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High sensitivity and wide-dynamic-range ontical receiver for 40 Gbit/s optical communication networks

ELECTRONICS LETTERS 2003年第1期39卷 91-92页

作者： Vetury, R Gontijo, I Liu, YZ Krishnamurthy, K Pullela, R Rodwell, MJ GTRAN Inc Newbury Pk CA 91320 USA Univ Calif Santa Barbara Dept Elect & Comp Engn Santa Barbara CA 93106 USA OCP Inc Chatsworth CA 91311 USA

An optical receiver for 40 Gbit/s communication networks demonstrating very high sensitivity without optical amplification has been developed. The receiver comprises an InP-based pin diode and HBT transimpedance amplifier. The receiver achieves a back-to-back sensitivity of -9 dBm and a high dynamic range of 13 dBm, measured using a pseudorandom binary sequence of 2(31)-1 at a bit error rate of 10(-12). These results show the highest sensitivity and widest dynamic range yet reported for 40 Gbit/s optical receivers without optical amplification.

关键词： p-i-n photodiodes InP-based pin diode very high sensitivity III-V semiconductors pseudorandom binary sequence indium compounds 40 Gbit/s optical communication networks Photoelectric devices integrated optoelectronics Integrated optoelectronics binary sequences bit error rate HBT transimpedance amplifier back-to-back sensitivity 40 Gbit/s InP Optical fibre networks Optical communication equipment high dynamic range sensitivity random sequences high sensitivity wide-dynamic-range optical receiver optical fibre networks optical receivers

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ABSOLUTE-TYPE pseudorandom SHAFT ENCODER WITH ANY DESIRED RESOLUTION

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ELECTRONICS LETTERS 1985年第5期21卷 215-216页

作者： PETRIU, E POLYTECH INST TRAIAN VUIA TIMISOARAROMANIA

It is shown how to use a 2n??1 length pseudorandom binary sequence to develop an absolute-type shaft encoder having any t resolution, where 2n??1??1<t<2n??1. The shaft encoder rotating device has only two concen... 详细信息

It is shown how to use a 2n??1 length pseudorandom binary sequence to develop an absolute-type shaft encoder having any t resolution, where 2n??1??1pseudorandom patterns into natural binary code.

关键词： Spatial variables measurement sequential code-conversion method angular measurement binary sequences concentric code track heads reading heads Other digital circuits pseudorandom shaft encoder absolute-type shaft encoder sequential circuits analogue-digital conversion pseudorandom binary sequence code convertors natural binary code

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Design algorithm of all-optical linear feedback shift registers

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2003年第5期57卷 328-332页

作者： Kalyvas, M Yiannopoulos, K Houbavlis, T Avramopoulos, H Natl Tech Univ Athens Sch Elect & Comp Engn GR-15773 Athens Greece

We demonstrate an algorithm for the design and implementation of an all-optical linear feedback shift register (LFSR), based on optically controlled XOR gate and optical shift registers. The algorithm tackles the huge... 详细信息

关键词： all-optical signal processing all-optical gate all-optical shift register semiconductor optical amplifier linear feedback shift register pseudorandom binary sequence

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EFFECT OF PERCEPTION OF MECHANICAL LOADING ON HUMAN RESPIRATORY PATTERN REGULATION

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JOURNAL OF APPLIED PHYSIOLOGY 1995年第1期79卷 83-93页

作者： DAUBENSPECK, JA RHODES, ES DARTMOUTH COLL THAYER SCH ENGNHANOVERNH 03755

We applied external flow resistive (R) and elastic (E) mechanical loads over the entire respiratory cycle to five normal subjects by using a pseudorandom loading protocol. Loads ranged in magnitude from imperceptible (R0/E0) through just perceptible (R1/E1) to large (R2/E2) and resulted in respiratory pattern responses that were due to reflex responses alone (R0/E0) or to a combination of reflex responses and behavioral reactions to the perception of impeded breathing (R1/E1 and R2/E2). Pattern regulation dynamics were estimated from the computed impulse responses of tidal volume and inspiratory and expiratory durations. We anticipated that emergence of behavioral contributions would be marked by increased variability in response strategies and by increased nonlinearity in the observed responses. Regarding the immediate pattern response to loading, there was a tendency for increased qualitative variation across subjects as the load size increased, but the within-subject variability (coefficient of variation) was unaffected. We found no evidence for increased nonlinearity as loads became perceptible. The emergence of behavioral control in some instances seemed to be marked by reduction of complexity of the impulse response to one dominated by the zeroth-order lag, leading to dynamically simpler responses compared to control.

关键词： IMPERCEPTIBLE LOADING RESPONSES pseudorandom binary sequence BREATHING PATTERN REGULATION RESPIRATORY SENSATION BEHAVIORAL CONTROL OF BREATHING

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Rat choice in rapidly changing concurrent schedules

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JOURNAL OF THE EXPERIMENTAL ANALYSIS OF BEHAVIOR 2018年第2期109卷 313-335页

作者： McLean, Anthony P. Grace, Randolph C. Shevchouk, Olesya T. Cording, Jacinta R. Univ Canterbury Christchurch New Zealand Univ Gothenburg Gothenburg Sweden

In two experiments, experimentally naive rats were trained in concurrent variable-interval schedules in which the reinforcer ratios changed daily according to a pseudorandom binary sequence. In Experiment 1, relative response rates showed clear sensitivity to current-session reinforcer ratios, but not to previous sessions' reinforcer ratios. Within sessions, sensitivity to the current session's reinforcement rates increased steadily, and by session end, response ratios approached matching to the current-session reinforcer ratios. Across sessions, sensitivity to the current session's reinforcer ratio decreased with continued exposure to the pseudorandom binary sequence, contrary to expectations based on previous studies demonstrating learning sets. Using a second group of naive rats, Experiment 2 replicated the main results from Experiment 1 and showed that although there were increases over sessions in both changeover rate and response rate during the changeover delay, neither could explain the accompanying reductions in sensitivity. We consider the role of reinforcement history, showing that our results can be simulated using two separate representations, one local and one nonlocal, but a more complex approach will be needed to bring together these results and other history effects such as learning sets and spontaneous recovery.

关键词： concurrent schedules pseudorandom binary sequence matching law sensitivity reinforcement history rats

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KINETICS OF VENTILATION AND GAS-EXCHANGE DURING SUPINE AND UPRIGHT CYCLE EXERCISE

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EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY 1991年第3-4期63卷 300-307页

作者： HUGHSON, RL XING, HC BORKHOFF, C BUTLER, GC 1. Department of Kinesiology University of Waterloo N2L 3G1 Waterloo Ontario Canada

The dynamics of ventilation (V(E)), oxygen uptake (VO2), carbon dioxide output (VCO2), and heart rate (f(c)) were studied in 12 healthy young men during upright and supine exercise. Responses to maximal and to two different types of submaximal exercise tests were contrasted. During incremental exercise to exhaustion, the maximal work rate, VO2max, V(Emax), f(c,max), and ventilatory threshold were all significantly reduced in supine compared to upright exercise (P < 0.01-0.001). Following step increases or decreases in work rate between 25 W and 105 W, both VO2 and VCO2 responded more slowly in supine than upright exercise. Dynamics were also studied in two different pseudorandom binary-sequence (PRBS) exercise tests, with the work rate varying between 25 W and 105 W with either 5-s or 30-s durations of each PRBS unit. In both of these tests, there were no differences caused by body position in the amplitude or phase shifts obtained from Fourier analysis for any observed variable. These data show that the body position alters the dynamic response to the more traditional step increase in work rate, but not during PRBS exercise. It is speculated that the elevation of cardiac output observed with supine exercise in combination with the continuously varying work-rate pattern of the PRBS exercise allowed adequate, perhaps near steady-state, perfusion of the working muscles in these tests, whereas at the onset of a step increase in work rate, greater demands were placed on the mechanisms of blood flow redistribution.

关键词： OXYGEN UPTAKE CARBON DIOXIDE OUTPUT VENTILATION pseudorandom binary sequence FOURIER ANALYSIS

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pseudorandom TESTING TECHNIQUE FOR CHARACTERIZATION OF LOCAL HEMODYNAMIC CONTROL

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PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY 1973年第4期343卷 309-316页

作者： RUBENSTEIN, HJ KENNER, T ONO, K UNIV VIRGINIA DIV BIOMED ENGN CHARLOTTESVILLE VA USA

In order to investigate the low frequency properties of renal and femoral hemodynamic variables, pseudorandom testing techniques were used. The arterial flow of each bed, in separate experiments, was modulated by a low amplitude signal based on a pseudorandom binary sequence (PRBS) generated by digital computer. The cross-correlation functions between input flow and arterial pressure, venous pressure, and venous flow exhibit damped oscillations in all cases. These responses are parameterized in terms of a damping ratio (ζ) and an undamped natural frequency ω n for a second order model. The parameters of the model are dependent upon the state of the bed as defined by mean arterial and venous pressures, mean flow through the bed, resistance, and oxygen consumption. The results of this study offer further insight into the dynamic low frequency autoregulation phenomenon for the renal and femoral beds of the dog.

关键词： Femoral Vascular Impulse Responses Low Frequency Hemodynamics Peripheral Bed Models pseudorandom binary sequence Renal Vascular Impulse Responses

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Characteristics of first and second order kernels of Visually Evoked Potentials elicited by pseudorandom stimulation

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DOCUMENTA OPHTHALMOLOGICA 2004年第2期108卷 157-163页

作者： Nemoto, N Momose, K Kiyosawa, M Mori, H Mochizuki, M Tokyo Med & Dent Univ Grad Sch Dept Ophthalmol & Visual Sci Tokyo Japan Kanagawa Inst Technol Dept Network Engn Kanagawa Japan

The characteristics of the first and the second order kernels of the visually evoked potentials (VEPs) elicited by pseudorandom binary sequence (PRBS) stimuli were investigated. VEPs were recorded from six eyes of four normal volunteers. The effects of stimulus luminance on the latency and amplitude of the first and the second order kernels were determined. The temporal interactions of transient VEPs elicited by single and double pulse stimuli were compared with the first and the second order kernels of the PRBS-VEPs. The correlation coefficient between the logarithm of the stimuli luminance (log I) and VEP amplitude of the first order kernels was 0.45 (p<0.05), and that between log I and P1 latency was -0.62(p<0.005). The second order kernels were not equal to the temporal interactions of the responses. However, the latency of the negative peak of the fourth slice was similar to the temporal interaction to double pulse stimulation with an inter-stimulus interval of 40 ms. An inhibitory component at 40 ms following the first stimulus was detected in the analysis of both PRBS-VEPs second order kernel and transient VEPs. This function may help to increase the frequency of critical flicker fusion in normal subjects.

关键词： binary kernel luminance nonlinearity pseudorandom binary sequence visually evoked potential

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Ventilatory stability to transient CO2 disturbances in hyperoxia and normoxia in awake humans

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JOURNAL OF APPLIED PHYSIOLOGY 1997年第2期83卷 466-476页

作者： Lai, J Bruce, EN UNIV KENTUCKY CTR BIOMED ENGNWENNER GREN LABLEXINGTONKY 40506

Modarreszadeh and Bruce (J. Appl. Physiol. 76: 2765-2775, 1994) proposed that continuous random disturbances in arterial Pco(2) are more likely to elicit ventilatory oscillation patterns that mimic periodic breathing in normoxia than in hyperoxia. To test this hypothesis experimentally, in nine awake humans we applied pseudorandom binary inspired CO2 fraction stimulation in normoxia and hyperoxia to derive the closed-loop and open-loop ventilatory responses to a brief CO2 disturbance in terms of impulse responses and transfer functions. The closed-loop impulse response has a significantly higher peak value [0.143 +/- 0.071 vs. 0.079 +/- 0.034 (SD) ***(-1).0.01 l CO2-1, P = 0.014] and a significantly shorter 50% response duration (42.7 +/- 13.3 vs. 72.3 +/- 27.6 s, P = 0.020) in normoxia than in hyperoxia. Therefore, the ventilatory responses to transient CO2 disturbances are less damped (but generally not oscillatory) in normoxia than in hyperoxia. For the closed-loop transfer function, the gain in normoxia increased significantly (P < 0.0005), while phase delay decreased significantly (P < 0.0005). The gain increased by 108.5, 186.0, and 240.6%, while phase delay decreased by 26.0, 18.1, and 17.3%, at 0.01, 0.03, and 0.05 Hz, respectively. Changes in the same direction were found for the open-loop system. Generally, an oscillatory ventilatory response to a small transient CO2 disturbance is unlikely during wakefulness. However, changes in parameters that lead to additional increases in chemoreflex loop gain are more likely to initiate oscillations in normoxia than in hyperoxia.

关键词： periodic breathing central chemoreflex peripheral chemoreflex closed-loop response open-loop response impulse response transfer function pseudorandom binary sequence

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ADAPTIVE BUFFERING OF BREATH-BY-BREATH VARIATIONS OF END-TIDAL CO2 OF HUMANS

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JOURNAL OF APPLIED PHYSIOLOGY 1993年第5期75卷 2003-2012页

作者： MODARRESZADEH, M KUMP, KS CHIZECK, HJ HUDGEL, DW BRUCE, EN CASE WESTERN RESERVE UNIV DEPT BIOMED ENGNCLEVELANDOH 44106 CASE WESTERN RESERVE UNIV DEPT SYST ENGNCLEVELANDOH 44106 CASE WESTERN RESERVE UNIV DEPT MEDCLEVELANDOH 44106 VET AFFAIRS MED CTR CLEVELANDOH 44106

We have designed and implemented a computer-controlled system that uses an adaptive control algorithm (generalized minimum variance) to buffer the breath-by-breath variations of the end-tidal CO2 fraction (FET(CO2)) that occur spontaneously or are exaggerated in certain experimental protocols (e.g., induced hypoxia, any type of induced variations in the ventilatory pattern). Near the end of each breath, FET(CO2) of the following breath is predicted and the inspired CO2 fraction (FI(CO2)) of the upcoming breath is adjusted to minimize the difference between the predicted and desired FET(CO2) Of the next breath. The one-breath-ahead prediction of FET(CO2) is based on an adaptive autoregressive with exogenous inputs (ARX) model: FET(CO2) of a given breath is related to FI(CO2), FET(CO2) of the previous breath, and inspiratory ventilation. Adequacy of the prediction is demonstrated using data from experiments in which FI(CO2) was varied pseudorandomly in wakefulness and sleep. The algorithm for optimally buffering changes in FET(CO2) is based on the coefficients of the ARX model. We have determined experimentally the frequency range of FET(CO2) variations that can be buffered adequately by our controller, testing both spontaneous variations in FET(CO2) and variations induced by hypoxia in young awake human subjects. The controller is most effective in buffering variations of FET(CO2) in the frequency range of <0.1 cycle/breath. Some potential applications are discussed.

关键词： ARTERIAL CARBON DIOXIDE PARTIAL PRESSURE VARIATIONS ADAPTIVE CONTROLLER SELF-TUNERS pseudorandom binary sequence SLEEP

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