Rise Decay Time Research Articles

Monaural and Binaural Masking Patterns for a Low-Frequency Tone

A tonal masking experiment of the sort pioneered by Wegel and Lane was conducted with both monotic and dichotic stimulation. The forms of the masking patterns under these two conditions of listening were markedly different. The monotic data were similar to the classical data—there was a local minimum in masking at the masker frequency, gradually more masking at adjacent frequencies, and then a gradual, and asymmetric, decline in masking at frequencies more distant from the masker. For the dichotic condition, however, masking was greatest at the masker frequency, and it showed two local minima at about ±10 Hz from the masker before declining gradually for more distant frequencies. These two minima are interpreted as reflecting a kind of time constant in the binaural system, an interpretation that receives support from research on binaural beats. Across signal frequencies, the masking-level differences (MLDs) ranged from about 1 to 11 dB. Masker: 400 Hz, 70 dB SPL, continuously present. Signal: 100-msec duration, 10-msec rise-decay time. Method: Two-interval forced choice with feedback. Listening conditions: Nm-Sm and N0-Sπ.

High- and Low-Frequency Loudness Adaptation

Recent literature [Stockinger and Studebaker, (1968) and Petty, Fraser, and Elliott (1970)] contradicts much of the preexisting data concerning the magnitude and time course of suprathreshold loudness adaptation. A detailed study was undertaken to determine the magnitude of suprathreshold adaptation at 500 and 3000 Hz in six normal-hearing subjects. A controlled period of preadaptation was followed by 7 min of a continuous adapting signal of 70 dB SPL in one ear. The adapting tone was then continued an additional 4 min while a pulsed tone, identical to the pre-adapting conditions (3000 msec, 331/3% duty cycle, 10 msec rise-decay time) was introduced into the comparison ear for perstimulatory dichotic loudness balances. The experimental conditions were (1) adapting tone: 500 Hz; comparison tone: 400 or 3000 Hz; (2) adapting tone: 3000 Hz; comparison tone: 500 or 2000 Hz. Under these heterophonic conditions, adaptation was measured by the method of constant stimuli and repeated with a linear tracking technique. Essentially no adaptation was found at 500 Hz with either test method. At 3000 Hz a minimal decrement in loudness level (less than 5 dB) was obtained. The findings of minimal adaptation at 300 Hz and no adaptation at 500 Hz support the more recent literature indicating little, if any, loudness adaptation when binaural interaction is reduced or eliminated by a heterophonic procedure.

Rapid acquisition of an auditory localization discrimination by rats.

Acquisition of a sound localization discrimination by rats was investigated. Two loudspeakers were located outside an experimental enclosure containing two levers and a dipper feeder. In the same-side condition, responses on the lever nearest the sound-producing speaker were reinforced. Animals in this condition acquired the discrimination rapidly, generally within the first session. In the opposite-side condition, responses on the lever furthest from the sound-producing speaker were reinforced. Acquisition for animals in this condition began below the chance level (50% correct responses) and took on the order of 10 sessions to approach the final, high level. The course of acquisition in both cases appeared to depend upon an initial tendency of rats to respond on the lever nearest the source of sound in this situation. The rise-decay time of the 4-kHz tone burst signal clearly affected the performance level reached. It did not, however, affect the rate at which the discrimination was acquired.

Early components of the averaged electroencephalic response in relation to rise-decay time and duration of pure tones.

Early components of the averaged electroencephalic response (AER) to auditory stimuli were elicited in 10 normal-hearing subjects. Stimuli were 1000-Hz tones having rise-decay times of 5, 10, and 2...

Triplet-triplet absorption and energy transfer from high triplet states

Abstract A simple method for determining of triplet-triplet extinction coefficients which is based on the non-linear effect in transitions between three levels of Jablonsky diagram has been suggested. Triplet concentrations were obtained from the expression N T st = C 0 (1 - τ r /τ d ), where τ r and τ d are the rise time and decay time of triplet concentrations respectively, C 0 is the ground state concentration of solute molecules. The triplet-triplet extinction coefficients, ϵ T , for 15 aromatic molecules have been measured including carbazole, diphenylamine, fluorene, benzidine, byphenyl, chrysene, coronene and some others. The results obtained have been used for evaluating the solute high triplet level energy escape efficiency β to solvent triplet level (solvent: glassy toluene at 77°K). The absorption of every hundred light quanta in triplet-triplet absorption band of aromatic solute results in 2–18 acts of big portion energy transfer into solvent. The observed differences in β values are tentatively explained in terms of distinct high triplet level lifetimes for various aromatic molecules.

Effects of rate of signal rise and decay on reaction time to the onset and offset of acoustic stimuli

This study assessed the effects of variations in signal rise-decay time on response latencies to the onset and cessation of a 1,000-Hz tone. Onset and offset reactions were combined factorially with five rates of signal rise-decay (0.5, 5, 25, 100, and 250 msec) to produce a total of 10 experimental conditions. Offset RTs were significantly longer than onset RTs when the rise-decay time of the tone was 250 msec. Disparities in speed of reaction to tone onset and cessation were negligible at the remaining rates of signal rise-decay.

Unitary Components in the Activation of Clarke's Column Neurones

AbstractIn response to muscle stretch unitary EPSPs were recorded from group I activated dorsal spinocerebellar tract (DSCT) neurones. The size of the different unitary EPSP varied appreciably, the largest was about 5 mV. The rise time and decay times of the unitary EPSPs varied only between 0.2–1 msec and 1–3 msec respectively. The estimate of the number of primary afferent fibres converging on to each second order neurone ranged from 12 to 16. The distribution of amplitudes of individual unitary EPSPs was symmetrical with a coefficient of variation as low as 0.10. This suggests that a large number of quanta are released by each impulse in the primary afferent fibres.

Response of aequorin bioluminescence to rapid changes in calcium concentration.

Aequorin is a protein which emits light after reaction with calcium. The rise time and decay time of luminescence are in the millisecond region, making aequorin a useful detector of calcium in biological systems.

Spectral Energy Requirements and Adjacent-Channel Crosstalk in CAS

Four-frequency channels avoid the prior slot interference that handicaps single-frequency collision avoidance systems of equal message-slot capacity. Crosstalk between adjacent frequency channels is adequately limited If the receiver response to adjacent-channel signals is attenuated at least 52 dB. With 5-MHz channel separation, 48-dB crosstalk rejection was achieved in a test receiver by restricting the RF pulse rise time and decay time to 0.2 μs minimum. Crosstalk resulting from biphase modulation can be effectively attenuated by limiting the minimum envelope transition time to 0.2 μs. The effect of pulse rise time and decay time on the energy density spectrum is discussed.

Energetic Solar Flare X-Rays Observed by Satellite and Their Correlation with Solar Radio and Energetic Particle Emission

view Abstract Citations (114) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Energetic Solar Flare X-Rays Observed by Satellite and Their Correlation with Solar Radio and Energetic Particle Emission Arnoldy, R. L. ; Kane, S. R. ; Winckler, J. R. Abstract Ionization chambers aboard the OGO-A and OGO-B spacecrafts with a response window for X-rays between 10 and 50 keY have accumulated more than 6000 hours of operation in space outside Earth's magnetosphere. Approximately thirty solar flare X-ray bursts have been detected between September 5, 1964, and June 20, 1966. These energetic X-ray bursts have been correlated with 3- and 10-cm solar radio emission and solar-flare electron and proton events measured in space. A proportionality is observed between the time-integrated X-ray and radio fluxes, and for a given flare the rise time, decay time, and total duration of the radio and X-ray bursts are similar. Exponential time constants between 1 and 10 mm characterize the decay. All 3- or 10-cm radio bursts greater than 80 flux units are accompanied by an X-ray event greater than 3 X 1O~ ergs cm~ sec', and the probability of detecting an X-ray event is negligible unless the radio spectrum includes the centrimetric range of wave- lengths. All but three of the X-ray events were correlated with SWF ionospheric disturbances. A number of large flare events occurred in which all of the energetic processes were observed; namely, solar protons, solar electrons, energetic bremsstrahlung, and high-frequency radio emission. In comparing energetic X-rays with solar particle emission the best correlation seems to exist with the solar electron events ob- served in space. Many solar proton events occurred without a detectable burst of energetic X-rays. It is shown that the results are consistent with a source in the flare region consisting of an active volume in a magnetic field containing hot or energetic electrons which lose energy predominantly by collisions with a much cooler gas and produce X-rays by bremsstrahlung. The similarity of decay and proportion- ality between the X-rays and microwaves suggests that the same electrons might produce both emissions About 5 X 10~ joules m~ (c/s)1 of microwave energy at Earth are required per electron at the Sun on the average. Physically acceptable choices of electron energy, collisional limited lifetime, and mag- netic field strength exist such that, with the assumption of synchrotron emission for the microwave radiation and bremsstrahlung for the X-rays, the observed proportionality between the two can be met A thermal source for the radio emission cannot, however, be excluded Publication: The Astrophysical Journal Pub Date: February 1968 DOI: 10.1086/149470 Bibcode: 1968ApJ...151..711A full text sources ADS |

The observation of 10–50 KeV solar flare X-rays by the OGO satellites and their correlation with solar radio and energetic particle emission

More than 70 cases have been observed of energetic solar flare X-ray bursts by large ionization chambers on the OGO satellites in space. The ionization chambers have an energy range between 10 and 50 KeV for X-rays and are also sensitive to solar protons and electrons. A study has been made of the X-ray microwave relationship, and it is found that the total energy released in the form of X-rays between 10 and 50 KeV is approximately proportional to the peak or total energy simultaneously released in the form of microwave emission. For a given burst the rise time, decay time and total duration are similar for the 10–50 KeV X-rays and the 3 to 10 cm radio emission. Roughly exponential decay phases are observed for both emissions with time constants between 1 and 10 min. All 3 or 10 cm radio bursts with peak intensity greater than 80 solar flux units are accompanied by an X-ray burst greater than 3 × 10−7 ergs cm−2 sec−1 peak intensity. The probability of detecting such X-ray events is low unless the radio spectrum extends into the centimetric range of wavelengths. The best correlation between cm-λ and energetic X-rays is observed for the first event in a flare. Subsequent structure and second bursts may not correspond even when the radio emission is rich in the microwave component. The mechanism for the energetic X-rays is shown to be bremsstrahlung probably of fast electrons on a cooler plasma. If the radio emission is assumed to be synchrotron radiation then a relationship is developed between density and magnetic field which meets the observed quantitative results. One finds, on the average, that 5 × 10−54 joules m−2 (CPS)−1 of microwave energy at the Earth are required per electron at the Sun to provide the radio emission for the various events.A strong correlation between interplanetary solar flare electrons observed by satellite and X-ray bursts is shown to exist. This correlation is weak for solar proton events. One may infer a strong propagation asymmetry for solar flare electrons along the spiral interplanetary magnetic field.

Silicon-Controlled Rectifier Circuitry for Producing Pulsed Magnetic Fields

A switching circuit using a high powr silicon-controlled rectifier to discharge a high energy (5 kJ), low voltage (450 V) capacitor bank into pulse coils immersed in liquid helium is described. A free-wheeling diode assures that the pulses remain unidirectional. The circuit has successfully operated with inductance-resistance-capacitance (LRC) combinations yielding pulses having rise times τR and decay times τD in the ranges 0.80 msec ≤τR≤0.25 sec and 2.2 msec ≤τD≤1.2 sec, respectively. Another SCR is used to shunt unwanted capacitor energy to an auxiliary circuit at any desired time during the pulse duration. This function is used to protect the pulse coils from overheating and to conserve liquid helium. The use of special, fixed-geometry copper coils is described which enables one to obtain initial rates of change of the applied magnetic field Ḣ0 which varied over many orders of magnitude (102<Ḣ0<108 Oe/sec). The circuit, while generally useful in most solid-state studies requiring pulsed-magnetic fields, was used to study flux-jumping, rate effects, and critical currents in tubes and wires made of type II superconducting materials. Some of these experiments are described.

Fundamental problems in adaptation measurement

Basic principles of the measurement of adaptation were studied from following three points of view; the time course, relation between adaptation and the length of the duration of comparison tones and the adaptation for the interrupted tones.By using the procedure which was introduced by the authors (Loudness balance between continuous and interrupted tones), the time course and theptation of the development of adaptation were measured. Test tones were 1000 cps pure tones with the intensity ranging from 10to 60 db (SL) and the comparison tones were interrupted tones with the same frequency. The comparison tone was interrupted with the repetition period of 2500ms, duty cycle of 70%o and the rise and fall decay time of 25ms. The intensity of the comparison tone was regulated by the subject withBekesy type attenuator. In the result, it was concluded that the development of adaptation was very rapid, but decelerative. In the initial stage of the stimulation, it was so rapid that it could not be recorded by the Bekesy attenuation with speed of 2db/sec. Though the time required to reach the asymptote varied depending upon the intensity of the test tone, it usually ranged trom 30 to 90 seconds.For the second purpose, comparion tones with the length of duration ranging from 10 to 45 seconds were used in the dichotic balance procedure.They were given in two different fashions of tracking and descending. Two conclusions were drawn from the results. First, the longer the duration of the comparison tone, the lesser the adaptation measured were. Second, the values of the measured adaptation were strongly dependent upon the manner of the comparison stimulation, namely, about 25 db difference was observed between the values obtained by tracking and descending fashion.The authors supposed that the main cause of this discrepancy was the shifted loudness function due to the adaptation.Another two different experiments were done for the third purpose. By using the different kind of interrupted tones as the comparison stimuli in the authors' procedure, the influences of the duty cycle and the repetition period of the comparison stimulus upon the measured adaptation were studied, whereby no clear influence was observed.Second, the adaptation for the interrupted tone was measured by asymptotic balance procedure. Two test tones which were interupted in the following manner were adopted. (1) Repetition period of 2500 ms and the duty cycle of 70%. (2) Repetition period of 100ms and the duty cycle of 70%. In the results, no adaptation was observed.In conclusion, the authors stressed that the development of the perstimulatory adaptation was so rapid that the comparison stimulus with 10 seconds or more duration shold not be used in the adaptation measurement. If such a stimulus with long duration was adopted in the adaptation measurement as a comparison stimulus, the values obtained were strongly dependent upon the stimulation manner of the comparison ear. The authors recommended the use of the interrupted tone for the comparison stimulus, whereby no adaptation for the comparison ear would be expected.

Studies on perstimulatory loudness adaptation

1. Actual process of the development of lou-dness decrease (perstimulatory loudness adaptation)was measured and recorded by means of Bekesy audiometry.2. Loudness decrease occured abruptly imme-diately after the stimulation began, and rapid but negatively accelerated development followed, Lou-dness decrease was mainly observed in the firs tseveral seconds but asymptote was reached about 1 to 3 minutes later.3. The amount of loudness decrease became greater as a test tone was intensified and it attai-ned a maximum amount at 80db of suprathreshold level. But it seemed to be almost constant bet-ween 70db and 90db and it showed a tendency of decrease if a test tone was intensified still greater.4. The amount of loudness decrease was lar-ger at 1000cps and higher frequency tone than 500cps. Even if the different rates of loudness growth at these frequencies were corrected, this tendency was still maintained.5. It seemed that there was no relationshipbetween the amount of loudness decrease and a rise decay time or a duty cycle if the comparison tone was completely interrupted.6. The ear which was adapted to the tone of 1000cps was thought to be adapted to the tone of 2000cps too.

Perstimulatory adaption by amplitude modulated tone in normal subject

The present paper was concerned with the observations of perstimulatory auditory adaptation in the normal ear using the amplitude modulated tone. A pure tone, with a frequency of 1000cps in intensity of 50db above subjective threshold, was presented to the ear in different patterns as follows:(1) continuous presentation.(2) amplitude modulated presentations in the form of trapezoidal change, with modulation rate from 2db to 30db and modulation frequency of 4cps.(3) interrupted presentation with a repitition period of 250msec, a duty cycle of 50%, and a rise-decay time of 40msec.Perstimulatory auditory adaptation was measured by means of the binaural balancing technique with the matching time of 15sec.The following results were obtained:(1) An amount of perstimulatory auditory adaptation after 5 minutes was maximum in the contiuous tone, minimum in the interrupted, and intermediate in the amplitude modulated.Particularly, in the stimulation of the amplitude modulated tone, the degree of adaptation loss decreased with the increase of amplitude modulation rate.(2) Most of the test ears showed no adaptation loss for amplitude modulated tones with amplitude modulation rate of more than 10db.It was suggested that auditory stimulus in periodic fluctuation of intensity could bring about disappearance or decrease of perstimulatory adaptation in the normal ear as well as in the interrpted tone.

Pressure Pulses of Small Explosions at Great Depths in the Ocean

In several underwater-explosion studies during the past 15 years, small charges have been fired at ocean depths as great as 3 miles and pressures recorded nearly vertically above the charge so that refraction and scattering effects were negligible. In these tests, the charge weights varied from several hundredths of a pound to as much as 10 lb. The instrumentation in many cases was capable of reproducing wide-band response from a few cycles per second up to as much as 50 kc/sec. An unclassified sample of these numerous data has been analyzed in detail. The variables considered include shock-wave rise time, peak pressure, and decay time, as well as bubble-pulse critical pressures and times. The results permit an extension of the existing semiempirical formulas by an order of magnitude in many cases. The most significant changes in the equations involve the smallest charges at the greatest depths and distances from the pressure gauges. The reduced distance parameter R/W12 is extended from Arons (1954) limit of about 2000 to the order of 30 000.

On the Limits of Binaural Interaction

Deatherage, in 1961, found that his observers could obtain a fused and unitary image when the stimuli to the ears were clicks of different frequency content. When the frequency difference was large, however, the observers obtained two click images of different pitch that could be independently brought to the median plane of the head. The present experiments are an extension of that work. In one experiment, 4 different clicks were paired with each of 5 tone bursts. A centering task was performed with these stimuli at one sound-pressure level and at one sensation level. In a second experiment, 2 clicks were paired with each of 2 tone bursts under several values of rise-decay time for the tone bursts. The interaural-time differences required for a centered image show interesting relations to level, click-frequency, burst-frequency, and rise decay time. These results are discussed in terms of the kinds of operations that take place in peripheral encoding and in central processing. [Work supported by a contract between the U. S. Office of Naval Research and TRACOR, Inc.]

Switch-On Transients in p-n Junctions

The transient response of p-n junctions when switched-on in the forward direction is analyzed in this paper. This transient is complimentary to that analyzed by Lax and Neustadter and by Gossick. When a p-n junction is switched on in the forward direction, nonideal switching characteristics are produced—the transient voltage across the device has finite rise time and decay time. This transient appears capacitive at small signals and inductive at large signals. These nonideal switching characteristics have been explained by the present analysis. Excellent agreement is obtained between theory and experiments for an example diode (1N91). The basis for this analysis is the inclusion of the voltage drop across the bulk material of the base region. In other words, the effects of conductivity modulation are analyzed and added to the junction voltage. It is found that nearly ideal switching characteristics can be obtained if the applied signal is approximately I0, which is given by the intersection of the quiescent base-resistance Rir on the diode dc characteristic.

Effects of Spectral Components, Duration, and Rise Time of Sound on Perceived Noise Level

Laboratory studies were undertaken: (1) to validate, if possible, equal noisiness contours for bands of noise and to extend the range of these contours to higher sound frequencies; (2) to determine the effects of the presence of intense pure-tone components in wide-band noise upon judgments of loudness and noisiness; and (3) to equate the effects of rise time, duration, and decay time of a sound upon its judged noisiness. The data indicate that: (1) Presently published equal-noisiness contours have the proper shape, or nearly so, up to about 6000 cps. An extension of the contours is proposed for use with sounds having higher frequency components. (2) The presence of strong pure-tone components in a background of broad-band noise has a much more dramatic effect on judged noisiness than judged loudness. (3) It appears, from a preliminary study, that the trading relation between over-all duration (212 to 20 sec) and peak sound-pressure level, keeping rise- and decay-time ratios constant is fairly well represented by the “equal energy” rule—i.e., halving the total duration reduces judged noisiness to the same degree as a 3-dB reduction in sound-pressure level. The relation of these findings to procedures for the calculation of perceived noise level is discussed. [This work was jointly supported by the National Aeronautics and Space Administration and by the Federal Aviation Agency, under Contract NASr-58.]

A single-element light amplifier using sintered cadium selenide

The use of photoconductive sintered cadium selenide as the control element in a light amplifier offers the possibility of improved gain and speed of response. Such a single element light amplifier has been made and tested. The results show that moderate gains with high output luminance are possible with speeds in the range of moving pictures. Very high gains are possible if slow response can be tolerated. Measurements were made over a range of operating frequencies and for various input levels. Data on rise time, decay time and gain for tungsten-light input are given in curve form. From these curves the operating range and input-output light levels can be determined for picture reproduction.