Abstract: The present disclosure provides a receiving circuit for adaptive impedance matching and an operating method thereof. The receiving circuit includes: a first amplification module configured to amplify an input signal input from an input end of the first amplification module to generate a first amplified signal; a frequency mixing module, an input end of which is connected to an output end of the first amplification module, and configured to down-convert the first amplified signal to generate a down-converted signal; and a second amplification module, an input end of which is connected to an output end of the frequency mixing module, and configured to amplify the down-converted signal to generate an output signal, wherein the first amplification module includes an active negative feedback structure for providing adaptive impedance matching in a first bandwidth range.

Abstract: A single-temperature-point temperature-sensitivity sensor assumes that all sensitivity lines converge at absolute zero temperature, so during calibration measurement is needed at only one temperature. A sensor output voltage is generated by current from a mirrored current source flowing through a variable resistor. During calibration, the resistance of the variable resistor and the mirror ratio of the mirrored current source are adjusted. An error amplifier compares voltages generated by unit currents generated by unit current sources to adjust the unit current sources and the mirrored current source. Each unit current flows through a grounded-base PNP transistor. A switchable PNP transistor is in parallel with one of the grounded-base PNP transistors and has its base switched on and off to adjust the PNP current for two measurements. The difference between the two measurements is compared to a calibration target to adjust the variable resistor and mirror ratio during calibration at a single temperature.

Abstract: Method and apparatus for generating a dental panoramic image and panoramic camera for photographing teeth, including: determining a frame frequency of a reference detector, and determining frame frequency of a photographing detector; photographing teeth according to the frame frequency of the photographing detector to generate a plurality of images; performing a shift and superposition on the images to generate a first panoramic image; acquiring a fuzzy region in the first panoramic image; and performing a frame frequency adjustment on each row in the fuzzy region to generate a clear image, and fusing the clear image and the first panoramic image to generate a second panoramic image. By using different changing rules of the frame frequency for imaging for each row of the image, both cusps and roots of teeth of the patient may be arranged in a focusing layer, generating a clear image, and improving definition of the panoramic image.

Abstract: A method and apparatus for generating a tooth panoramic image, and a panoramic machine for photographing teeth. The method comprises: determining a frame frequency of a reference detector, and determining a frame frequency of a photographing detector according to the frame frequency of the reference detector; photographing the teeth of a user according to the frame frequency of the photographing detector so as to generate a plurality of images; performing shift superposition on the plurality of images so as to generate a first panoramic image; acquiring a fuzzy region in the first panoramic image; and performing frame frequency adjustment on each row in the fuzzy region so as to form a clear image, and fusing the clear image and the first panoramic image so as to generate a second panoramic image.

Abstract: A low-headroom current driver does not use an op amp or resistor. A sensing transistor having its source connected to a drain of an output transistor senses variations in an output current. The gate, source, and drain voltages of the sensing transistor are mirrored to a sense mirror transistor to control a sense current. The sense current is mirrored to a reference source transistor to generate a mirrored sense current. An error between the mirrored sense current and a fixed reference current is stored as charge on an error-storing capacitor. The stored error charge creates a negative-feedback compensation current that adjusts a gate voltage generated by a feedback-driving transistor. The adjusted gate voltage controls the gate of the output transistor to compensate for the sensed variation in output current. The sensing current is also compensated using a sense-mirror tail transistor connected to the sense mirror transistor.

Abstract: A low-headroom current driver does not use an op amp or resistor. A sensing transistor having its source connected to a drain of an output transistor senses variations in an output current. The gate, source, and drain voltages of the sensing transistor are mirrored to a sense mirror transistor to control a sense current. The sense current is mirrored to a reference source transistor to generate a mirrored sense current. An error between the mirrored sense current and a fixed reference current is stored as charge on an error-storing capacitor. The stored error charge creates a negative-feedback compensation current that adjusts a gate voltage generated by a feedback-driving transistor. The adjusted gate voltage controls the gate of the output transistor to compensate for the sensed variation in output current. The sensing current is also compensated using a sense-mirror tail transistor connected to the sense mirror transistor.

Abstract: An envelope detector receives an input that is an Amplitude-Modulated (AM) or Amplitude-Shift-Keying (ASK) coded signal. Each channel has a sample switch and a diode that charge an internal sampling capacitor. A hold switch connects the internal sampling capacitor to a summing output capacitor or to a post-processing circuit. A reset switch discharges the internal sampling capacitor after each sample. Two or more channels may be time multiplexed to sample alternate cycles of the input, and then their outputs combined by the summing output capacitor or by the post-processing circuit. The diodes may be reversed to detect the negative envelope rather than the positive envelope. Clocks for the switches may be generated from the input, or may be from a separate clock source. Since the sampling window is open for a whole input cycle, the clock source is insensitive to phase error.