Abstract: Apparatus for defining a step-by-step path through pixels located at the intersections of rectilinear coordinates that lie between boundaries that cross one set of coordinates. The respective distances of each of a pattern of pixels from one boundary and the distance between boundaries as well as the direction of the last step in the path are applied to a ROM to determine whether the next step is along one type of coordinate or the other or along a diagonal.

Abstract: A high-efficiency programmable power supply including a linear regulator and a switching pre-regulator. The switching pre-regulator monitors the voltage drop across the series pass regulator pass transistor and maintains a predetermined voltage drop thereacross. The programmable power supply output voltage is varied according to a digital signal applied to the linear regulator. The switching pre-regulator, in providing a generally constant voltage drop across the linear regulator pass transistor, increases efficiency of the power supply by reducing excess voltage which appears at the input of the linear series pass regulator to a minimum level below which the linear regulator can operate. Therefore, the power supply according to the present invention maintains high efficiency over a wide range of selectively programmed output voltages.

Abstract: Apparatus for deriving signals indicating a condition of tissue within an area by launching spaced supersonic pulses into a body under examination and detecting the power of supersonic waves scattered from locations along a plurality of known paths. Gain control elements are provided for compensating for changes in amplitude of the scattered supersonic waves resulting from their passage through blood or tissue, the increased attenuation with frequency of the spectrum of the launched pulses and the focussing of the launched pulses. Compensation for ring-down and the attenuation of the chest wall is also provided.

Abstract: A memory means is provided which is adapted to be mounted integral with the transducer element used in a transducer system. The memory may store nonlinearity error information or other information concerning errors in the positioning or scan control for the particular transducer, which information may be utilized by the transducer system to compensate for such errors. The memory may also be utilized to store selected information concerning the measured output characteristics of the transducer element which may be utilized by the transducer system to assure that a desired output level is achieved from the transducer element or that the output otherwise is in conformance with that desired. One or more bytes may be provided in the memory which may be utilized to inhibit use of the associated transducer element for particular fields of use or classes of service.

Abstract: A medical Doppler ultrasound imaging system with improved filtering to separate blood flow information from clutter due to heart wall and vessel motion. In combination with a clutter rejection filter and velocity determination system as in the prior art, a velocity sample rejection system implements a velocity-dependent (i.e., frequency-dependent) threshold for rejecting velocity values, or samples, based on too weak echoes. That is, the acceptance/rejection threshold is a function of frequency. Optimally, the shape of the velocity-dependent thresholding function closely matches that of the attenuation transfer function of the clutter rejection filter. Thuys, for low velocity samples (corresponding to low Doppler frequency shifts), the rejection threshold is substantially lower than it is for high velocity samples. The rejection level increases monotonically as the signal deviates from the I.F.

Abstract: An acoustic damper for substantially reducing the reverberation echoes at the junction between an acoustic signal propagating fluid and a material having an acoustic impedance substantially different from that of the fluid. The damper, which is particularly adapted for use in ultrasonic transducers, is formed of a material having an acoustic impedance which substantially matches the acoustic impedance of the fluid, such material preferably being a foam plastic material having sufficient hardness to be acoustically stable. For preferred embodiments, the damper is formed of a laminate of the layer described above and a second layer of a material which provides high acoustic attenuation, such as cork material.

Abstract: A spectrometer including a source of light, a slit member along the path of the light emitted from the source, a holographic, concave grating in the path of the light passing through the slit member, and a photodetector in the path of the diffracted light reflected from the grating. The photodetector is positioned substantially along the portion of the primary horizontal focal curve of the grating where it is intersected three times by a vertical focal curve of the grating. The three intersections being on the same side of the normal vector to the grating and two of the intersecting points being the positions of the laser used to form the grating.

Abstract: A multi-element optical detector having a planar array of detector elements is focused at the focal plane of an optical spectrometer by placing the detector with the detecting surface of the array facing the optical spectrometer and being substantially perpendicular to the axis of the path of the light from the optical spectra to the focal plane. Relative movement is provided between the detector and the focal plane along said axis so that the detector array is placed at several different positions with respect to the focal plane. At each position the output values of the detector elements of the array are measured and the second difference of the output values is determined by the equation (-F1+2.times.F2-F3), where F1, F2, and F3 are the output values of three of the elements. The optical detector is placed at the position which provides the maximum value of the second difference, which is the position of the focal plane.

Abstract: A mixture of fluorescently-excitable amino acid derivatives suitable for use in quantitative amino acid analysis is provided in which primary amino acids are present as derivatives of a first reagent and secondary amino acids are present as derivatives of a second different reagent. The process for preparing the mixture comprises the steps of derivatization of the primary amino acids of an amino acid sample with ortho-phthalaldehyde (OPA) and of derivatization of the secondary amino acids of the sample with fluorenylmethylchloroformate (FMOC) in the presence of acetonitrile. The mixture can be obtained automatically and is highly suitable for fast analysis by reversed-phase liquid chromatography.

Abstract: The nitrogen-selectivity of an atomic emission detection system is enhanced by use, as the reagent gas, of a single gas or a mixture of gas components containing oxygen and hydrogen in an oxygen/hydrogen molar ratio of about 1:10 to 10:1.

Abstract: The present system employs a high speed digital signal processor which is programmed to generate pairs of digitized waveforms, each pair representing a pair of different frequencies in response to coded input signals. Each pair of different digitized waveforms, when converted and combined into an analog signal, represents a "tone pair" as used in major telephone systems. The tone pairs are transmitted through an anti-aliasing filter circuit and therefrom through amplification circuitry to a tone pair decoder of the type used in major telephone systems. At the tone pair decoder the tone pair signals are reconverted into binary signals. The binary signals from the tone pair decoder are transmitted to a data processor in the system under test, whereat they may or may not be further decoded. Ultimately the binary signals are compared with the coded input signals originally sent.

Abstract: Two transistors, the emitter of the first joined to the collector of the second via a resistor and two bases joined by an element such as a diode. When the input signal applied to the base electrode of the first transistor is less than a given value, neither transistor conducts; when it exceeds a second value close to this given value, substantially constant voltages develop across the diode and resistor, respectively, and the two transistors conduct a constant current.