Topic
Pulse-position modulation
About: Pulse-position modulation is a research topic. Over the lifetime, 3916 publications have been published within this topic receiving 72057 citations. The topic is also known as: PPM.
Papers published on a yearly basis
Papers
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01 Dec 1966
TL;DR: In this paper, an explanation of the high error rate and poor diversity action experienced with narrowband frequency-modulation radiotelegraph systems with fading multipath signals, even in the absence of noise is given.
Abstract: An explanation is given of the high error rate and poor diversity action experienced with narrowband frequency-modulation radiotelegraph systems with fading multipath signals, even in the absence of noise. The mechanism of occurrence of these residual errors is examined in detail, and they are shown to be due to a combined effect of the frequency modulation and spurious amplitude modulation of the signal, which together cause severe phase aberrations during the signal transitions at troughs in the fading. The spurious amplitude modulation is due to the removal of the higher-order frequency-modulation sidebands by the normal channel filters, and it is shown that a useful reduction in the residual-error rate and improved diversity operation may be achieved if the second-order sidebands reach the output of the channel-receiving filter at their correct level. A method of establishing this condition in a multichannel system with practical filters is described, but it is concluded that some increase in channel spacing in relation to modulation rate would be necessary to restrict interchannel interference.
Patent•
14 Apr 2010
TL;DR: In this paper, a comb-interleaved frequency division multiplex (CIFDM) modulation method was proposed to combine the advantages of known OFDM modulation with the advantage of conventional carrier modulation.
Abstract: The invention relates to a radio device having a novel comb-interleaved frequency division multiplex (CIFDM) modulation method that combines the advantages of known OFDM modulation with the advantages of conventional carrier modulation. In each case, the data stream to be transmitted is divided into two multi-carrier blocks, which are sent in an interlocked and frequency- and time-offset fashion. For each single sub carrier of a block, a classic modulation with a matched filter system is used; the guard interval is omitted. The spectral efficiency is considerably increased by an artificial zero crossing being introduced with each modulation symbol. During each zero crossing, the other block is transmitted and separated again in the receiver via a synchronous switch.
TL;DR: In this article, error performance in optical communication with differential pulse-position modulated optical carrier is discussed. And both threshold type and maximum value type of decision schemes are also considered, including the effects of several parameters, such as the number of time slots, the duty ratio, the extinction ratio, count dimension, the signal-to-background radiation power ratio, and the signal tothermal noise power ratio.
Abstract: Error performance in optical communication, where the information is transmitted by means of the differential pulse-position modulated optical carrier, is discussed. Additive independent background radiation and thermal noise are taken into account. Both threshold type and maximum value type of decision schemes are also considered. The effects of several parameters, such as the number of time slots, the duty ratio, the extinction ratio, the count dimension, the signal-to-background radiation power ratio, and the signal-to-thermal noise power ratio are discussed in detail. The detection characteristic of this system are made clear by comparison with a pulse-position modulation system.
01 Sep 2006
TL;DR: A new ST code is proposed that satisfies all of the construction constraints of the golden code and that has the additional advantage of being totally real making it suitable for low cost carrier-less UWB terminals.
Abstract: The golden code (Belfiore, 2005) is a 2 x 2 space-time (ST) code that achieves the best known performance with all constellations carved from Zopf[i]. On the other hand, impulse radio (IR) time-hopping (TH) ultra wideband (UWB) is a carrier-less baseband transmission technique. Therefore, being complex-valued, the golden code can not be associated with IR-UWB systems. In this paper, we propose a new ST code that satisfies all of the construction constraints of the golden code and that has the additional advantage of being totally real making it suitable for low cost carrier-less UWB terminals. Unlike the golden code that can be associated with all constellations carved from Zopf[i], the proposed code is optimal with binary pulse position modulation (PPM) which is a popular modulation scheme for TH-UWB. Moreover, the proposed scheme permits to achieve full transmit diversity with hybrid pulse position and amplitude modulations (PPAM) having two modulation positions.
01 Dec 2007
TL;DR: In this paper, performance analysis for an optical wireless link in the presence of atmospheric scintillation using OOK and M-ary PPM modulation schemes was carried out for a bit rate of 1 Gbps.
Abstract: Performance analysis is carried out for an optical wireless link in the presence of atmospheric scintillation using OOK and M-ary PPM modulation schemes. The bit error rate (BER) performance results evaluated at a bit rate of 1 Gbps show that system suffers significant penalty in required photon count per bit to achieve a given BER due to atmospheric scintillation effect. It is noticed that penalty is approximately 128.2, 186.7, 215 and 356.6 photons per bit corresponding to OPPM, QPPM, OOK and BPPM respectively at a scintillation variance of 0.01.