Topic
Spectrum analyzer
About: Spectrum analyzer is a research topic. Over the lifetime, 12217 publications have been published within this topic receiving 101851 citations.
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TL;DR: In this paper, two methods of determination of the Verdet constant (V) for an optically transparent medium are described using the same apparatus in which the intensity of a monochromatic beam of light is modulated by passing it, successively, through a polarizer, the medium under test (contained within a solenoid which carries ac of frequency f in its windings), and an analyzer.
Abstract: Two methods of determination of the Verdet constant (V) for an optically transparent medium are described. These methods use the same apparatus in which the intensity of a monochromatic beam of light is modulated by passing it, successively, through a polarizer, the medium under test (contained within a solenoid which carries ac of frequency f in its windings), and an analyzer. The emergent beam is incident on a detector which produces a steady output voltage Uo for the special conditions of the optical system set for maximum transmittance and, simultaneously, zero modulation. Methods I and II, which were tested by determining V for water for the wavelength 643.3 nm, are based, respectively, on the ratios u1/Uo and u2/Uo, where u1 is the rms value of detector output voltage varying at frequency f and u2 is the corresponding output varying at frequency 2 f. The three mean values of V from method I, method II, and a literature survey agree to within 1%. The standard deviation in the values of V by method I ...
39 citations
Patent•
10 Mar 1988
TL;DR: In this paper, an apparatus for detecting a high frequency artifact contained in an electrocardiogram signal is disclosed, which enables the presence of the high frequency artifacts to be detected with a high precision by extracting high frequency components having a frequency and amplitude equal to or more than a predetermined value within a predetermined time interval.
Abstract: An apparatus for detecting a high frequency artifact contained in an electrocardiogram signal is disclosed, which enables the presence of the high frequency artifact to be detected with a high precision by extracting high frequency components having a frequency and amplitude equal to or more than a predetermined value within a predetermined time interval of the input electrocardiogram signal by converting the high frequency components to pulses, by counting the pulses, and by comparing the counted pulses with the predetermined value. This apparatus is used in connection with, for example, an electrocardiograph, an electrocardiogram analyzer, and the like, and enables precise discrimination between an abnormal electrocardiogram waveform and the high frequency artifact.
39 citations
TL;DR: The ISEE-C plasma wave investigation is designed to provide comprehensive information on interplanetary waveparticle interactions as mentioned in this paper, and three spectrum analyzers with a total of 19 bandpass channels cover the frequency range 0.3 Hz to 100 kHz.
Abstract: The ISEE-C plasma wave investigation is designed to provide comprehensive information on interplanetary wave-particle interactions. Three spectrum analyzers with a total of 19 bandpass channels cover the frequency range 0.3 Hz to 100 kHz. The main analyzer, which uses 16 continuously active amplifiers, gives two complete spectral scans per second in each of 16 filter channels. The instrument sensors include a high-sensitivity magnetic search coil, and electric antennas with effective lengths of 0.6 and 45 m.
39 citations
TL;DR: The adaptation of a commercial large particle analyzer to measure fluorescence and Raman spectra of individual particles at high speeds to enable new applications in biological and chemical analyses is reported on.
Abstract: Flow cytometers designed to analyze large particles are enabling new applications in biology and chemistry. Similarly, flow spectroscopy approaches are extending the capabilities of the flow cytometry platform. Here, we report on the adaptation of a commercial large particle analyzer to measure fluorescence and Raman spectra of individual particles at high speeds. We modified a Union Biometrica COPAS Plus instrument to allow red excitation and optical fiber-based light collection and spectral analysis using a spectrograph and CCD array detector. These modifications did not compromise the ability of the instrument to resolve different sized particles based on their extinction and time of flight signals. The modified instrument has the sensitivity and spectral resolution to measure the fluorescence and Raman signals from individual particles with signal integration times of 10 usec. The high speed spectral analysis of individual particles in flow will enable new applications in biological and chemical analyses.
39 citations
Patent•
24 Feb 1994
TL;DR: In this paper, an electrical parameter analyzer analyzes samples of electrical power by executing program instructions stored on a PCMCIA compatible program card, and a central processing unit including a microprocessor which reads the program card and passes program instructions to an acquisition control processor and an input/output controller, each of which has its own microprocessor.
Abstract: An electrical parameter analyzer analyzes samples of electrical power by executing program instructions stored on a PCMCIA compatible program card. The analyzer has a central processing unit including a microprocessor which reads the program card and passes program instructions to an acquisition control processor and an input/output controller, each of which has its own microprocessor. A series of values for a characteristic parameter of the electrical power are generated by the acquisition control processor, and these values are printed under control of the input/output controller upon request of the central processing unit.
39 citations