Spectrum analyzer

About: Spectrum analyzer is a research topic. Over the lifetime, 12217 publications have been published within this topic receiving 101851 citations.

Passive synthetic arrays

Abstract: This article develops the concept of the passive synthetic array, including its design and implementation, its response to signal and noise, and its overall performance. The only case considered is the ideal case of a constant velocity receiver, a constant bearing narrow‐band source, stationary signal and noise statistics, and single‐path propagation in the plane of the source and receiving synthetic array. It is shown that, in this ideal case, the passive synthetic array is identical to the narrow‐band spectrum analyzer in both implementation and performance, with the total gain determined to a close approximation by the bandwidth of the signal. Considering the processor to be a synthetic array beamformer, however, yields additional information about a detected narrow‐band source because the bearing of the source can be determined if a course or speed change is made by the sensor.

Methods for delay-fault testing in field-programmable gate arrays

Abstract: Systems and methods for delay-fault testing field programmable gate arrays (FPGA's), applicable both for off-line manufacturing and system-level testing, as well as for on-line testing within the framework of the roving self-test area (STARs) approach are described. In one method according to the present invention, two or more paths under test receive a test pattern approximately simultaneously. The two paths are substantially identical and thus should propagate the signal in approximately the same amount of time. An output response analyzer receives the signal from each of the paths and determines the interval between them. The output response analyzer next determines whether a delay fault has occurred based at least in part on the interval. In one embodiment, the output response analyzer comprises an oscillator and a counter. The oscillator generates an oscillating signal during the interval between the test signal propagates through the first path under test and when the test signal propagates through the last path under test.

System and method for measuring the doping level and doping profile of a region in a semiconductor substrate

Abstract: A system for measuring the doping levels of a doped region in a semiconductor substrate, wherein an analyzer beam and a reference beam are generated, the analyzer and reference beams being substantially parallel and spaced apart from each other so that the analyzer and reference beams are non-overlapping. The analyzer beam is focused on a preselected doped region of the substrate and the reference beam is focused on an undoped region of the substrate, the doped region generating a phase shift of the analyzer beam relative to the reference beam corresponding to a level of doping of the doped region of the substrate. A detector detects the phase shift of the analyzer beam relative to the reference beam, and the doping level of the substrate in the preselected doped region is determined from the phase shift. The doping level measuring system may be used to control a semiconductor fabrication process.

Apparatus for generating an enhanced downmix signal, method for generating an enhanced downmix signal and computer program

Abstract: An apparatus for generating an enhanced downmix signal on the basis of a multi-channel microphone signal comprises a spatial analyzer configured to compute a set of spatial cue parameters comprising a direction information describing a direction-of-arrival of a direct sound, a direct sound power information and a diffuse sound power information on the basis of the multi-channel microphone signal. The apparatus also comprises a filter calculator for calculating enhancement filter parameters in dependence on the direction information describing the direction-of-arrival of the direct sound, in dependence on the direct sound power information and in dependence on the diffuse sound power information. The apparatus also comprises a filter for filtering the microphone signal, or a signal derived therefrom, using the enhancement filter parameters, to obtain the enhanced downmix signal.

Method and apparatus for locating pipeline damage

Abstract: Apparatus and method are provided for the location of pipeline damage and medium leak therefrom by acoustical monitoring of the soil about a pipe and recording emission noise by microphone and an amplifier which controls a peak noise indicator. Each measurement point detected by the amplifier is applied to a digital memory to display a histogram showing noise distribution along the pipe. The main frequency of the loudest measurement point is determined, and an octave filter is utilized to determine the frequency characterizing medium leakage to precisely locate the pipeline damage. Bar diagrams may be provided on a viewplate by bands of parallel arrays of light emitting diodes to display noise distribution along the pipeline. A frequency analyzer may transmit from the amplifier to the memory the peak frequency value of each observed frequency band to enable frequency analysis of the loudest measurement point. The apparatus may have a case with a lid defining openings sized for viewing the bar diagrams.