Abstract:
Two receive antennas integrated with power detectors are used to align the thrust vector of a vehicle to the boresite of an automotive radar antenna mounted upon the vehicle. In the system, a signal is transmitted from the radar antenna to the Radar Test System (RTS) positioned as an amplitude only interferometer for testing the radar. Signals received by the RTS antennas are provided to amplitude detectors for generation of amplitude plots of a difference signal, or alternative signal, for display. The boresite angle of the radar antenna is then adjusted until the amplitude of the difference signal, or alternative signal, reaches a minimum to align the radar antenna boresite with the vehicle thrust vector. Additional pairs of receive antennas and detectors may be used to provide boresite alignment both in azimuth and elevation.
Abstract:
A test system is provided operating in the 76-77 GHz range for testing components of a collision avoidance radar system. The system uses a Scorpion vector network analyzer (VNA) having an internal stimulus source synthesizer operating over a narrow 3-6 GHz range. The source signal from the Scorpion VNA is up-converted in a test module to a 75-78 GHz signal, without using a non-linear multiplier between the Scorpion VNA source and a device under test (DUT). A 72 GHz. local oscillator (LO) signal is provided for up-conversion as well as down-conversion using a dielectric resonator oscillator (DRO) phase-locked to a crystal oscillator of the Scorpion VNA. The DRO is included internal,to the test module. Fundamental up-conversion and down-conversion is provided in the test system so that significant conversion losses do not occur, as when higher order harmonics are used.
Abstract:
A calibration technique for a vector network analyzer (VNA) enabling calibration standards to be included internal to the VNA. To calibrate the VNA utilizing the internal calibration standards, error terms a, b and c of two two-port error boxes E are defined between the measurement ports and the reflectometer of the VNA wherein a=-det(E), b=e00 and c=e10. Error terms a, b and c are determined by measuring external calibration standards with known reflection coefficients connected directly to the measurement ports. Reflection coefficients for internal calibration standards are then determined using the error terms a, b and c to enable future automatic calibrations. To measure S-parameters of an arbitrary device under test (DUT), one embodiment of the present invention uses the Ferrero technique to measure a reciprocal thru with estimated S.sub.21 characteristics connected between ports A and B to determine an additional error term .alpha. for the error boxes E, where .alpha.=e01.sub.A /e.sub.01B. In another embodiment a thru is measured which is not required to be reciprocal or to have known S.sub.21 characteristics, both alone and in series with the DUT.
Abstract:
YIG oscillator apparatus comprises both an FET-based YIG oscillator circuit and a bipolar transistor-based YIG oscillator circuit inside a single magnetic structure. Both YIG spheres are disposed in the single air gap of the magnetic structure, which is defined by a pole piece which is tapered to an elongated pole surface which is only slightly larger than necessary to cover both YIG spheres. A band reject filter is included inside the housing for rejecting second harmonics of desired oscillation frequencies only.
Abstract:
Apparatus for measuring the noise parameters of a device under test (DUT), with full compensation for impedance mismatches between the DUT and the test apparatus. The apparatus includes an S-parameter measuring device, such as vector network analyzer (VNA), combined with a noise module. The noise module includes, among other things, a pair of test ports for the DUT, a noise source which can be turned on or off by an external controller, a receiver, and a switch for coupling the output of the DUT to selectably either the receiver or port 2 of the VNA.
Abstract:
YIG oscillator apparatus comprises both an FET-based YIG oscillator circuit and a bipolar transistor-based YIG oscillator circuit inside a single magnetic structure. Both YIG spheres are disposed in the single air gap of the magnetic structure, which is defined by a pole piece which is tapered to an elongated pole surface which is only slightly larger than necessary to cover both YIG spheres.
Abstract:
A method and apparatus comprising a sampler frequency converter having a first and a second diode. A local oscillator having a frequency F.sub.LO, a step recovery diode and a balun transformer are used for providing positive and negative sampling pulses to the diodes for sampling an input signal applied to the diodes having a frequency F.sub.IN. An output signal is provided by the diodes having a frequency F.sub.OUT which is defined by the relationship F.sub.OUT .vertline.F.sub.IN .+-.N.times.F.sub.LO .vertline. where N is an integer harmonic number 1, 2, 3 . . . and the output signal has an amplitude which varies as a function of (sin x)/x where x=F.sub.IN. A bandpass filter is provided which is responsive to the output signal for filtering a predetermined band of frequencies therefrom and a bias circuit is provided for forward biasing the diodes so that the frequency F.sub.IN of said input signal at which nulls occur in said (sin x)/x relationship occur at a lower frequency after said biasing than before said biasing.
Abstract:
A vector network analyzer comprising a circuit for measuring the real and imaginary components of the central spectral line in an RF pulse from a device-under-test is provided. The circuit comprises a modulator in response to a profiling pulse for modulating the amplitude of the RF pulse, mixers for down-converting the frequency of the amplitude modulated RF pulse, a narrow band filter for filtering the RF pulse having a bandwidth of 500 Hz and a synchronous detector responsive to the output of the crystal filter for providing a pair of dc outputs, which correspond to the real and imaginary components of the output of the device under test as the profiling pulse is shifted in time relative to the RF pulse.
Abstract:
An automotive radar test system includes circuitry for multiple down and up conversions of a signal from the automotive radar. Conditioning circuitry delays an intermediate frequency signal (IF2) obtained after a second down conversion to simulate the delay of a return signal from an object located a particular distance from the automotive radar, and to attenuate the IF2 signal to simulate variable target sizes, and to generate a Doppler shift in the IF2 signal to simulate target speed. The conditioned signal is up-converted and transmitted back to the automotive radar system to determine if the automotive radar provides accurate readings for distance, size and speed. The radar test system further couples the second IF signal to a spectrum analyzer to determine if the automotive radar is operating in the desired bandwidth and to a power meter to determine if the automotive radar is transmitting at a desired power level.
Abstract:
An automobile collision avoidance radar antenna alignment system includes a first interferometer (506) with antennas (501) and (503) for alignment along an azimuth (x) axis of the collision avoidance radar antenna, and a second interferometer (508) with antennas (502) and (504) for alignment along an elevation (y) axis of the collision avoidance radar. Difference azimuth (.DELTA..sub.AZ) and difference elevation (.DELTA..sub.EL) outputs of the interferometers (506) and (508) are added (.DELTA..sub.T =.DELTA..sub.AZ +.DELTA..sub.EL) with the amplitude of (.DELTA..sub.T) provided at a power detector (526). Sum azimuth (.SIGMA..sub.AZ) and sum elevation (.SIGMA..sub.AZ) are added (.SIGMA..sub.T =.SIGMA..sub.AZ +.SIGMA..sub.EL) with the amplitude of (.SIGMA..sub.T) provided to a power detector (547). To align a collision avoidance radar antenna, the antennas of the antenna alignment system are positioned with a centerline parallel to the thrust vector of the automobile using a laser beam fixture 204. Azimuth and elevation translation errors (.DELTA.x) and (.DELTA.y) between antennas of the antenna alignment system and the antenna of the collision avoidance radar are removed by moving the antenna alignment system until the total difference signal (.DELTA..sub.T) is a minimum. The angle (.alpha.) between the boresite of the collision avoidance radar antenna and the thrust vector of the automobile is set to zero by adjusting the collision avoidance radar antenna until the total sum signal (.SIGMA..sub.T) is a maximum.
Abstract translation:汽车碰撞避免雷达天线对准系统包括:具有天线(501)和(503)的第一干涉仪(506),用于沿着防撞雷达天线的方位角(x)轴线对准;以及第二干涉仪(508),其具有天线 502)和(504),用于沿着防撞雷达的高度(y)轴进行对准。 在功率检测器(526)处提供具有(DELTA T)幅度的干涉仪(506)和(508)的差分方位角(DELTA AZ)和差分高程(DELTA EL)输出(DELTA T = DELTA AZ + DELTA EL) )。 加上方位角(SIGMA AZ)和总高程(SIGMA AZ)(SIGMA T = SIGMA AZ + SIGMA EL),其幅度为(SIGMA T)提供给功率检测器(547)。 为了对准碰撞避免雷达天线,使用激光束固定装置204将天线对准系统的天线定位成与汽车的推力矢量平行的中心线。方位角和仰角平移误差(DELTA x)和(DELTA y) 通过移动天线对准系统直到总差分信号(DELTA T)为最小值来去除天线对准系统的天线和避碰雷达的天线。 避碰雷达天线的射孔与汽车的推力矢量之间的角度(α)通过调整避雷雷达天线直到总和信号(SIGMA T)最大为止设置为零。