摘要:
Provided is a voltage-controlled oscillator (VCO) using a current feedback network for use in a wireless communication terminal. The voltage-controlled oscillator has high input impedance and low output impedance, so that a degree of isolation from the external load is excellent, thereby preventing degradation of the Q-factor by the load in overall oscillation circuit. In the voltage-controlled oscillator of the present invention, an LC resonator is provided to generate positive feedback, and negative resistance may be obtained at a wider frequency range by tuning a varactor of the LC resonator. And a boosting inductor is inserted into the positive feedback loop to have a greater negative resistance, therefore it is possible to prevent a problem in which the oscillation does not occur due to the parasitic resistance components generated during circuit fabrication.
摘要:
There is provided a feedback amplifier capable of easily controlling its dynamic range without a separate gain control signal generation circuit. The feedback amplifier includes an input terminal detecting an input voltage from input current, a feedback amplification unit amplifying the input voltage to generate an output signal, and an output terminal outputting a signal amplified by the feedback amplification unit. The feedback amplification unit includes a feedback circuit unit including a feedback resistor located between the input terminal and the output terminal, and a feedback transistor connected in parallel to the feedback resistor; and a bias circuit unit supplying a predetermined bias voltage to the feedback transistor of the feedback circuit unit and merged in the feedback amplification unit.
摘要:
Systems and methods for real-time tracking of photoacoustic sensing are provided. In one aspect, a method for performing in vivo analysis of a subject is provided. The method includes directing an electromagnetic excitation toward a subject to be analyzed, and acquiring, with an ultrasound probe, data about resultant waves caused by the electromagnetic excitation. The method also includes processing the acquired data to extract information related to properties of tissues in the subject, and comparing the information related to the properties of tissues in the subject using a set of criteria. The method also includes generating a report about a condition of the subject based on the comparison of the information related to properties of the tissues in the subject.
摘要:
An autofocusing endoscope includes an objective lens, a relay optical system arranged to relay an image between the objective lens and a proximal end of the autofocusing endoscope, an optical fiber arranged with a distal end proximate the objective lens, a light source arranged to couple light into the optical fiber, an optical detection system arranged to receive and detect light from the optical fiber, and a data processor constructed to communicate with the optical detection system while in operation. The data processor is configured to determine a distance of a surface to be imaged through the objective lens and provide instructions for adjusting a focus of the autofocusing endoscope of the surface.
摘要:
The present invention relates to an improved pillar anchor and a method for manufacturing the same. According to the pillar anchor of the present invention described as above and the method for manufacturing the same, the rims of the pair of separated base plates abut each other, so that the surface in contact with the belt is formed in a “C”-shape. Thus, it is simple to manufacture the pillar anchor of the present invention, and moreover, the number of processes needed for manufacture is reduced. In addition, since the inner peripheral surfaces of the belt insertion holes around which the belt is wound are generally formed of only a steel plate, the friction coefficient between the belt and the inner peripheral surfaces of the belt insertion holes is reduced. Accordingly, when the belt is subjected to tension, damage caused from wear and tear of the belt due to the friction between the belt and the inner peripheral surfaces of the belt insertion holes is effectively reduced. Moreover, the belt can smoothly moves on the inner peripheral surfaces of the belt insertion holes.
摘要:
A method of preparing a composite of organic and inorganic compounds includes the steps of reacting a mixed solution of a metal alkoxide and a silicon-containing compound with a catalyst to produce an alcogel of a metal oxide or a complex metal oxide. The metal alkoxide is prepared by reacting at least one metal with an alcohol and the mixed solution is prepared by mixing the metal alkoxide with the silicon-containing compound. An alcogel is produced from the reacting step and alcohol is impregnated within the inorganic oxide lattice structure of the alcogel. Furthermore, the method of preparing a composite of an organic and an inorganic compound includes the steps of centrifuging the alcogel to separate any alcohol from the alcogel to form a gel, adding an organic monomer the gel and polymerizing the organic monomer in-situ to form an organic polymer. The resulting composite has characteristics of both the parent organic and inorganic compounds.
摘要:
Systems and methods for real-time tracking of photoacoustic sensing are provided. In one aspect, a method for performing in vivo analysis of a subject is provided. The method includes directing an electromagnetic excitation toward a subject to be analyzed, and acquiring, with an ultrasound probe, data about resultant waves caused by the electromagnetic excitation. The method also includes processing the acquired data to extract information related to properties of tissues in the subject, and comparing the information related to the properties of tissues in the subject using a set of criteria. The method also includes generating a report about a condition of the subject based on the comparison of the information related to properties of the tissues in the subject.
摘要:
Provided are bipolar transistor, BiCMOS device and method of fabricating thereof, in which an existing sub-collector disposed beneath a collector of a SiGe HBT is removed and a collector plug disposed at a lateral side of the collector is approached to a base when fabricating a Si-based very high-speed device, whereby it is possible to fabricate the SiGe HBT and an SOI CMOS on a single substrate, reduce the size of the device and the number of masks to be used, and implement the device of high density, low power consumption, and wideband performance.
摘要:
Provided is a low-reference-current generator that includes a circuit employing two feedback loops enabling it to operate even at a low voltage, has a high power supply rejection ratio (PSRR) to control power supply noise, and simply forms a voltage without a voltage-to-current converter used in a conventional general reference current generator. The reference current generator includes: a first voltage generator receiving a predetermined current and generating a first voltage that decreases as temperature increases; a second voltage generator generating a second voltage that increases as temperature increases; a first current generator generating a first current corresponding to the first voltage; a second current generator generating a second current corresponding to the second voltage; and a reference current generator receiving the first current and the second current and generating a reference current that is the sum of the first current and the second current.
摘要:
A method for calibrating a Fourier domain optical coherence tomography system includes receiving spectral data from an optical detector comprising a linear array of detector elements, each detector element having a position labeled n, wherein detected light was wavelength-dispersed across the linear array of detector elements; determining parameters of a preselected functional relationship between wave number, kn, corresponding to detector element n as a function of optical detector element n based on the spectral data; further receiving subsequent spectral data subsequent to the first-mentioned receiving, wherein detected light was wavelength-dispersed across the linear array of detector elements; converting the subsequent spectral data using the preselected functional relationship between wave number kn and optical detector element n to obtain converted spectral data; and performing an inverse Fourier transform of the converted spectral data to obtain a depth profile.