Showing papers on "Modulation index published in 2002"
7 Nov 2002
TL;DR: In this paper, a method for determining conditions for which switching angles in a multilevel converter can be chosen to produce the required fundamental voltage while at the same time cancelling out higher order harmonics is presented.
Abstract: A method is given to determine conditions for which the switching angles in a multilevel converter can be chosen to produce the required fundamental voltage while at the same time cancel out higher order harmonics. A complete analysis is given for a 7- level converter where it is shown that for a range of the modulation index m/sub I/, the switching angles can be chosen to produce the desired fundamental V/sub 1/=m/sub I/(s4V/sub dc///spl pi/) while making the 5/sup th/ and 7/sup th/ harmonics identically zero.
123 citations
TL;DR: In this paper, a third-order elliptic low-pass SI filter is implemented in a 0.3-MHz signal with a modulation index of 0.5, and the filter nominally operates with a clock frequency of 10 MHz, cutoff frequency of 1 MHz and a power supply of 2.3 V, while consuming 29 mW of power and processing input signals as large as 600-/spl mu/A peak differential.
Abstract: In this paper, digital CMOS switched-current (SI) circuits with low charge-injection errors are presented. These circuits are based on the operation of the switches at virtual-ground nodes to result in signal-independent charge injection. Based on this scheme, different topologies for the memory cell are discussed. To verify the theoretical concepts developed, a third-order elliptic low-pass SI filter is implemented in a 0.25-/spl mu/m digital CMOS process. The filter nominally operates with a clock frequency of 10 MHz, cutoff frequency of 1 MHz, and a power supply of 2.3 V, while consuming 29 mW of power and processing input signals as large as 600-/spl mu/A peak differential. The low-charge injection nature of the circuit is reflected in its low total harmonic distortion of -59 dB for a 0.3-MHz signal with a modulation index of 0.5.
39 citations
Patent•
29 Jan 2002TL;DR: In this paper, an autocorrelator detects the modulation power of the spreading code dither and the distance to a reflection can be estimated from the time delay that yields the highest autocorerelation value.
Abstract: Optical performance monitoring of a dense wave division multiplex optical communication system is immune to effects of stimulated Raman scattering. Each wavelength is modulated by an orthogonal spreading code dither signal having a predetermined modulation index. At a receiver, a portion of the aggregate optical signal is tapped and passes through a wavelength dependant optical delay filter. For each wavelength, the aggregate signal is multiplied by a synchronized copy of a respective spreading code and an autocorrelator detects the modulation power of the spreading code dither. The system can also be deployed as an optical reflectometer. For each autocorrelator, an aggregate reflected signal is multiplied by a copy of a spreading code having a respective different time delay. The distance to a reflection can be estimated from the time delay that yields the highest autocorrelation value.
19 citations
24 May 2002
TL;DR: In this article, the authors proposed novel guided-wave electrooptic single sideband (SSB) modulators consisting of a pair of traveling-wave electrodes and a Mach-Zehnder waveguide.
Abstract: Summary from only given. We propose novel guided-wave electrooptic single sideband (SSB) modulators consisting of a pair of traveling-wave electrodes and a Mach-Zehnder waveguide. Adopting the periodically domain-inverted structure with a spatial shift to LiNbO/sub 3/ or LiTaO/sub 3/ traveling-wave modulators, the modulation phase and the modulation index can be controlled arbitrary so that the SSB modulation characteristics are obtained with one microwave modulation signal and a DC bias signal.
9 citations
7 Aug 2002
TL;DR: In this paper, a 20 km fiber-optic transmission of a 156 Mb/s-DBPSK 60 GHz optical mm-wave signal with a new modulation technique employed; the dualmode phase shift keying modulation (DMPM) method that was proposed for the use in advanced mmwave fiber-radio systems based on the passive base stations (PBSs).
Abstract: Demonstrated successfully a 20 km fiber-optic transmission of a 156 Mb/s-DBPSK 60 GHz optical mm-wave signal with a new modulation technique employed; the dual-mode phase shift keying modulation (DMPM) method that we have proposed for the use in advanced mm-wave fiber-radio systems based on the passive base stations (PBSs). The experiment was performed to investigate the DMPM performance from a realistic viewpoint, and the following attractive features were confirmed for its PBS application; high modulation index, high dispersion tolerance and compactness.
9 citations
1 Jan 2002
TL;DR: In this article, the selected harmonic eliminated PWM technique for three-level NPC Inverter-Fed AC Drives is analyzed and the maxim modulation index of the SHE-PWM for the NPC inverter is analyzed.
Abstract: This paper analyzes the selected harmonic eliminated PWM technique for three-level NPC Inverter-Fed AC Drives For the difficulty of determining the initial values when solving the SHE-PWM nonlinear equations, this paper proposes a method that using the differentiation of tbe solutions to predict the initial values The initial values equations when the modulation index m is equal to zero are also given The calculation results proved that numerical algorithm using this initial value method will convergent to the desired solutions fastThrough the calculation results, the maxim modulation index of the SHE-PWM for the NPC inverter is analyzed The calculation results are confirmed by test results
7 citations
Patent•
22 May 2002
TL;DR: In this paper, the authors proposed an integrated type optical multiplying modulation device which has an improved response speed when turning on/off or modulating a high frequency signal because a distance between a filter and a modulator can be shortened by especially miniaturizing a device as to the optical multiplying modulator capable of easily providing a higher-order sideband wave even from a high-frequency signal having small amplitude.
Abstract: PROBLEM TO BE SOLVED: To provide an integrated type optical multiplying modulation device which has an improved response speed when turning on/off or modulating a high frequency signal because a distance between a filter and a modulator can be shortened by especially miniaturizing a device as to the optical multiplying modulation device capable of easily providing a higher-order sideband wave even from a high frequency signal having small amplitude as compared with conventional phase modulation constitution having a high modulation index. SOLUTION: In a device having constitution for obtaining a sideband wave of high order by leading a laser beam into a kind of a light reflecting resonator and modulating the light plural times during the going and returning of the light in the resonator, a band limiting filter for passing only a sideband wave more than the order of a required sideband wave, a 1st reflection means, an optical modulator and a 2nd reflection means are integrally formed on the same substrate. Consequently, a miniaturized optical multiplying modulation device having a high response speed can be obtained.
5 citations
10 Dec 2002
TL;DR: In this paper, a new approach to reduce the harmonics generated by a three-phase diode rectifier is proposed to realize sinusoidal input current waveforms with low electromagnetic interference and arbitrary output voltage.
Abstract: In this paper, a new approach to reduce the harmonics generated by a three-phase diode rectifier is proposed. The proposed approach uses input filters, 6 controllable switches, a high frequency isolation transformer and a three-phase diode rectifier. A novel pulse-width modulation (PWM) scheme implemented in an XC4006 field programmable gate array (FPGA) modulates the switching of the controllable switches. This approach realizes sinusoidal input current waveforms with low electromagnetic interference and arbitrary output voltage. The output voltage can be controlled by variation of the modulation index between in the range (0/spl les/M/spl les/0.98). Experimental results to compare performance with and without the proposed approach are carried out to confirm its feasibility.
5 citations
1 Jan 2002
TL;DR: Based on the alternating series expansion of error probability function due to phase noise in PSK systems, the performance evaluation for Tikhonov and Gaussian probability distribution function was performed in this paper.
Abstract: Based on the alternating series expansion of error probability function due to phase noise in PSK systems, the performance evaluation for Tikhonov and Gaussian probability distribution function was performed in this paper In satellite link with a proper performance loss due to phase noise, the dependencies of errror performance for Tikhonov and Gaussian function were analyzed via loss evaluation By the related-definition for the phase noise spectral density and the modulation index for frequency modulation signal, the phase noise with 1/f characteristic was generated Using the generated phase noise as the input signal for digital satellite communication receiver, the performance loss due to the phase noise was measured and evaluated with the analyzed performance characteristics
4 citations
Patent•
29 Apr 2002
TL;DR: In this article, an arrangement having a signal processor is adapted to receive a first signal having modulation representing information and having a first modulation index and to generate, in response to the first signal, a second signal having frequency modulation representing the information, having a second modulation index different from the first modulo index, and a demodulator coupled to the signal processor so as to receive and demodulate the second signal.
Abstract: In response to a first signal having modulation representing information and a modulation index, embodiments of the present invention generate a second signal that differs from the first signal in its modulation index, and demodulate the second signal. In one embodiment, an arrangement having a signal processor is adapted to receive a first signal having modulation representing information and having a first modulation index and to generate, in response to the first signal, a second signal having frequency modulation representing the information and having a second modulation index different from the first modulation index, and a demodulator coupled to the signal processor so as to receive and demodulate the second signal. In another embodiment, a method comprises the steps of providing a first signal having modulation representing information and having a first modulation index; generating, in response to the first signal, a second signal having modulation representing the information and having a second modulation index different from the first modulation index; and demodulating the second signal.
4 citations
5 Nov 2002
TL;DR: In this paper, the authors proposed a novel method in order to analyze the harmonic characteristics in the multilevel inverter, which reduced an amount of calculation and simplified the process of calculation by using the relationship between reference voltage and output phase voltage to load neutral.
Abstract: This paper deals with a novel method in order to analyze the harmonic characteristics in the multilevel inverter. Generally, the magnitude of harmonic components is different according to the carrier PWM techniques, modulation index (M/sub i/), and the level of multi-level inverter. The previous papers analyzed the harmonic characteristics from the viewpoint of the space vector. Hence, the calculation of the harmonic vector becomes difficult and complex in 4-level or more than 5-level. However, the proposed method of this paper reduced an amount of calculation and simplified the process of calculation by using the relationship between reference voltage and output phase voltage to load neutral. This paper analyzed the harmonic and it is applied to the multi-carrier PWM techniques in 5- level and other-level of cascaded inverter system.
Patent•
31 May 2002
TL;DR: In this article, the output of a light source which emits a light beam of a single wavelength is bisected to apply angle modulations of a different modulation index to the divided respective light beams by using the modulating signal of a sine wave or a cosine wave having the same frequency.
Abstract: PROBLEM TO BE SOLVED: To generate optical signals of multiple wavelengths necessary for wavelength multiplex transmission with an inexpensive constitution by using a method of combining simple sine wave modulations SOLUTION: The output of a light source 1 which emits a light beam of a single wavelength is bisected to apply angle modulations of a different modulation index to the divided respective light beams by using the modulating signal of a sine wave or a cosine wave having the same frequency The polarization planes of both light beams having mutually different modulation indexes are orthogonalized and multiplexed
Patent•
25 Oct 2002
TL;DR: In this article, a clock signal with a frequency fclk generated by the clock signal generator is given to a 1/N frequency divider, which converts the frequency of the clock signals into fclkn/n, where n is the minimum frequency of an EMI measurement band.
Abstract: PROBLEM TO BE SOLVED: To provide a clock signal transmission method by which a fundamental wave and harmonics of a clock signal in a transmission system of the clock signal from a transmission section to a reception section are not produced within an EMI(electromagnetic interference) measurement band and the clock signal can be transmitted within a comparatively narrow band. SOLUTION: A clock signal with a frequency fclk generated by a clock signal generator 10 in a clock signal transmission section 9 is given to a 1/N frequency divider 11, which converts the frequency of the clock signal into fclk /N. A frequency modulator 13 applies frequency modulation to an FM carrier with a frequency fc by using a signal with the frequency fclk /N. The frequency fc in this case is selected to be fc +fclk /N
Patent•
15 Oct 2002TL;DR: In this paper, the reception of a transponder signal with frequency transposition and with signal integrating a transposition pilot, when the pilot is affected by an interference frequency modulation and when the signal is received with a noise to signal ratio insufficient to enable real-time tracking of its frequency variations.
Abstract: The invention concerns the reception of a transponder signal with frequency transposition and with signal integrating a transposition pilot, when the transposition pilot is affected by an interference frequency modulation and when the transposition pilot is received with a noise to signal ratio insufficient to enable real-time tracking of its frequency variations. It consists in deducing from the modulating signal frequency and phase as well as the modulation index, frequency, phase and energy differences measured at reception, between the central line and the first lateral line of the transposition pilot modulation spectrum and in using at reception a demodulation carrier frequency modulated by a modulating signal having the detected phase and frequency, with modulation level corresponding to the one obtained. This enables to improve at reception the apparent noise to signal ratio of the signal received from a transponder using a transposition carrier affected by an interference frequency modulation.
Journal Article•
TL;DR: In this article, a method of DC voltage close loop control for Static Var Generator (SVG) is proposed, which is applied on SVG firstly and the effect of the parameters for example inductance, capacitor, carrier wave ratio, modulation index, on harmonic ratio of AC current is obtained through simulation and experimentation.
Abstract: The method of DC voltage close loop control for Static Var Generator (SVG) is proposed. SPWM technique is applied on SVG firstly. The effect of the parameters for example inductance, capacitor, carrier wave ratio, modulation index, on harmonic ratio of AC current is obtained through simulation and experimentation.
4 Jun 2002
TL;DR: In this paper, a matrix converter adjustable speed drive with a decision-making space vector modulation exhibiting minimum processing load was developed to enhance the performance of a TMS320C32 DSP-based system.
Abstract: To effectively ride through any voltage sag using a matrix converter adjustable speed drives requires a solution that exceeds conventional modulation techniques. Basically, the proposed strategy regulates the converter modulation index up to dynamic overmodulation if necessary, and secondly reduces the motor speed if the former action does not suffice. The key factor accomplished is to maintain full converter synchronization with the motor during the sag to provide immediate acceleration once the disturbance disappears. Further, a decision-making space vector modulation exhibiting minimum-processing load was developed to enhance the performance. The drive was experimentally verified under typical industry disturbances using a TMS320C32 DSP based system. Results obtained showed the effectiveness of the proposal for matrix converter adjustable speed drives.
13 May 2002
TL;DR: A new non data aided estimator of the modulation index of a CPM signal is proposed based on the observation that the inverse of the index is the smallest positive real number to which the C PM signal should be expanded in order to generate a sinusoid of frequency 1 over 2Ts.
Abstract: In this paper, a new non data aided estimator of the modulation index of a CPM signal is proposed. It is based on the observation that the inverse of the index is the smallest positive real number to which the CPM signal should be expanded in order to generate a sinusoid of frequency 1 over 2T s . The asymptotic behavior of the estimate is studied. If N is the sample size, the estimate is shown to converge to a non Gaussian distribution at rate 1 over N. Simulations results sustain our theoretical claims.
TL;DR: In this paper, a novel PWM scheme called inverted-sine PWM (ISPWM) was proposed, which uses a sinusoidal reference and an inverted sine carrier.
Abstract: The paper describes a novel PWM scheme called inverted-sine PWM (ISPWM) which uses a sinusoidal reference and an inverted-sine carrier. The ISPWM, when applied to a rectifier, has a better harmonic elimination and a higher average output voltage compared to a sine PWM (SPWM). The harmonic content of the ISPWM output for different values of the modulation index is computed and compared with that of a SPWM. The complete circuit for generating the ISPWM control signal for single and three phase ac-dc converters is developed. Experimental waveforms of voltages and currents are presented.
Patent•
9 Jan 2002
TL;DR: In this paper, a light frequency converter by multiple modulation capable of easily providing higher-order side band waves from a radio-frequency electric signal of a small amplitude, compared with a configuration using conventional phase modulation with a high modulation index set to a large amplitude modulation signal, is presented.
Abstract: PROBLEM TO BE SOLVED: To provide a light frequency converter by multiple modulation capable of easily providing higher-order side band waves from a radio-frequency electric signal of a small amplitude, compared with a configuration using conventional phase modulation with a high modulation index set to a large amplitude modulation signal. SOLUTION: This is a device provided with a configuration for obtaining high order side band waves by guiding laser light into a kind of an optical reflection resonator and modulating the light plural times while the light is reciprocating therein, and a narrow band filter for selecting a desired side band wave among them, and is able to provide light of a frequency having an integral multiple frequency difference of a modulation signal compared with the frequency of inputted laser light.
TL;DR: In this paper, a detailed theoretical analysis is presented to evaluate the combined influence of self-phase modulation (SPM) and group velocity dispersion (GVD) of optical fiber on the bit error rate (BER) performance of a heterodyne optical CPFSK system.
Abstract: A detailed theoretical analysis is presented to evaluate the combined influence of self-phase modulation (SPM) and group velocity dispersion (GVD) of optical fiber on the bit error rate (BER) performance of a heterodyne optical CPFSK system. The power penalty suffered by the system due to the combined influence of GVD and SPM is evaluated from the BER performance results. It is found that the penalty due to SPM at a BER of 10−9 is significant when the input power exceeds 7 dBm . Further, the CPFSK system with modulation index of 0.5 is less sensitive to the effects of GVD and SPM compared to the system with a modulation index of 1. The theoretical results are in conformity with the experimental results reported earlier.
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TL;DR: In this article, a nonlinear circuit with a mixer and an oscillator was modeled as a linear periodic time-varying circuit by assuming a small-signal input and output.
Abstract: A nonlinear circuit with periodic operation, such as a mixer and oscillator, can be modeled as a linear periodic time-varying circuit by assuming a small-signal input and output. This paper presents a method by which the transfer function of such a periodic time-varying circuit can be decomposed into phase and amplitude modulation components. Assuming a small input, the phase modulation component can be interpreted as a result of narrow-band phase modulation with a small modulation index. Thus, it suffices to consider only the first sideband. As regards the spectrum of the amplitude modulated signal, it suffices to consider only the first sideband, regardless of the modulation index. Thus, the two spectra corresponding to the upper and lower sidebands around the carrier are decomposed into narrow-band phase and amplitude modulation components, and the transfer function can be decomposed into phase and amplitude modulation components. By this method, it becomes possible to decompose the noise of the mixer and the oscillator into the amplitude noise and the phase, or to simulate AM-PM conversion. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 85(7): 29–37, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.1105
TL;DR: The proposed controller has excellent features such as wide error correction range and no limitation on the modulation index and is implemented in the half-bridge class-D amplifier.
Abstract: A new controller for a digital audio amplifier with bit stream input is proposed. The proposed controller has excellent features such as wide error correction range and no limitation on the modulation index. The controller is implemented in the half-bridge class-D amplifier and performance is verified through experiments.
1 Jan 2002
TL;DR: In this article, a microprocessor-based system is described which produces Sinusoidal Pulse Width Modulated (SPWM) signal that can be used for controlling the inverters of a single-phase induction motor.
Abstract: Modern AC drives are designed mostly around an induction motor. An induction motor is operated through inverter, which converts a DC voltage to an AC voltage. In MOSFET inverters the gate voltage of the MOSFET is changed by a Pulse Width Modulated (PWM) signal to produce an AC voltage from a DC input. In this paper a microprocessor-based system is described which produces Sinusoidal Pulse Width Modulated (SPWM) signal that can be used for controlling the inverters of a single -phase induction motor. Here a variety of PWM patterns are stored in a Look Up Table (LUT) in a ROM from which the appropriate pattern is generated according to the desired frequency and modulation index (M). This system may readily be extended for a three-phase motor.
5 Nov 2002
TL;DR: In this paper, a Simulink model is proposed to simulate a nonideal inverter and a modulator compensation is suggested to improve the behaviour of the inverter in sensor-less applications.
Abstract: An accurate model in order to simulate a nonideal inverter is complex In this work, a Simulink model is proposed The model implements all the structure of the power inverter and the nucleus of calculation of the modulation of the inverter to obtain the induction motor voltage This paper also studies the feasibility of knowing the specified voltage by building the signal from the control signal that the modulator sends to the inverter The interest is double First, the goal is to know the limit of neglecting the dead time In the other hand, to reduce the cost in sensor-less AC drives The voltage measurement part in the sensor-less drive can be omitted if the studied system is implemented The results show three main conclusions First, the influence of the modulator is a pure delay for any modulation index and for any frequency For nearly all applications, this delay (Tpwm) can be accepted Second, the blanking time causes more relevant deviations, especially for lower modulation indexes In this paper, a modulator compensation is suggested to improve the behaviour of the inverter in sensor-less applications The results have been experimentally verified Third, the response of the sensor-less system implemented with a modified system of voltage measurement is better than the systems that do not use modified models
4 Aug 2002
TL;DR: In this article, an integrated bandpass filter based on the f/sub T/integration technique is experimentally demonstrated for the first time in GHz frequency range, which offers enhanced performance compared to the originally introduced structure with lower supply voltage, more accurate frequency control and less chip area.
Abstract: An integrated bandpass filter based on the f/sub T/-integration technique is experimentally demonstrated for the first time in GHz frequency range The f/sub T/-integrator configuration employed offers enhanced performance compared to the originally introduced structure with lower supply voltage, more accurate frequency control and less chip area while still maintaining a wide frequency tuning capability Fabricated in 08 /spl mu/m-BiCMOS, the experimental filter obtains a centre frequency tuning over 200% (from 420MHz to 1320MHz) with -52dB THD for output current at 50% modulation index, 30dB spurious free dynamic range and 1dB-compression-point dynamic range of 37dB at Q = 14 The circuit operates at 18V-supply voltage with current consumption in each integrator varying from 19mA to 42mA for the entire tuning range
Patent•
26 Aug 2002TL;DR: In this paper, the authors proposed a modulation index h < 0,5 to increase the maximum permitted launch power of the optical signal, increase the receiver sensitivity and increase the spectral efficiency.
Abstract: To transmit a digital signal (DS) over an optical fiber link (SMF), the digital signal is modulated onto an optical carrier (OS) using frequency shift keying modulation at a modulation index of h<0,5. Under the impact of a non-linear transmission effect in the optical fiber, the use of a modulation index h<0,5 leads to an increase in maximum permitted launch power of the optical signal, increased receiver sensitivity and an increased spectral efficiency.
Patent•
1 Mar 2002
TL;DR: In this paper, the frequency carrier variable frequency modulator has a voltage control oscillator (310) modulating the frequency, a phase/frequency detector (340) determining the difference between a reference signal and the oscillator signal, and a pass band filter (350) detecting the offset frequency and setting the voltage controlled oscillator.
Abstract: The frequency carrier variable frequency modulator has a voltage control oscillator (310) modulating the frequency, a phase/frequency detector (340) determining the difference between a reference signal and the oscillator signal, and a pass band filter (350) detecting the offset frequency and setting the voltage controlled oscillator. An audio signal amplifier (360) generates two opposite voltage levels providing modulation together with a modulation index compensator (320) to the voltage controlled oscillator.
10 Nov 2002
TL;DR: In this article, a harmonic passively mode-locked fiber laser employing two saturable absorbers is presented, where one absorber is responsible for starting up the mode-locking process, while the other is optimized to provide a high modulation index of the cavity loss by optically pumping it above the band-gap.
Abstract: Summary form only given We present an harmonic passively mode-locked fiber laser employing two saturable absorbers - one absorber is responsible for starting up the mode-locking process, while the other is optimized to provide a high modulation index of the cavity loss by optically pumping it above the band-gap The unique aspect of this work is that the pulse organization is accomplished by modulating the 980-nm light used for both pumping the gain medium and optical modulation of the absorber We show that this approach can be used for efficient pulse synchronization to an external RF signal and for considerable reduction of the timing jitter In addition we demonstrate, for what is believed to be the first time, that optimized semiconductor saturable absorber mirror (SESAM) structures can provide modulation depth of the absorption by optical pumping, which is sufficient to initiate active mode-locking
20 Oct 2002
TL;DR: In this article, the generation of noncharacteristics harmonics in AC supply feeding adjustable speed drives is experimentally investigated, taking into account the effect of the modulation index, the DC filter cutoff frequency and the output frequency of the inverter.
Abstract: The generation of the noncharacteristics harmonics in AC supply feeding adjustable speed drives is experimentally investigated, taking into account the effect of the modulation index, the DC filter cutoff frequency and the output frequency of the inverter Test performed included a single ASD connected to the mains, two inverters connected to the DC link and two ASDs connected to the grid, all under balanced supply and load The behavior with an unbalanced supply and balanced load is also reported