) channel and shows that this bound is tighter than the previously published bound.
Abstract: It is well understood that the pulse amplitude modulation (PAM) representation of continuous phase modulation (CPM) can lead to reduced-complexity detectors with near optimum performance. It has recently been shown that the PAM representation also extends to CPM schemes with multiple modulation indexes (multi-h CPM). In this paper, we present a detector for multi-h CPM which is based on the PAM representation. We also give an exact expression for the pairwise error probability for the entire class of PAM-based CPM detectors (single- and multi-h, optimal, and reduced-complexity) over the additive white Gaussian noise (AWGN) channel and show that this bound is tighter than the previously published bound for approximate PAM-based detectors. In arriving at this expression, we show that PAM-based detectors for CPM are a special case of the broad class of mismatched CPM detectors. We also show that the metrics for PAM-based detectors accumulate distance in a different manner than metrics for other CPM detectors. These distance properties are especially useful in applications with greatly reduced trellis sizes. We give thorough examples of the analysis for different single- and multi-h signaling schemes. We also apply the new bound in comparing the performance of PAM-based detectors with other reduced-complexity detectors for CPM.

34 citations


Journal ArticleDOI
TL;DR: An orthogonal space-time coded partial response continuous phase modulation (OST-PCPM) system with two transmit antennas that can achieve full diversity with arbitrary inner memory length and phase smoothing functions of CPM schemes is proposed.
Abstract: In this paper, an orthogonal space-time coded partial response continuous phase modulation (OST-PCPM) system with two transmit antennas is proposed. It can achieve full diversity with arbitrary inner memory length and phase smoothing functions of CPM schemes. Based on the orthogonality between signals from two transmit antennas and the proposed differential encoding scheme, a fast decoding algorithm is developed for some special cases. Simulation results show that this scheme can provide much better performance with a reasonable complexity, as compared to one transmit antenna CPM scheme. We also give a suboptimal decoding method that provides a tradeoff between complexity and performance.

Journal ArticleDOI
TL;DR: In the detection, a novel method based on the ergodic property of chaotic signal is developed to demodulate the embedded copyright information and can effectively remove the interference from the host image and improve the detection performance dramatically.
Abstract: This paper presents a novel technique for image watermarking based on chaos theory. Chaotic parameter modulation (CPM) is employed to modulate the copyright information into the bifurcating parameter of a chaotic system. The system output is a wideband signal and is used as a watermark to be inserted into the host image. In the detection, a novel method based on the ergodic property of chaotic signal is developed to demodulate the embedded copyright information. Compared to previous works on blind watermarking, the proposed technique can effectively remove the interference from the host image and, thus, improve the detection performance dramatically. Simulation results show that the ergodic CPM approach is effective for image watermarking in terms of noise performance, robustness against attacks, and payload. In addition, its implementation is very simple and the computation speed is fast. Compared to holographic transform domain method and the conventional spread spectrum watermarking scheme, the proposed technique is shown to be superior.

Proceedings ArticleDOI
31 Oct 2005
TL;DR: The novel capacity-calculation algorithm gives a reliable estimate of the capacity of continuous phase modulation schemes, and allows the production of a more generalized class of modulation schemes called generalized CPM, which have a higher capacity than traditional CPM schemes of comparable bandwidth.
Abstract: This paper calculates the capacity of continuous phase modulation (CPM) schemes, modeling CPM as a finite state machine. The novel capacity-calculation algorithm gives a reliable estimate of the capacity using minimal computer time. This algorithm allows the production of a more generalized class of modulation schemes called generalized CPM, which have a higher capacity than traditional CPM schemes of comparable bandwidth

Journal ArticleDOI
TL;DR: A novel maximum-likelihood (ML) based iterative carrier phase estimator is proposed for coded linear modulations over static phase channels and an efficient carrier phase recovery method is proposed to perform very close to that of a perfect coherent receiver.
Abstract: This letter considers carrier phase recovery in turbo receivers. Firstly, a novel maximum-likelihood (ML) based iterative carrier phase estimator is proposed for coded linear modulations over static phase channels. The proposed carrier phase estimator, combined with the iterative sum-product decoder, performs very close to, the Cramer-Rao bound. Moreover, for practical dynamic phase channels, an efficient carrier phase recovery method is proposed to perform very close to that of a perfect coherent receiver.

Journal ArticleDOI
TL;DR: In this paper, a novel modulation scheme for shifting the frequency of an optical beat signal by improving a conventional serrodyne system via time division multiplexing was developed. But the modulation scheme is not suitable for the use of optical beat signals and the phase linearly increases from zero phase to infinite phase.
Abstract: We have developed a novel modulation scheme for shifting the frequency of an optical beat signal by improving a conventional serrodyne system via time division multiplexing. This novel method acts as an endless phase modulator where the phase linearly increases from zero phase to infinite phase. With this method, we have shifted a 25-GHz carrier continuously up to 1-MHz offset with 43-dB spur-free dynamic range, which is 7 dB higher than an ordinary serrodyne method.

Journal ArticleDOI
TL;DR: This work proposes combining irregular repeat accumulate (IRA) codes with continuous phase modulation (CPM) and calls this irregular repeat CPM (IRCPM), and uses the EXIT chart/function method to optimize the degree profile.
Abstract: We propose combining irregular repeat accumulate (IRA) codes with continuous phase modulation (CPM) and call this irregular repeat CPM (IRCPM). In this scheme, CPM is used as the accumulator of IRA codes to explore its built-in phase accumulate property. A property of the degree-1 check node (doping node) ratio is investigated. We use the EXIT chart/function method to optimize the degree profile. We also provide the EXIT function for CPM when the SNR (Signal-to-noise ratio) is fixed. Numerical results show that this scheme converges up to 0.49 dB earlier (lower SNR) than the best found serially concatenated CPM (SCCPM).

Proceedings ArticleDOI
05 Oct 2005
TL;DR: In this paper, the optical carrier frequency is placed at the quadrature point of the positive or negative slope of the reflection response of the fiber Bragg grating (FBG) and the phase modulated light reflected from the two opposite slopes will have a π phase difference, which makes bipolar operation possible in an all-optical microwave signal processor or an optical code division multiple access system.
Abstract: In this paper, optical phase modulation to intensity modulation by the use of a fiber Bragg grating (FBG) based frequency discriminator is proposed and experimentally demonstrated. In the proposed approach, the optical carrier frequency is placed at the quadrature point of the positive or negative slope of the reflection response of the FBG. The phase modulated light reflected from the two opposite slopes will have a π phase difference, which makes bipolar operation possible in an all-optical microwave signal processor or an optical code division multiple-access system. Both the frequency and phase responses of the FBG are taken into account to build a theoretical model in a frequency domain. Phase modulation to intensity modulation conversion based on a Gaussian apodized FBG is experimentally implemented. The results confirm the theoretical analysis.

Journal ArticleDOI
TL;DR: A simple model with the continuous phase deviations of the clock signals considered as periodic signals in the band of the real disturbances is developed and Comparisons with the stochastic approach are presented.
Abstract: Phase-locked loops (PLLs) are designed to extract timing signals in telecommunication networks. Noise, cross-talk, inter-symbol interference, quantization noise, and signal distortion are responsible for oscillations in the time between two successive transitions of the clock or data signal. It appears as an accidental phase modulation superposed to the original signal. This phenomenon is called timing jitter and affects the integrity of the data recovering process and, as a consequence, the error bit rate is increased. This problem has been studied by treating the jitter as a band limited noise process and tolerance masks for the jitter amplitude and frequency are recommended for several network architectures. Here, we develop a simple model with the continuous phase deviations of the clock signals considered as periodic signals in the band of the real disturbances. Comparisons with the stochastic approach are presented.

Proceedings ArticleDOI
01 Jan 2005
TL;DR: A reduced-complexity detection scheme for shaped-offset quadrature phase-shift keying (SOQPSK), a highly bandwidth-efficient constant-envelope modulation, based on the well-known pulse amplitude modulation (PAM) representation of continuous phase modulation (CPM).
Abstract: In this paper we develop a reduced-complexity detection scheme for shaped-offset quadrature phase-shift keying (SOQPSK), a highly bandwidth-efficient constant-envelope modulation. The detector is based on the well-known pulse amplitude modulation (PAM) representation of continuous phase modulation (CPM). Since SOQPSK is a ternary CPM, we show how the binary-based PAM technique is extended to accommodate the ternary case. We demonstrate that a detector based on the first two PAM components requires a simple trellis of only 4 states. We show that near-optimum performance is achieved using this reduced-complexity detector. The potential complexity reduction can be quite large, since one version of SOQPSK requires a trellis of 512 states.

Proceedings ArticleDOI
01 Jan 2005
TL;DR: This paper proposes a simple orthogonal space-time block coding (OSTBC) technique for continuous-phase modulation (CPM), and shows that using the proposed technique ODs can be combined with any CPM scheme.
Abstract: In this paper, we propose a simple orthogonal space-time block coding (OSTBC) technique for continuous-phase modulation (CPM). Although the straightforward combination of orthogonal designs (ODs) and CPM was deemed impossible in [(X. Zhang and M.P. Flitz, 2003) and (G. Wang and X-G. Xia, 2004)], we show that this is easily accomplished with a burst-based approach. In fact, using the proposed technique ODs can be combined with any CPM scheme. After an appropriate ST combining at the receiver, the same detection techniques as in case of single-antenna transmission can be applied. This is a significant advantage over previously proposed ST coding schemes for CPM. We also derive accurate approximations for the bit error rate and the frame error rate of CPM with OSTBC. Both analysis and simulations show in good agreement the excellent performance of the proposed scheme

Journal ArticleDOI
TL;DR: This paper presents a general feedforward symbol-timing estimation framework based on the conditional maximum likelihood principle and the proposed timing estimator is shown to be asymptotically equivalent to the classic square-law nonlinearity estimator under certain conditions.
Abstract: This paper presents a general feedforward symbol-timing estimation framework based on the conditional maximum likelihood principle. The proposed timing estimator presents reduced implementation complexity and is obtained by performing an approximation on the Fourier series expansion of the conditional maximum likelihood function. The proposed algorithm is applied to linear modulations and two commonly used continuous phase modulations: minimum shift keying (MSK) and Gaussian MSK (GMSK). For the linear modulations, it is shown both analytically and via simulations that the performance of the proposed estimator is very close to the conditional CRB and modified CRB for signal-to-noise ratios (SNRs) in the range SNR /spl les/ 30 dB. Furthermore, the proposed estimator is shown to be asymptotically equivalent to the classic square-law nonlinearity estimator under certain conditions. In the case of MSK and GMSK modulations, although the proposed algorithm reaches the conditional CRB at certain SNRs, however, the conditional CRB is quite far away from the modified CRB, and there exists an alternative algorithm whose performance comes closer to the modified CRB. Therefore, the proposed estimator is more suitable for linear modulations than for MSK and GMSK modulations.

Journal ArticleDOI
TL;DR: Simulation results confirm that the advantages of the combination of the interleaved convolutional encoding and the spatial encoding are promising for various system parameters.
Abstract: We derive a novel space-time code (STC) design criterion for continuous-phase frequency-shift keying (CPFSK) over frequency-nonselective fading channels. Our derivation is based on a specific matrix that is related to the input symbols of the CPFSK modulators. With this code-design criterion, we propose a simple interleaved space-time encoding scheme for CPFSK modulation over frequency-nonselective correlated fading channels to exploit potential temporal and spatial diversity advantages. Such an encoding scheme consists of a ring convolutional encoder and a spatial encoder, between which a convolutional interleaver is placed. A decoding algorithm that generates symbol metrics for the Viterbi decoder of convolutional codes from the spatial modulation trellis is examined. Simulation results confirm that the advantages of the combination of the interleaved convolutional encoding (for temporal diversity) and the spatial encoding (for spatial diversity) are promising for various system parameters.

Journal ArticleDOI
TL;DR: A blind estimator of the technical parameters of continuous phase modulated (CPM) signals consists in estimating jointly the modulation index, the symbol period and the frequency offset and the asymptotic behavior of the estimation error is studied.
Abstract: In this paper, a blind estimator of the technical parameters of continuous phase modulated (CPM) signals is proposed. It consists in estimating jointly the modulation index, the symbol period and the frequency offset. It is based on the following observations. First, the inverse of the index is the smallest positive real number a CPM signal should be raised to in order to generate a deterministic harmonic signal; second, the frequencies of the harmonic signal are simply related to the symbol period and the carrier frequency. The practical implementation of this joint estimator is described and the asymptotic behavior of the estimation error is studied. If N is the number of signaling intervals, the estimate of the modulation index is shown to converge to a non-Gaussian distribution at rate 1/N, while the estimate of the frequency offset and the estimate of the symbol period converge at rate 1/N/sup 3/2/. We also investigate the case where the modulation index and the symbol period are available at the receiver side. An estimator of the frequency offset is proposed by adapting the above joint estimator to the latter case. The asymptotic behavior of this estimator is studied and compared with the case where all of the parameters are unknown, so as to evaluate the possible degradation of the performance due to the ignorance of certain technical parameters. Simulations results sustain our theoretical claims.

Journal ArticleDOI
TL;DR: The results reveal that the proposed modulation scheme performs better than M-PolSK, M-DPSK, and M-FSK modulation schemes in terms of both power and bandwidth efficiencies, and same bandwidth efficiency can be obtained using different FPolSK modulation formats.
Abstract: In this paper, we propose a new modulation scheme based on combining frequency and polarization modulated signals, which we will refer to as hybrid frequency-polarization shift keying (FPolSK). The FPolSK modulation is basically an extension of the conventional M-PolSK modulation over orthogonal domains. This expansion enables representing signal constellation points over multidimensional space, which ensures increasing the geometric distances between these points, and in turn, improving the system power efficiency. On the other hand, compared with M-FSK modulation, FPolSK improves the bandwidth efficiency by employing less number of orthogonal frequencies to represent information symbols. Moreover, FPolSK is extremely useful for implementing communication systems that have limitations in power and bandwidth usage. This advantage comes from the fact that FPolSK inherently enables selecting the appropriate number of orthogonal frequencies that convey with system constraints. The contribution in this paper is threefold. First, we propose a design for the transmitter and the receiver of the FPolSK technique. Second, we perform analysis for the system power and bandwidth efficiencies. Third, we derive an expression for the system power spectral density (PSD). A performance comparison between the FPolSK modulation technique and previously developed techniques is also presented in this paper. Our results reveal that the proposed modulation scheme performs better than M-PolSK, M-DPSK, and M-FSK modulation schemes in terms of both power and bandwidth efficiencies. We have also found that same bandwidth efficiency can be obtained using different FPolSK modulation formats, and the PSD of the FPolSK modulation does not contain discrete components that are considered as a waste of power. Finally, the effects of the laser phase noise and fiber dispersion on the performance of the proposed modulation are also discussed in detail.

Patent
06 Jun 2005
TL;DR: In this article, a receiver generates log-likelihood-ratio-based soft bit metrics of precoded quaternary continuous phase modulation signals using four state-constrained trellises and a streamlined maximum likelihood sequence estimation Viterbi algorithm.
Abstract: A receiver generates log-likelihood-ratio-based soft bit metrics of precoded quaternary continuous phase modulation signals using four state-constrained trellises and a streamlined maximum likelihood sequence estimation Viterbi algorithm requiring no survivor state storage elements for a preferred error correction-coded quaternary Gaussian minimum shift keying communication system employing reduced-complexity pulse-amplitude modulation matched-filtering and soft-decision decoding.

Proceedings ArticleDOI
18 Mar 2005
TL;DR: Any modulation filtering method which satisfies these properties yields distortion-free results, and an implementation of modulation filtering, based on a short-time Fourier transform followed by independent coherent demodulation for each frequency channel is proposed.
Abstract: A two-dimensional representation, the "modulation spectrum", where the modulation frequency exists jointly with a regular Fourier frequency or other filter channel index, has previously been investigated. Accurate modulation filters offer, for example, new approaches for signal separation and noise reduction. However, a filtering operation on modulation frequency components has yet to be carefully defined. Most previous studies on modulation filtering assumed that the amplitude modulation envelope is real and non-negative, which has recently been shown to be incorrect. Distortions appear when the non-negative envelope assumption fails. Beginning with a more appropriate envelope assumption that allows the envelope to go negative, we propose three properties which modulation filtering systems should satisfy. Any modulation filtering method which satisfies these properties yields distortion-free results. An implementation of modulation filtering, based on a short-time Fourier transform followed by independent coherent demodulation for each frequency channel, is then proposed. Satisfaction of the properties is confirmed and an example result of modulation filtering on a speech signal is illustrated.

Proceedings ArticleDOI
01 Jan 2005
TL;DR: A space-time (ST) trellis encoded scheme with M-ary continuous phase frequency shift keying with a modulation index of 1/M (M-CPFSK) is presented and a system model that incorporates the Rimoldi decomposition of CPFSK is developed.
Abstract: A space-time (ST) trellis encoded scheme with M-ary continuous phase frequency shift keying with a modulation index of 1/M (M-CPFSK) is presented. A ST-M-CPFSK system model that incorporates the Rimoldi decomposition of CPFSK is developed. The Rimoldi decomposition separates the non-memory component of CPFSK from the memory component. The latter can be represented as a continuous phase encoder (CPE) and implemented with a ring convolutional encoder. The ST codes used here are linear ring convolutional codes. This allows the ST encoder and the CPE to be combined into one encoder, which can be represented by a single trellis and is easily implemented using delay elements, modulo-M adders and scalar multipliers.

Journal ArticleDOI
TL;DR: An iterative decoding approach to joint source and channel coding (JSCC) using combined trellis-coded quantization (TCQ) and continuous phase modulation (CPM) is proposed, using the structure of the TCQ encoder and the continuous phase modulator.
Abstract: An iterative decoding approach to joint source and channel coding (JSCC) using combined trellis-coded quantization (TCQ) and continuous phase modulation (CPM) is proposed. The channel is assumed to be the additive white Gaussian noise channel. This iterative procedure exploits the structure of the TCQ encoder and the continuous phase modulator. The performance in terms of the signal-to-distortion ratio (SDR) is compared with that of a combined TCQ/trellis-coded modulation (TCM) system. It is shown that the combined TCQ/CPM systems are both power- and bandwidth-efficient, compared with the combined TCQ/TCM system. For source encoding rate R=2 b/sample, it is observed that the combined TCQ/CPM systems with iterative decoding working at symbol level converge faster than the systems working at bit level. The novelty of this work is the use of a soft decoder and an iterative decoding algorithm for TCQ-based JSCC systems. The combined TCQ/CPM with iterative decoding is considered for the first time.

Proceedings ArticleDOI
01 Jan 2005
TL;DR: This paper presents a novel data transmitter using phase shift keying which can modulate the phase of the carrier within two carrier cycles, independent of the Q of the network; thus low power dissipation can be achieved.
Abstract: Inductive coupling is a common way to wirelessly transmit data to medical implants. In such applications, the carrier frequency is often limited to tens of MHz which is able to well penetrate the skin. To achieve high data rate, the number of carrier cycles used to modulate each bit should be as small as possible. This usually requires lowering the quality factor (Q) of the data transmission network, resulting in increased power dissipation. This paper presents a novel data transmitter using phase shift keying which can modulate the phase of the carrier within two carrier cycles, independent of the Q of the network; thus low power dissipation can be achieved. The transmitter is designed by taking advantage of the multiple-frequency resonant network of class-E power amplifiers. Design guidelines for such a Q-independent phase modulator are provided. Simulations and experimental results demonstrate that the phase modulator functions as expected

Patent
21 Dec 2005
TL;DR: In this paper, simplified non-coherent viterbi algorithm simplifies state of CPM signal as Sigman'; receiver processes the intermediate frequency signal to obtain complex baseband signal GammaB (t); the baseband signals multiplied by a delayed and shifted signal obtains baseband differential signal; according to grid chart, calculating branch measure of each state Sigma n+1'; then estimating not simplified ML state Sigma' n+ 1 (Sigma' n + 1), and tracing back to output code element.
Abstract: Being adopted for modulation method in the invention, waveform storing quadrature modulation includes steps: decomposing Phase Phi(t, Alpha) to Thetan and Theta (t, Alpha); building a corresponding look up table, storing their sine value and cosine value; through look up table to obtain sine value and cosine value of Thetan and Theta (t, Alpha); then through difference operation to obtain baseband signal. Being adopted for demodulation method in the invention, simplified noncoherent viterbi algorithm simplifies state of CPM signal as Sigman'; receiver processes the intermediate frequency signal to obtain complex baseband signal GammaB (t); the baseband signal multiplied by a delayed and shifted signal obtains baseband differential signal; according to grid chart, calculating branch measure of each state Sigma n+1'; then estimating not simplified ML state Sigma' n+1 (Sigma' n+1), and tracing back to output code element. Features are: easy of calculation and implementation and robustness.