Abstract:
A microwave imaging apparatus and method is provided to improve the accuracy of measurement data by reducing the interference between channels. A microwave imaging apparatus comprises a photoelectric converting device(310), an electric-photo converting unit(320), a transceiver(134b-134p) and control / treatment unit. The electric-photo converting device converts the oscillator signal into the optical signal. The electric-photo converting device converts the optical signal from the photoelectric converting device into the oscillator signal. The transceiver converts the radio frequency signal which passes through the imaging object by using the oscillator signal transformed with the electric-photo converting device into the IF(Intermediate Frequency) signal. A control/process unit process an intermediate frequency signal transformed with transceiver.
Abstract:
1. 청구범위에 기재된 발명이 속하는 기술분야 본 발명은 스퓨리어스 특성의 개선을 위한 직접디지털주파수합성기 구동 위상잠금루프 주파수합성 장치 및 그 방법에 관한 것임. 2. 발명이 해결하려고 하는 기술적 과제 본 발명은 직접디지털주파수합성기(DDS: Direct Digital Synthesizer)에서 발생하는 스퓨리어스 신호를, 위상잠금루프(PLL: Phase Locked Loop) 주파수합성기의 출력신호를 이용하여 제거함으로써, 위상잡음 특성, 스퓨리어스 특성, 정착시간 (settling time) 및 주파수분해능 등을 향상시킬 수 있는, 스퓨리어스 특성의 개선을 위한 DDS 구동 PLL주파수합성 장치 및 그 방법을 제공하는데 그 목적이 있음. 3. 발명의 해결 방법의 요지 본 발명은, 직접디지털주파수합성기(DDS) 구동 위상잠금루프(PLL) 주파수합성 장치에 있어서, 외부로부터 입력되는 기준신호를 구동신호로 하여 소정의 주파수를 갖는 신호를 생성하기 위한 직접 디지털 주파수합성 수단; 상기 직접 디지털 주파수합성 수단의 출력신호를 입력신호로 하여 소정의 고주파신호를 생성하기 위한 PLL 주파수 합성 수단; 상기 PLL 주파수 합성 수단의 고주파 출력신호를 동위상의 두 개의 신호로 전력분배하기 위한 제 1 전력분배 수단; 상기 제 1 전력분배 수단에 의하여 분배된 신호 중 어느 하나의 신호를 다시 동위상의 두 개의 신호로 전력분배하기 위한 제 2 전력분배 수단; 상기 제 2 전력분배 수단의 출력신호 중 어느 하나의 신호를 시간지연시키기 위한 시간지연 수단; 상기 제 2 전력분배 수단의 출력신호 중 다른 하나의 신호의 위상을 반전시키고, 신호 크기를 조절하기 위한 위상변환 및 가변감쇠 수단; 상기 시간지연 수단의 출력신호와 상기 위상변환 및 가변감쇠 수단의 출력신호를 합성하여, 상기 PLL 주파수 합성 수단의 출력신호에 포함되어 있는 스퓨리어스신호와 위상잡음신호를 추출하기 위한 신호 결합 수단; 및 상기 신호 결합 수단에 의하여 추출된 스퓨리어스신호와 위상잡음신호를 상기 PLL 주파수 합성 수단으로 부궤환(negative feedback)시키기 위한 부궤환 수단을 포함함. 4. 발명의 중요한 용도 본 발명은 DDS 구동 PLL주파수합성 장치 등에 이용됨.
Abstract:
PURPOSE: An apparatus for canceling a transmission feedback signal and a relay system using the same are provided to have a broad frequency characteristic by canceling the transmission feedback signal and preventing the oscillation of the same frequency repeater. CONSTITUTION: An ID signal generator(301) generates an ID signal. The first power divider(302) divides the power of the output signal of the ID signal generator(301). The first coupler(303) couples the output signal of the first power divider(302) with the output signal of a repeater(400). The second coupler(305) detects the ID signal from the output signal of the repeater(400). The first correlator(306) analyzes correlation between the output signal of the second coupler(305) and the output signal of the first power divider(302), and outputs a control signal for minimizing the ID signal. An auxiliary antenna(500) receives a transmission feedback signal outputted from a transmission antenna(100). The first phase shifter(307) receives the output signal of the first correlator(306), and adjusts the phase of the transmission feedback signal inputted through the auxiliary antenna(500). The first variable attenuator(308) receives the output signal of the first correlator(306), and adjusts the level of the transmission feedback signal inputted through the first phase shifter(307). The first delay line(304) adjusts a delay time of a signal received from a reception antenna(200). The third coupler(311) couples the signal outputted through the first variable attenuator(308) with a receiving signal through the first delay line(304), and outputs a signal in which the transmission feedback signal is cancelled from the receiving signal to the repeater(400). The second delay line(309) equalizes a delay time, required for transmitting the receiving signal of the reception antenna(200) to the third coupler(311) through the first delay line(304), with a delay time required for transmitting the signal outputted through the first variable attenuator(308) to the third coupler(311).
Abstract:
PURPOSE: A high-power-output coupler and a distributor having the center frequency shift characteristics are provided to increase the impedance matching between discontinuous interfaces by controlling the length of a resonance stub according to the required frequency bandwidth and characteristics. CONSTITUTION: A main frame(100) includes a plurality of cylindrical waveguide. One side of a first coupling unit(110) is connected to plural external tracks and the other side thereof is joined with the respective waveguide, to connect respective external tracks one-to-one to the respective waveguide. One surface of a second coupling unit(120) has plural connecting surfaces connected one-to-one to the waveguide. The other surface of the second coupling unit(120) is connected to a common track to connect the respective waveguide multiple-to-one to the common track. A third ring-shaped coupling unit(130) is located between the second coupling unit(120) and the main frame(100) and assists the join between the waveguide and the connecting surfaces.
Abstract:
PURPOSE: A method for automatically measuring a digital broadcasting tuner is provided to perform frequency error connection according to an operation environment accurately and automatically. CONSTITUTION: Initialization for frequency mapping is performed to measure frequency characteristic according to frequency tuning voltage of a tracking filter of each frequency band using a pre-stage of a double frequency conversion tuner(901). The double frequency conversion tuner is measured using a spectrum analyzer(903) for frequency mapping and frequency error correction according to a signal applied to a modulator(900) when the double frequency conversion tuner is normally operated. A digital broadcasting channel signal is applied to the tuner through the modulator to carry out optimization according to a degree of variation in the frequency characteristic.
Abstract:
A radio wave sensing method for image diagnosis of breast cancer comprises a step of arranging a plurality of transceiving antennas around the breast; a step of transmitting a radio signal to at least one first antenna among the transceiving antennas; a step of receiving a scattered wave signal with respect to the radio signal from the other antennas except for the first antenna among the transceiving antennas; and a step of rotating the trasceiving antennas by a predetermined angle.