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Showing papers on "Pulse-position modulation published in 2001"


Proceedings ArticleDOI
07 Oct 2001
TL;DR: To increase the data rate for future wireless systems, a novel scheme using multiple transmit antennas for space digital modulation is proposed, termed space shift keying (SSK).
Abstract: To increase the data rate for future wireless systems, a novel scheme using multiple transmit antennas for space digital modulation is proposed. In the scheme of space modulation, more than two antennas are employed to transmit and signal the information bits. The novel space modulation scheme is termed space shift keying (SSK). Numerical results are presented to examine the reception performance.

218 citations


Journal ArticleDOI
TL;DR: A numerical example is given that shows that impulse radio modulation is theoretically able to provide multiple-access communications with a combined transmission capacity of hundreds of megabits per second at bit error rates in the range 10/sup -4/ to 10/Sup -7/ using receivers of moderate complexity.
Abstract: Wireless spread spectrum multiple access (SSMA) using time hopping and block waveform encoded (M-ary) pulse position modulated (PPM) signals is analyzed. For different M-ary PPM signal designs, the multiple-access performance in free-space propagation renditions is analyzed in terms of the number of users supported by the system for a given bit error rate, signal-to-noise ratio, bit transmission rate, and number of signals in the M-ary set. The processing gain and number of simultaneous users are described in terms of system parameters. Tradeoffs between performance and receiver complexity are discussed. Upper bounds on both the maximum number of users and the total combined bit transmission rate are investigated. This analysis is applied to ultrawideband impulse radio modulation. In this modulation, the communications waveforms are practically realized using subnanosecond impulse technology. A numerical example is given that shows that impulse radio modulation is theoretically able to provide multiple-access communications with a combined transmission capacity of hundreds of megabits per second at bit error rates in the range 10/sup -4/ to 10/sup -7/ using receivers of moderate complexity.

214 citations


Journal ArticleDOI
TL;DR: A pseudo-chaotic modulation suitable for ultrawide-bandwidth impulse-radio communication systems, based upon controlling the symbolic dynamics of a chaotic map for encoding the digital information to be transmitted.
Abstract: In this paper, we propose a pseudo-chaotic modulation suitable for ultrawide-bandwidth impulse-radio communication systems. The coding scheme is based upon controlling the symbolic dynamics of a chaotic map for encoding the digital information to be transmitted. The pseudo-chaotic time hopping enhances the spread-spectrum characteristics of the system, by removing most periodic components from the transmitted signal. A maximum-likelihood detector for the proposed scheme is presented and its scalability features are illustrated. Finally, theoretical performance bounds for both soft and hard Viterbi decoding are derived and compared with the simulation results.

142 citations


Journal ArticleDOI
TL;DR: A new approach to communication with chaotic signals, which demonstrates good performance in the presence of channel distortions, and the possibilities of multiuser communication using CPPM and its advantages over standard communication techniques are discussed.
Abstract: Utilization of chaotic signals for covert communications remains a very promising practical application. Multiple studies indicate that the major shortcoming of recently proposed chaos-based communication schemes is their susceptibility to noise and distortions in communication channels. In this paper, we review a new approach to communication with chaotic signals, which demonstrates good performance in the presence of channel distortions. This communication scheme is based upon chaotic signals in the form of pulse trains where intervals between the pulses are determined by chaotic dynamics of a pulse generator. The pulse train with chaotic inter-pulse intervals is used as a carrier. Binary information is modulated onto this carrier by the pulse position modulation method, such that each pulse is either left unchanged or delayed by a certain time, depending on whether "0" or "1" is transmitted. By synchronizing the receiver to the chaotic-pulse train we can anticipate the timing of pulses corresponding to "0" and "1" and thus can decode the transmitted information. Based on the results of theoretical and experimental studies we discuss the basic design principles for the chaotic-pulse generator, its synchronization, and the performance of the chaotic-pulse communication scheme in the presence of channel noise and filtering. We also discuss the possibilities of multiuser communication using CPPM and its advantages over standard communication techniques.

118 citations


Patent
03 Jan 2001
TL;DR: In this paper, the authors combine the techniques of a transmitted reference (TR) and a multiple access scheme called delay hopping (DH) using UWB signaling, which results in a penalty in signal-to-noise ratio (SNR) over conventional PPM.
Abstract: An ultra-wideband (UWB) communications system combines the techniques of a transmitted reference (TR) and a multiple access scheme called delay hopping (DH). Combining these two techniques using UWB signaling results in a penalty in signal-to-noise ratio (SNR) over conventional pulse position modulation (PPM) techniques but avoids the synchronization difficulties associated with conventional approaches. The signaling pulse waveforms are designed to insure that their power spectral densities, after any frequency translation to the center of an operating band, are essentially spectrally disjoint with frequencies that must be protected. This TR technique is combined with the DH multiple access technique to create a UWB communications scheme that has a greater multiple access capacity than does the UWB TR technique by itself.

103 citations


Patent
07 Mar 2001
TL;DR: In this paper, a system and method for adaptive modulation of downstream communication between a wireless hub and a wireless modem on a selected downstream channel is provided, which allows for changing the downstream modulation on a packet by packet basis.
Abstract: A system and method for adaptive modulation of downstream communication between a wireless hub and a wireless modem on a selected downstream channel is provided. The adaptive modulation allows for changing the downstream modulation on a packet by packet basis. The downstream modulation is changed by specifying modulation parameters including any of a modulation format, symbol rate, and FEC for each packet. A super frame may be utilized that includes a header that specifies different modulation parameters for each of multiple data packets associated with the super frame. The modulated transmissions are sent on fixed bandwidth channels that are specified based on the bit rate of the modulated transmission.

96 citations


Proceedings ArticleDOI
10 Mar 2001
TL;DR: In this paper, the authors proposed an active ranging over a code-divisible multiple access (CDMA) communications channel with no carrier frequency, where each transceiver is given a unique pseudo-random noise code, which is broadcast using pulse position modulation (shifting pulses or monocycles forward or backward in time relative to an constant rate pulse train).
Abstract: Precision coordinated maneuvering of multiple space vehicles would offer significant performance advantages to both commercial and scientific missions by increasing the versatility and potential capabilities of the formation. Ultra-wideband systems can provide centimeter level accuracy ranging measurements over distances of kilometers, using only milliwatts of power from an omni-directional transceiver no bigger than a pager. Using these precise range measurements between the vehicles, it is possible to resolve the relative geometry of the entire formation. The ultra-wideband (UWB) system presented in this work is not RADAR; it is active ranging over a code divisible multiple access (CDMA) communications channel with no carrier frequency. Each transceiver is given a unique pseudo-random noise code, which is broadcast using pulse position modulation (shifting pulses or monocycles forward or backward in time relative to an constant rate pulse train), in a type of call and return scheme to measure time of flight between vehicles. As a byproduct of CDMA encoding, a UWB navigation system could also provide a megabit per second communications channel to each vehicle, providing further savings of power, weight, and cost. A simple ranging experiment has been designed as a proof of concept. The experiment includes bench top equipment for sending and receiving ultrawideband monocycles and post processing algorithms for determining range. To implement the system, it was necessary to design and develop ultra-wideband antennas to efficiently propagate the monocycle pulses with minimal distortion. These antennas were tested in an anechoic chamber constructed for the ranging experiment and data on their characterization is presented in this paper. This paper presents the experimentally derived ranging accuracies and compares them to theoretically derived ranging accuracies for the UWB based measurement. It also provides a characterization of the distortions encountered in the pulse waveform during transmission and reception from our custom antennas. UWB ranging systems offer a robust solution to relative vehicle navigation in a variety of space mission configurations.

90 citations


Proceedings ArticleDOI
01 Jan 2001
TL;DR: The channel capacity of M-ary pulse position modulation (PPM) ultra-wideband (UWB) communications over the additive white Gaussian noise channel is computed demonstrating a fundamental trade-off in UWB system design.
Abstract: We compute the channel capacity of M-ary pulse position modulation (PPM) ultra-wideband (UWB) communications over the additive white Gaussian noise channel. The computation extends the known capacity of PPM orthogonal signals to incorporate UWB-specific constraints. The constraints are the power spectrum density limitation under FCC Part 15 rules and a specified spreading ratio. The UWB capacity is expressed as a function of range demonstrating a fundamental trade-off in UWB system design. UWB capacity is also compared to the capacity of M-ary phase shift keying (PSK) direct sequence spread spectrum (DS-SS). It is shown that for the same power constraint,. both systems have similar capacity at high signal to noise ratio (SNR). At low SNR, UWB has a significant advantage for multilevel modulations with M>4, while for M=2,4, DS-SS has a slight advantage.

80 citations


Proceedings ArticleDOI
01 Jan 2001
TL;DR: It is shown that in case of narrowband interference (with respect to the spread spectrum bandwidth), UWB provides more effective interference suppression than DS-SS.
Abstract: In this paper we analyze the performance of ultra-wideband (UWB) communications in the presence interference. The interference is modeled as a zero mean random process with constant power spectral density over a certain bandwidth. Closed-form expressions are developed for the processing gain of a pulse position modulation UWB utilizing rectangular pulses. Simple approximations are obtained for special cases (narrowband and wideband interference). We compare the interference suppression properties of UWB and direct-sequence spread spectrum (DS-SS) under certain assumptions. It is shown that in case of narrowband interference (with respect to the spread spectrum bandwidth), UWB provides more effective interference suppression than DS-SS.

42 citations


Patent
20 Apr 2001
TL;DR: In this article, the A/D converter converts the video signal into a binary code having a preset bit length, which is then divided into a plurality of binary codes by the controller from the most significant bit to the least significant bit.
Abstract: A modulation circuit capable of high resolution pulse width modulation while keeping down the bit length and an image display provided with the modulation circuit. By the A/D converter 4 , the video signal Sv converted into a binary code having a preset bit length is divided into a plurality of binary codes by the controller 3 from the most significant bit to the least significant bit. Corresponding to the thus obtained plurality of divided binary codes, serial data is generated for producing a pulse current of a pulse width and current value according to the value of the binary code and is output to pulse width modulation circuits 1 cascade connected to the controller 3 . The pulse width modulation circuits supply LEDs 3 of the pixels pulse currents of pulse widths and current values corresponding to the serial data.

42 citations


Proceedings ArticleDOI
M.J. Manglani1, A.E. Bell1
28 Oct 2001
TL;DR: In this article, the performance of wavelet modulation in several time varying channels: Rayleigh, flat, slow fading channels and frequency selective, slow-fading channels was investigated.
Abstract: Wavelet modulation simultaneously sends data at multiple rates through an unknown channel. Previous research has demonstrated that wavelet modulation bit error rate performance in the additive white Gaussian noise channel is comparable to theoretical binary phase shift keying. We extend the investigation to the performance of wavelet modulation in several time varying channels: Rayleigh, flat, slow fading channels and frequency selective, slow fading channels.

Patent
20 Jun 2001
TL;DR: In this article, the PPM decoder circuit is calibrated to the difference between the external PPM frequency source and the internal clock-oscillator of the RFID tag device, which is performed in a single measurement during one calibration symbol period.
Abstract: A radio frequency identification (RFID) tag device having a pulse position modulation (PPM) decoder circuit which calculates a relative frequency relationship between an internal oscillator of the RFID tag device and an external PPM source such as a RFID tag reader. The PPM decoder circuit is calibrated to the difference between the external PPM frequency source (i.e., RFID tag reader) and the internal clock-oscillator of the RFID tag device, which is performed in a single measurement during one calibration symbol period.

Patent
05 Jul 2001
TL;DR: In this paper, a radio frequency identification (RFID) tag device having a pulse position modulation (PPM) decoder circuit calculates a relative frequency relationship between an internal clock-oscillator of the tag device and an external PPM source such as a RFID tag reader.
Abstract: A radio frequency identification (RFID) tag device having a pulse position modulation (PPM) decoder circuit which calculates a relative frequency relationship between an internal clock-oscillator of the RFID tag device and an external PPM source such as a RFID tag reader, and then synchronizes the RFID tag device PPM decoder circuit to the required precision for reliable PPM symbol decoding. The PPM decoder is synchronized by measuring the “counts per pulse” (CPP) from a calibration cycle having a plurality of pulses in a single symbol frame.

Journal ArticleDOI
TL;DR: It is shown that the proposed method significantly outperforms the uncoded systems for various receiver structures such as a correlator with and without hard-limiter and chip-level detector and in the presence of different values of dark current.
Abstract: In this paper, we consider using practical low-rate error correcting codes in fiber-optic code division multiple-access (CDMA) communication systems. To this end, a different method of low-rate channel coding is proposed. As opposed to the conventional coding schemes, this method does not require any further bandwidth expansion for error correction in fiber-optic CDMA communication systems. The low-rate channel codes that are used for demonstrating the capabilities of the proposed method are super-orthogonal codes. These codes are near optimal and have a relatively low complexity. We evaluate the upper bounds on the bit-error probability of the proposed coded fiber-optic CDMA system assuming both on-off keying and binary pulse position modulation schemes. It is shown that the proposed method significantly outperforms the uncoded systems for various receiver structures such as a correlator with and without hard-limiter and chip-level detector. Furthermore, the performance of the proposed coded fiber-optic CDMA system is also evaluated in the presence of different values of dark current.

Proceedings ArticleDOI
06 Feb 2001
TL;DR: It is shown that, DH-PIM offers higher bit rate and has a built-in frame synchronization capability and the optimum system performance in terms of optical power and bandwidth requirements is achieved at bit resolution of 5.12.
Abstract: 12 In this paper, we present a study of dual header-pulse interval modulation (DH-PIM) scheme for optical wireless communications. System theory and code properties of DH-PIM are discussed and expressions for the power spectral density, slow and packet error rates and optical power requirements are presented. The problem of baseline wander is also studied. The performance of DH-PIM is compared with other modulation schemes such as on-off keying (OOK), pulse position modulation (PPM), differential pulse position modulation and digital pulse interval modulation. We show that, DH-PIM offers higher bit rate and has a built-in frame synchronization capability. For a simple threshold detector receiver, it offers improved error performance compared with OOK, but marginally inferior performance compared with PPM. The optimum system performance in terms of optical power and bandwidth requirements is achieved at bit resolution of 5.

Journal ArticleDOI
TL;DR: The authors conclude that pulse-position modulation (PPM) with Gaussian pulses provides better performance than classic PPM schemes with rectangular pulses over unguided optical links operating at high bit rates.
Abstract: The authors conclude that pulse-position modulation (PPM) with Gaussian pulses provides better performance than classic PPM schemes with rectangular pulses over unguided optical links operating at high bit rates. In this fashion, both intersymbol interference (ISI), induced by multipath propagation, and the phase distortion effects due to the high-pass filter whose function is to suppress interference, are minimized. However, relevant improvement is not achieved if compared with the OOK format with Gaussian pulses and low duty cycle. The above conclusion is validated by the corresponding bit-error rate (BER) computation using Monte Carlo simulations.

Proceedings ArticleDOI
24 Jun 2001
TL;DR: Design criterion for space-time codes with continuous phase modulation (CPM) in a quasistatic fading channel is given and simulation results demonstrate their good performance.
Abstract: Design criterion for space-time codes with continuous phase modulation (CPM) in a quasistatic fading channel is given. Space-time codes are proposed and simulation results demonstrate their good performance.


Proceedings ArticleDOI
05 Nov 2001
TL;DR: A fundamentally different modulation scheme is discussed that leads to a receiver that is much less complex than an adaptive equalizer, and in many applications it is better to trade bit rate for longer operational life.
Abstract: Acoustic communication is an attractive option for networking distributed assets, such as UUVs, autonomous sensors, and other systems that must talk to one another in the ocean. The ocean is often a complex multipath channel and impressive progress has been made in developing equalization algorithms to overcome this. Unfortunately, many of these algorithms are computationally demanding and not as power-efficient as one would like; in many applications it is better to trade bit rate for longer operational life. For example, a wakeup function is intrinsically low rate but must be low power and highly reliable. We discuss a fundamentally different modulation scheme to address these requirements. An added benefit is that it leads to a receiver that is much less complex than an adaptive equalizer.

Journal ArticleDOI
01 Feb 2001
TL;DR: In this article, a chip-level detector for optical overlapping pulse-position modulation code-division multiple access (OPPM-CDMA) communication systems is proposed and compared to some traditional receivers under the constraints of fixed data rate and laser pulsewidth.
Abstract: A chip-level detector for optical overlapping pulse-position modulation code-division multiple-access (OPPM-CDMA) communication systems is proposed. The bit error rate of the proposed system is derived and compared to some traditional receivers under the constraints of fixed data rate and laser pulsewidth. These traditional receivers include OOK-, PPM- and OPPM-CDMA correlators. The throughput limitations of all these receivers are also presented and compared. The results reveal that a significant improvement in the performance is gained when using the proposed scheme. The throughput limitation of the OPPM-CDMA chip-level detection scheme is greater than that of an on-off keying CDMA correlation detection scheme by 7.5 times on average, when the bit error rate does not exceed 10/sup -9/.

Dissertation
01 Dec 2001
TL;DR: In this paper, a new modulation scheme called dual header pulse interval modulation (DH-PTh1) has been proposed for indoor optical channels, which is suitable for applications where there is a need for high throughput.
Abstract: Indoor optical wireless communication systems have been shown to be viable alternatives to radio systems for indoor networks because optical wireless systems offer a huge unlicensed bandwidth, high data rates, secure connectivity, immunity to electromagnetic interference and prevention from multipath fading. However, optical wireless systems are subject to multipath distortion and are governed by eye safety standards. Therefore, a modulation scheme is required that is capable of providing high speed and good immunity to multipath dispersion on indoor optical channels. In this thesis, a critical review of optical wireless systems and suitable modulation schemes has been presented. A new modulation scheme called dual header pulse interval modulation (DH-PTh1) is presented. A comprehensive theoretical analysis supported by computer simulations has been carried out to study characteristics of DH-PTh1. Novel expressions for the DH-PTh1 pulse train, symbol length, bandwidth requirement, packet transmission rate, transmission capacity, Fourier transform, power spectral density, slot and packet error rates and power requirement and penalty due to multipath propagation have been presented. Results from the analyses have been compared with OaK, PPM and DPTh1 modulation schemes. It has been shown that DH-PTh1 is a viable alternative scheme for indoor optical wireless communications, due to its built-in symbol synchronisation and relatively easy slot synchronisation. Compared with PPM and DPIM, DH-PIM offers shorter symbol lengths, improved transmission rates, increased transmission capacity, improved bandwidth requirement and better immunity to multipath dispersion when the dispersion is high. However these features are at the expense of a slightly higher optical power requirement and increased probability of error. The proposed scheme is suitable for applications where there is a need for high throughput.

Patent
07 Nov 2001
TL;DR: In this article, a space shift keying (SSK) modulation was proposed to carry information signal bits in a digital wireless communication with an antenna array, where the likelihood ratio test can be used to recognize the information signals transmitted from different array elements.
Abstract: A space shift keying (SSK) modulation is disclosed. At the transmitter of a digital wireless communication with an antenna array, due to the fact that multipath fading will cause different responses for distinct array elements, different information signal bits (such as the “0” and “1” in binary shift keying) can be sent from different array elements to the receiver site. At the receiver site, the likelihood ratio test can be used to recognize the information signal bits transmitted from different array elements. The present signaling method for carrying information signal bits is a digital modulation method, which is known as space shift keying modulation.

15 Feb 2001
TL;DR: In this paper, an avalanche photodiode (APD) array for ground-based optical communications receivers is investigated for the reception of optical signals through the turbulent atmosphere, where Kolmogorov phase screen simulations are used to generate realistic spatial distributions of the received optical fleld.
Abstract: An avalanche photodiode (APD) array for ground-based optical communications receivers is investigated for the reception of optical signals through the turbulent atmosphere. Kolmogorov phase screen simulations are used to generate realistic spatial distributions of the received optical fleld. It is shown that use of an APD array for pulse-position modulation detection can improve performance by up to 4 dB over single APD detection in the presence of turbulence, but that photoncounting detector arrays yield even greater gains. I. Introduction Ground-based reception of optical signals from space sufiers from degradation of the optical phase front caused by atmospheric turbulence, leading to a reduction in the efiective diameter of the receiving telescope and to random ∞uctuations of the point-spread function in the focal plane. A proportional increase in the receiver’s fleld of view in order to collect all of the signal also causes a corresponding increase in the amount of interfering background radiation, resulting in degraded communications performance. These problems may be mitigated through the use of an optical detector array assembly in the focal plane that can adaptively select areas of higher signal density while ignoring areas predominated by background noise. In [1], the performance of a detector array composed of photon-counting detectors was evaluated and found to yield up to a 5 dB improvement over a conventional single-detector photoncounting receiver. However, the current baseline receiver design for deep-space optical communication utilizes readily available avalanche photodiode detectors (APDs) rather than photon-counting detector arrays, which are still in the development stage at the wavelengths of interest for optical communications. In this article, we extend some of the results obtained in [1] to the APD array case.

Proceedings ArticleDOI
Hiroyuki Ishii1, S. Kawamura, T. Suzuki, M. Kuroda, H. Hosoya, H. Fujishima 
30 Sep 2001
TL;DR: An identification algorithm that can distinguish twelve kinds of modulation modes using a blind process aimed at automatic identification of unknown modulated signals is developed and the adaptive demodulation process is evaluated by using the developed system and confirmed its effectiveness.
Abstract: We developed an identification algorithm that can distinguish twelve kinds of modulation modes using a blind process aimed at automatic identification of unknown modulated signals. We also developed an adaptive receiver, installed this algorithm, and we carried out an experiment to evaluate the receiver's ability. By the result of the validation experiment, for linear digital modulation modes with S/N /spl ges/ 3 dB, for GMSK of nonlinear digital modulation modes with S/N /spl ges/ 18 dB, and for the FM of analog modulation modes with S/N /spl ges/ 12 dB, we got a performance of identification probability of over 90 % respectively. Furthermore, based on the identification results, we evaluated the adaptive demodulation process by using the developed system and confirmed its effectiveness.

Proceedings ArticleDOI
06 May 2001
TL;DR: An extension of the Chaotic Pulse Position Modulation is examined to the case in which the chaotic sequence is generated by an analog chaotic circuit instead of a discrete chaotic map, showing that chaos is preserved after the modulation phase.
Abstract: In this paper it is examined an extension of the Chaotic Pulse Position Modulation to the case in which the chaotic sequence is generated by an analog chaotic circuit instead of a discrete chaotic map. The suitability of the approach has been confirmed by carrying out a real case in which a Chua's circuit has been used, and showing that chaos is preserved after the modulation phase.

Proceedings ArticleDOI
17 Mar 2001
TL;DR: In this paper, the influence of self-phase modulation on duobinary and single sideband modulation was evaluated for a bit error ratio of 10/sup -9/ varying fiber length and input power.
Abstract: We present the influence of self-phase modulation on duobinary and single sideband modulation. Additionally we determine and compare the receiver sensitivity for a bit error ratio of 10/sup -9/ varying fiber length and input power.

Proceedings ArticleDOI
K. Heidary1
08 Jul 2001
TL;DR: The radiation characteristics of ultra-wideband (UWB) monopulse arrays are discussed in this paper and a model for the general UWB monopulse volume array has been developed.
Abstract: The radiation characteristics of ultra-wideband (UWB) monopulse arrays are discussed in this paper. The UWB arrays considered here consist of ultra-wideband sources radiating coded sequences of ultra-narrow Gaussian mono-pulses with very low duty cycle. A pseudorandom (PN) time-hopping spread spectrum technique is utilized for further spreading the signal spectrum and providing multiple access interference rejection, and secure communication. Pulse position modulation (PPM) at the rate of many pulses per data bit is used for data modulation. At the receiver correlation is applied and the PN code is used to discriminate between the desired and interfering signals. A model for the general UWB monopulse volume array has been developed. Mathematical formulas for parameters of interest have been derived and computed results have been presented.

Proceedings ArticleDOI
06 May 2001
TL;DR: A pseudo-chaotic modulation suitable for ultra-wide bandwidth (UWB) impulse radio is proposed and a maximum-likelihood detector is presented and its scalability features are illustrated.
Abstract: In this paper we propose a pseudo-chaotic modulation suitable for ultra-wide bandwidth (UWB) impulse radio. The coding scheme is based upon controlling the symbolic dynamics of a chaotic map for encoding the digital information to be transmitted. A maximum-likelihood detector is presented and its scalability features are illustrated.

Patent
28 Sep 2001
TL;DR: In this paper, the problem of arbitrarily generating a pulse modulation signal of a desired pattern in a simple structure and to achieve a precise and high gradation property of an image even when an operation speed is high is solved.
Abstract: PROBLEM TO BE SOLVED: To arbitrarily generates a pulse modulation signal of a desired pattern in a simple structure and to achieve a precise and high gradation property of an image even when an operation speed is high SOLUTION: This pulse modulation signal generating circuit 10 comprises a high frequency clock generating means 11 for generating a high frequency clock, a modulation data generating means 12 for generating modulation data representing a desired bit pattern according to the image data, and a serial modulation signal generating means 13 that converts the modulation data to a serial pulse chain based on the high frequency clock by receiving the modulation data to output the pulse modulation signal PM

Patent
01 Oct 2001
TL;DR: In this paper, a digital signal is transceived by a modulating time interval between portions of the first and second synchronization signals, and a first data pulse is transmitted during the frame.
Abstract: A system and method involve transceiving successive first and second synchronization signals defining endpoints of a frame. A digital signal is transceived by a modulating time interval between portions of the first and second synchronization signals. A first data pulse is transceived during the frame. A relative position in the frame of the first data pulse represents a first analog signal.