locked-in

Top PDF locked-in:

L'outil de communication technologique : un moyen de reprendre des décisions pour les personnes atteintes du Locked-in syndrome

L'outil de communication technologique : un moyen de reprendre des décisions pour les personnes atteintes du Locked-in syndrome

1.3.2 L'optimisation de la récupération motrice Dans la phase de récupération motrice, les actions de l'ergothérapeute portent sur : l'évaluation des possibilités motrices du patient, la réalisation d'adaptations simples qui permettent d'élever de façon notable la capacité motrice fonctionnelle (ex : surélever la main pour utiliser l'index,...) et la recherche de l'existence d'un mouvement fiable et reproductible. Celui-ci doit l'être dans le temps et dans les moments de panique que génère l'urgence. Ce mouvement permet d'actionner un contacteur adapté de type : sonnettes plates et sonnettes au souffle. Mais, concernant le Locked-in syndrome, les contacteurs musculaires (nécessitant une cotation d'au minimum 1 au testing musculaire) et associés à un buzzer sont généralement utilisés.
En savoir plus

85 En savoir plus

Interfaces cerveau-ordinateur, locked-in syndrome et troubles de la conscience

Interfaces cerveau-ordinateur, locked-in syndrome et troubles de la conscience

Dans la suite de ces études, cette nouvelle SSVEP- BCI indépendante du contrôle moteur a été évaluée comme outil de diagnostic et de communication avec des volontaires sains et des patients présentant un syndrome locked-in (participants LIS), ce qui n’avait jamais été testé auparavant. Pour le diagnostic, l’éva- luation de la réponse à une commande se fait hors ligne : le patient doit suivre les instructions et se concentrer sur les carrés jaunes et les carrés rouges, à la demande de l’opérateur ; l’ensemble des résultats est calculé après l’examen. Pour l’évaluation en tant qu’outil de communication, l’analyse est réalisée en temps réel : le patient répond à des questions simples posées par l’opérateur en se concentrant sur les carrés jaunes pour dire « oui » et les carrés rouges pour dire « non » ; les réponses sont directement calculées et transmises au patient et à l’opérateur par l’intermé- diaire d’un retour (feedback) auditif. Avec ce système, bien que deux tiers des volontaires sains aient été en mesure d’établir une communication fonctionnelle (i.e. dont les performances sont supérieures à 70 %), les performances atteintes par les participants LIS furent nettement plus faibles, avec un tiers des participants répondant à la commande et un quart capables de communiquer avec ce système.
En savoir plus

8 En savoir plus

Detecting consciousness in a total Locked-in syndrome: an active event related paradigm

Detecting consciousness in a total Locked-in syndrome: an active event related paradigm

4 Department of Nuclear Medicine, CHU Sart Tilman, Liège, Belgium 5 Department of Cognitive Sciences, University of Liège, Liège, Belgium 6 Department of Neurology, CHU Sart Tilman, Liège, Belgium Total locked-in syndrome is characterized by tetraplegia, anarthria and paralysis of eye motility. In this study, con- sciousness was detected in a 21-year-old woman who presented a total locked-in syndrome after a basilar artery thrombosis (49 days post-injury) using an active event-related paradigm. The patient was presented sequences of names containing the patient’s own name and other names. The patient was instructed to count her own name or to count another target name. Similar to 4 age- and gender-matched healthy controls, the P3 response recorded for the voluntarily counted own name was larger than while passively listening. This P3 response was observed 14 days before the first behavioral signs of consciousness. This study shows that our active event-related paradigm allowed to identify voluntary brain activity in a patient who would behaviorally be diagnosed as comatose.
En savoir plus

8 En savoir plus

Disembodied Mind: Cortical Changes Following Brainstem Injury in Patients with Locked-in Syndrome.

Disembodied Mind: Cortical Changes Following Brainstem Injury in Patients with Locked-in Syndrome.

Received: February 12, 2016 Revised: April 6, 2016 Accepted: April 11, 2016 Abstract: Locked-in syndrome (LIS) following ventral brainstem damage is the most severe form of motor disability. Patients are completely entrapped in an unresponsive body despite consciousness is preserved. Although the main feature of LIS is this extreme motor impairment, minor non-motor dysfunctions such as motor imagery defects and impaired emotional recognition have been reported suggesting an alteration of embodied cognition, defined as the effects that the body and its performances may have on cognitive domains. We investigated the presence of structural cortical changes in LIS, which may account for the reported cognitive dysfunctions. For this aim, magnetic resonance imaging scans were acquired in 11 patients with LIS (6 males and 5 females; mean age: 52.3±5.2SD years; mean time interval from injury to evaluation: 9±1.2SD months) and 44 healthy control subjects matching patients for age, sex and education. Freesurfer software was used to process data and to estimate cortical volumes in LIS patients as compared to healthy subjects. Results showed a selective cortical volume loss in patients involving the superior frontal gyrus, the pars opercularis and the insular cortex in the left hemisphere, and the superior and medium frontal gyrus, the pars opercularis, the insular cortex, and the superior parietal lobule in the right hemisphere. As these structures are typically associated with the mirror neuron system, which represents the neural substrate for embodied simulation processes, our results provide neuroanatomical support for potential disembodiment in LIS.
En savoir plus

9 En savoir plus

Organisation de l'information et stratégie à l'écrit dans le locked-in syndrome

Organisation de l'information et stratégie à l'écrit dans le locked-in syndrome

Conclusion Le locked-in syndrome transforme radicalement la vie des patients et de leur entourage. Changer son mode de communication principal de l'oral vers l'écrit, en particulier un écrit atypique reposant sur des mouvements autres que ceux des mains, n'est pas une mince affaire. Au niveau cognitif, la phase d'exécution motrice plus longue peut être plus demandeuse en ressources, notamment en mémoire de travail. Par ailleurs, le patient dépend de l'accès à son dispositif pour communiquer, cet accès étant déterminé pour certains par l'institution dans laquelle ils vivent, le temps accordé à l'écriture pouvant donc être limité et fractionné. Or, parfois, il s'agit du seul moyen ou du moyen principal dont ils disposent pour rester en contact avec certains proches ; dans ces conditions, nous avons voulu savoir si, sur le long terme, un patient développerait des stratégies pour optimiser son expression tout en limitant ses ressources. Nous avons analysé les lettres de F.G., patiente LIS depuis 30 ans, sous l'angle de l'organisation informationnelle. Nous avons constaté que la longueur des lettres augmentait avec le temps, et que l'emploi de structures syntaxiques permettant une plus grande intégration de l'information ne constituait vraisemblablement pas la stratégie adoptée par la patiente pour « en dire plus avec peu de mots ». Il semblerait plus utile d'aborder ces textes sous l'angle de l'implication de l'auteur et du destinataire, celui du genre, et celui de l'organisation dialogique du texte, ce qui fait sens quand on considère l'importance primordiale, dans le LIS, de la correspondance dans le maintien de la relation entre patient et entourage.
En savoir plus

68 En savoir plus

Organisation de l'information et stratégie à l'écrit dans le locked-in syndrome

Organisation de l'information et stratégie à l'écrit dans le locked-in syndrome

Conclusion Le locked-in syndrome transforme radicalement la vie des patients et de leur entourage. Changer son mode de communication principal de l'oral vers l'écrit, en particulier un écrit atypique reposant sur des mouvements autres que ceux des mains, n'est pas une mince affaire. Au niveau cognitif, la phase d'exécution motrice plus longue peut être plus demandeuse en ressources, notamment en mémoire de travail. Par ailleurs, le patient dépend de l'accès à son dispositif pour communiquer, cet accès étant déterminé pour certains par l'institution dans laquelle ils vivent, le temps accordé à l'écriture pouvant donc être limité et fractionné. Or, parfois, il s'agit du seul moyen ou du moyen principal dont ils disposent pour rester en contact avec certains proches ; dans ces conditions, nous avons voulu savoir si, sur le long terme, un patient développerait des stratégies pour optimiser son expression tout en limitant ses ressources. Nous avons analysé les lettres de F.G., patiente LIS depuis 30 ans, sous l'angle de l'organisation informationnelle. Nous avons constaté que la longueur des lettres augmentait avec le temps, et que l'emploi de structures syntaxiques permettant une plus grande intégration de l'information ne constituait vraisemblablement pas la stratégie adoptée par la patiente pour « en dire plus avec peu de mots ». Il semblerait plus utile d'aborder ces textes sous l'angle de l'implication de l'auteur et du destinataire, celui du genre, et celui de l'organisation dialogique du texte, ce qui fait sens quand on considère l'importance primordiale, dans le LIS, de la correspondance dans le maintien de la relation entre patient et entourage.
En savoir plus

68 En savoir plus

Consciousness in the Locked-in Syndrome

Consciousness in the Locked-in Syndrome

III. COMA AND RELATED CONDITIONS and the patient may erroneously be considered as being in a coma, vegetative state, or akinetic mutism [32] . In a recent survey in 44 LIS patients belonging to the French Association for Locked-in Syndrome (ALIS, see Box 15.1 ) the first person to realize the patient was conscious and could communicate via eye movements most often was a family member (55% of cases) and not the treating physician (23% of cases) [33] . Most distressingly, the time elapsed between brain insult and LIS diagnosis was on an average of 2.5 months (78 days). Several patients were not diagnosed for more than 4 years. Leon-Carrion et al . [33] believed that this delay in the diagnosis of LIS mainly reflected initial misdiagnosis. Clinical experience indeed shows how difficult it is to recognize unambiguous signs of conscious perception of the environment and of the self in severely brain-injured patients. Voluntary eye movements and/or blinking can erroneously be inter- preted as reflexive in anarthric and nearly completely paralyzed patients who classically show decerebra- tion posturing (i.e., stereotyped extension reflexes).
En savoir plus

13 En savoir plus

Assessment of needs, psychological impact and quality of life in families of patients with locked-in syndrome.

Assessment of needs, psychological impact and quality of life in families of patients with locked-in syndrome.

The quality of life of relatives of patients with acquired brain injury has been studied through semi-structured interviews and standardized measures [ 7 , 15 , 16 , 18 , 29 ] or more indirectly under other means which can be assimilated to a description or a component of quality of life such as stress, burden, strain or social functioning [ 10 , 13 , 17 , 19 – 21 ]. Despite the methodological differences, most studies agree on the findings of a decrease in the quality of life after the accident and a sense of overload [ 7 , 12 – 16 , 18 ]. In our group, most participants (58%) reported neutral to positives scores, which is in line with the findings of Koskinen [ 29 ] who found in a longitudinal study that most relatives reported a ‘rather good’ quality of life. They found that the main deterioration in the quality of life occurred during the first year after the injury and that there was stabilization over time but without reaching the levels prior to the injury. An important finding in our study was the significant correlation between the number of met/unmet needs and the quality of life in relatives, showing that the quality of life increased as the number of met needs increased, and that a lower quality of life was related to an increased number of unmet needs. In their study, Moules and Chandler also found a significant correlation between high levels of unmet needs and a perceived low quality of life in relatives of patients with traumatic brain injury [ 7 ].
En savoir plus

8 En savoir plus

Attitudes towards personhood in the locked-in syndrome: from third- to first- person perspective and interpersonal significance

Attitudes towards personhood in the locked-in syndrome: from third- to first- person perspective and interpersonal significance

Limitations Due to the methodology of this project, a few limitations must be acknowledged. First, the data was collected by an inexperienced researcher. The questions as well as the motivation for the survey, came from several con- versations among LIS patients about their subjective experience with home caregivers. The patient with LIS who initiated the survey was involved in the training of home caregivers, and wanted to raise awareness about the subjective experience of LIS patients in these inter- personal contexts. This organic, rather than theory-in- formed, process offers both strengths and weaknesses. To the first, it is rooted directly into the subjective experience of patients, thus reflecting the most salient aspects of their experience in a way that may elude a purely theory-driven approach insofar as the disability paradox highlights divergence between the first- and third-person perspectives. To the latter, this data merely illustrates the importance of these topics and our de- scriptive analysis aims at providing a proof of concept and encouragement to investigate how these behaviors interact with perceived personhood in the LIS. A second limitation is the small sample size, which is frequent in such populations. However, the very high response rate suggests that this topic was particularly engaging for the respondents. The high response rate is even more mean- ingful in response to open questions, which increase the communication burden for LIS patients, compared to multiple choice questionnaires or Likert scales. Finally, a third limitation comes from the descriptive and explor- atory nature of this analysis. We do not propose infer- ential statistics or a predictive model here, but rather describe qualitatively factors relevant to personhood experienced from the first-person perspective.
En savoir plus

9 En savoir plus

Why aren't they locked in waiting games? Unlocking rules and the ecology of concepts in the semiconductor industry.

Why aren't they locked in waiting games? Unlocking rules and the ecology of concepts in the semiconductor industry.

By contrast, certain rules can create paths. For instance, the rules invented and taught at the Bauhaus design schools by famous teachers such as Klee, Itten and Kandinsky unlocked cognitive paths. Itten’s course was an archetypal example of unlocking rules in art (Itten 1975) (Klee 1966): the laws of form, colour and shape helped students to disentangle too self-evident relationships between material-shape- colour-emotion and enabled them to explore beyond the clichés (“a warm fibrous wood”). We know the effects in term of generativity (famous objects, new grammars of forms, etc.). In engineering too, it has recently been shown that design theories and methods gain in generativity over time (Hatchuel et al. 2011). The generative power results from the rules set by the new design theories, which increase the capacity to rigorously use more diverse types of knowledge and to consciously break away from technological routines. These theories propose unlocking rules, to be embedded in the design reasoning. They can be as simple as: “in the case of an alternative between two solutions, design a third one.” They can be rules to inhibit the reuse of locking rules (eg rules to formulate design briefs such as “an aircraft without a piston engine”; “wood is not necessarily fibrous”; or “agriculture is not necessarily unsustainable”) or to encourage the opening of new ones (“an aircraft with fuel cells”).
En savoir plus

17 En savoir plus

A survey on self-assessed well-being in a cohort of chronic locked-in syndrome patients: happy majority, miserable minority

A survey on self-assessed well-being in a cohort of chronic locked-in syndrome patients: happy majority, miserable minority

during the acute stage of the condition, optimal life- sustaining care and revalidation can have major long- term benefit. Maybe, since low satisfaction with mobility and recreational activities were here associated with poor SWB, extra palliative efforts directed at these problems could be helpful. Also more vigorous treatment of anxiety may be valuable. Finally, our results also bear on existential and ethical issues. 42 Because they are cogni- tively intact, 43 LIS patients are competent to make decisions on whether to continue life in LIS or to ask for withholding or withdrawal of treatment or for physician- assisted death. 44 That half of the respondents professing happiness do not wish to be resuscitated in case of cardiac arrest complicates the interpretation of their statement of happiness. As for current wish for eutha- nasia, expressed by only four of the 59 subjects (7%) responding to this question, it must be taken into account that, unlike in Belgium, the Netherlands, Luxemburg, Oregon, Washington and Montana, eutha- nasia and physician-assisted suicide are not legally permitted in France, where the study was carried out. What do our data suggest regarding the practice of euthanasia or physician-assisted suicide? The principal clinical conditions for requests for physician-assisted death to be legally valid are ‘unbearable’ suffering and irreversibility of the situation. Whereas the first condi- tion may apply in some LIS patients, irreversibility cannot be ascertained until, after rehabilitation, their
En savoir plus

9 En savoir plus

Phase-locked dual-polarization fiber lasers as compact optical-microwave sources

Phase-locked dual-polarization fiber lasers as compact optical-microwave sources

conclusions are given in Section 6. 2. DUAL-POLARIZATION DFB FIBER LASERS The experimental set-up is shown in Fig. 1. We have investigated different samples of erbium- doped silica fiber lasers, all being made with a distributed-feedback (DFB) structure. The Bragg gratings are photo-induced using the phase-mask technique with a continuous-wave UV laser. The dual-polarization lasers studied here bear different grating profiles that are detailed below. In particular we will show results obtained with samples emitting beat notes at around 1 GHz (labeled 1G) and at 10 GHz (labeled 10G). The lasers are spliced to single-mode fibers (SMF) on both sides. All the lasers are pumped at 980 nm on the output coupler side through a standard 980/1550 wavelength-division multiplexer. The laser output is transmitted through an isolator, a polarization controller, and a polarizer, to the analysis instruments. The system is entirely single-mode (non PM) fibered. In the following, we concentrate our analysis on the dual-frequency performance of the DFB lasers, in order to define a suitable phase- locked loop for beat note stabilization, either at 1 GHz or at 10 GHz.
En savoir plus

8 En savoir plus

Investigation of Injection-Locked Quantum Cascade Lasers based on Rate equations

Investigation of Injection-Locked Quantum Cascade Lasers based on Rate equations

a) Electronic mail: cheng.wang@insa-rennes.fr bandwidth is 10 GHz. Besides, modulation bandwidths of 13 GHz and 24 GHz have also been reported on terahertz QCLs with a test bench technique 11,12 . Since the relaxation oscillation is responsible for the dynamic stability in the free-running laser, a slight external perturbation such as modulation, optical injection or self-injection is enough to induce sustained pulsating intensities 13 . Optical injection-locking technique is known to be an attractive approach for improving the modulation characteristics of directly modulated interband semiconductor lasers 14,15 . Indeed, optical injection can be very critical for increasing the modulation bandwidth, reducing the laser’s chirp, and suppressing the mode hopping phenomenon as well as the relative intensity noise 16-18 . For instance, a record relaxation resonance frequency of 72 GHz associated with a broadband response of 44 GHz has been reported in an injection-locked quantum well DFB laser. Such a bandwidth enhancement corresponds to a 5.5 fold improvement when compared to the free- running case 17 . A theoretical study has recently reported the impacts of optical injection on the modulation properties of QCLs 19 . Numerical results point that injection-locked QCLs show no unstable regime in the locking map while giant modulation bandwidths as large as 200 GHz can be reached with a 10 dB injection level ratio.
En savoir plus

7 En savoir plus

Ultrafast Raman laser mode-locked by nanotubes

Ultrafast Raman laser mode-locked by nanotubes

Mode-locked lasers have been widely deployed in time- resolved studies for nearly 50 years [ 1 ]. While many mode-locking approaches exist, allowing an extensive range of pulse durations and energies to be achieved, passive techniques are particularly attractive because of their inherent simplicity and lower production costs [ 2 ]. Over the past two decades, passively mode-locked fiber lasers have been extensively refined and developed, becoming a commercial success and an indispensible tool in many fields [ 1 , 2 ]. These systems have almost ex- clusively been based on rare-earth-doped gain media [ 1 , 2 ], taking advantage of the rapid technological growth of fiber-based amplifiers, driven largely by the telecom- munications industry. However, such lasers have limited bandwidth, as rare-earth-doped gain fibers have typically narrow gain bandwidth ( ∼few tens nm) [ 1 ].
En savoir plus

4 En savoir plus

Quantum dot based mode locked lasers for optical frequency combs

Quantum dot based mode locked lasers for optical frequency combs

negative voltage is applied to the absorber section of the laser and current is injected into the gain section. For injection currents above the threshold value I th , an optical waveform is allowed to propagate inside the cavity, being amplified in the gain section and attenuated in the absorber. If the waveform includes a sharp temporal feature with enough energy to induce loss saturation at the absorber, the latter will become transparent during a short time interval before loss recovery takes place. This will lead to the formation of a pulse that, propagating into the gain section, will deplete the carrier population of the inverted medium, causing gain saturation. If the absorption recovers faster than the gain and recovery times of both are shorter than the cavity round-trip time, then a window of net amplification is produced at each round-trip and generation of a stable pulse train will eventually occur after a certain transient. The steady-state ML regime resulting from this process is represented in fig. 1.10b. It can be noticed that the width of the net gain window, and hence the pulse duration, is intrinsically governed by the relative dynamics of gain and loss saturation. In particular, if loss saturation and recovery is much faster than that of gain, very short pulses can be achieved. On the other hand, if dynamics in the two sections become comparable, broadened pulses are emitted. Also important is the pulse amplification per round-trip, that will be larger for a lower saturation depth of the gain compared to the absorption one.
En savoir plus

175 En savoir plus

A 1.6-3.2GHz, high phase accuracy quadrature phase locked loop

A 1.6-3.2GHz, high phase accuracy quadrature phase locked loop

For modern monolithic VCOs, there are two principal topologies. The first is a ring oscillator, composed of a ring of inverters with a net inversion around the loop, as shown in Figure 1-2. The frequency is inversely proportional to the propagation delay of each of the individual inverters as well as the number of inverters. To tune the frequency of such an oscillator, the propagation delay of an individual stage can be adjusted by varying the current through it [43], or it can be tuned digitally by switching in a different number of inverters. The maximum oscillation frequency of a ring oscillator can be very high since the propagation delay of a self-loaded inverter is small. In fact, ring oscillators are often used to characterize digital processes for precisely this reason. The current through each of the stages can vary over several orders of magnitude, so ring oscillators can have very wide tuning ranges. With differential signalling, a ring oscillator can be built with four stages by flipping the output of the fourth stage as it is fed back to the input of the first stage. In this configuration, the outputs of any two consecutive stages are in quadrature, with any mismatch in the delay through each of the inverters causing phase error; however, if sinusoidal quadrature signals are required, the ring oscillator output must be filtered.
En savoir plus

124 En savoir plus

InAs/InP quantum dash mode locked lasers for optical communications

InAs/InP quantum dash mode locked lasers for optical communications

144 differences due to a longer propagation round-trip, which explains why the reports on ultra short pulses from single section MLLs almost always corresponded to ultra high repetition frequencies (very short cavity lengths) devices [12], [15], [114]. The value of  was found to be slightly different in both lasers and to decrease with injection current from ~0.2 to ~0.1 rad. Despite these relatively small values of  , pulses cannot be formed due to the wide spectral widths of the laser emission if no dispersion compensation is performed. Indeed, the larger the spectral width the smaller the value of GDD required for pulse generation. This explains the observation of sharp pulses from single section semiconductor lasers only after filtering a few number of modes from the optical spectrum, as reported in [22], [125], [126]. In order to see this, Figure 4-31(b) illustrates the results of simulations showing the simultaneous effects of GDD and number of modes on pulse width for the 890  m laser. A stronger dependence of GDD as the number of modes increases is clearly observed. For a small number of modes, the effect of GDD is less important as the mode phases will almost perfectly fit a straight line in which case the modes interfere constructively; however, as the number of modes increases, the modes will begin interfering out of phase due to accumulated dispersion, therefore affecting pulse generation leading to pulse broadening. At 400 mA, the number of modes at -3dB for this laser is ~ 30 from which a GDD=1.3 ps 2 was measured. From Figure 4-31(b), this yields a very broad intensity profile of ~ 9 ps with very low peak powers (as shown in Figure 4-26(b)). In the case of zero GDD or, equivalently, after external dispersion compensation, pulse widths of ~ 600 fs are attainable, in agreement with the experimental results. In this case the pulse width will always decrease when increasing the number of modes as they will perfectly interfere in phase.
En savoir plus

210 En savoir plus

Beat note stabilization in dual-polarization DFB fiber lasers by an optical phase-locked loop

Beat note stabilization in dual-polarization DFB fiber lasers by an optical phase-locked loop

Laser 10G presents roughly the same pump threshold and output power as laser 1G. An important difference is that the VCO gain is measured to be 0.5 MHz/mA in this case, which is much higher than for sample 1G. We then used a low noise, low gain (1 mA/V) diode driver. We also had to upgrade the mixer and the LO for operation at 10 GHz. Loop filter adjustments then lead to a proportional gain of 35 dB leading to a loop bandwidth of 33 kHz. As in case 1G, the laser beat at 10 GHz can be efficiently captured and locked. The phase noise spectrum is displayed in Fig. 5(c). The close-to-carrier phase noise is limited by the LO, while the intermediate frequency band shows lower phase noise than before, due to the low- noise diode driver. A phase noise plateau is measured at –75 dBc/Hz from 100 Hz to 20 kHz offset from carrier. Finally the tracking range is 4 MHz, which again permits to maintain the beat locked for days, with an instrument-limited 1 Hz measured linewidth.
En savoir plus

7 En savoir plus

rf linewidth reduction in a quantum dot passively mode-locked laser subject to external optical feedback

rf linewidth reduction in a quantum dot passively mode-locked laser subject to external optical feedback

We have also explored the variation in center frequency and RF linewidth as the feedback loop is changed through the optical delay line (Fig. 6). The experimental results demonstrate a similar trend to those observed in QWMLLs under optical external feedback 7 and confirm the numerical simulation result from Avrutin et al 10 in a two-section monolithic MLL under the integer resonant feedback case. The periodicity can be viewed approximately as 1.5-mm (delay time: ~200 ps), which corresponds to the mode-locking frequency of ~5 GHz. It is noted that when approaching the exact resonant condition (Lext=nL), the noise is enhanced and the laser can become unstable with stronger optical feedback. For instance, an increase in the RF linewidth, which is a sign of the noise in the laser cavity, is observed in Fig. 6. This experimental result corroborates the numerical simulation result for an integer resonant case in which it was shown that the laser under near-exactly resonant feedback could follow very specific nonlinear dynamics. 10
En savoir plus

16 En savoir plus

Applications of Delay Locked Loop in frequency synthesizers in analogue circuit.

Applications of Delay Locked Loop in frequency synthesizers in analogue circuit.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignemen[r]

148 En savoir plus

Show all 10000 documents...