摘要:
Short-range vehicular radar systems are described. In one implementation, an apparatus used in radar applications includes a programmable digital receiver having an adaptable interference filter that is configured to reject radar pulses received from another radar system. In another implementation, a short-range vehicular radar system includes receive and transmission antennae, a programmable delay generator, and programmable receiver. The programmable delay generator is configured to control transmission of pulses from the transmission antenna at randomly selected times to prevent ambiguities associated with target objects that are distances away from the transmission antenna that are greater than the speed of light times the pulse repetition rate divided by two. The programmable receiver is calibrated to sample signals received by the receive antenna relative to when the pulses are emitted from the transmission antenna.
摘要:
An apparatus for electromagnetic processing comprises a modulator for generating one or more elements representative of an input signal; a divider controlled by the one or more elements and receiving an electromagnetic wave to generate a modified signal; a comparator for comparing the modified signal to a reference signal and for generating a processed signal based upon the comparison; and a channel number calculator for selecting a channel for the processed signal, wherein the input signal incorporated the channel selection.
摘要:
A method for pre-distorting an input for a device is provided. A partial set of known data pairs is acquired during a closed-loop device calibration period. The partial set of known data pairs is searched for at least one missing data pair, and at least one data value is interpolated for the missing data pair. An augmented set of data pairs, including the known data pairs and the interpolated data value, is stored in a lookup table. During an open-loop operation period subsequent to the closed-loop device calibration period, the device input is pre-distorted based on the augmented set of data pairs stored in the lookup table.
摘要:
An antenna system for a radio frequency identification system comprising: (a) a base; (b) a first patch antenna disposed on the base and having a circular polarization and adapted to convert between electrical signals and electromagnetic fields; and (c) a second patch antenna disposed on the base and having a circular polarization and adapted to convert between electrical signals and electromagnetic fields, the second antenna being disposed at a distance from the first antenna to define a region between the first and the antenna, the second patch antenna being positioned relative to the first patch antenna such that the electromagnetic fields of the two antennas are substantially opposing in the region.
摘要:
A system and method for modulating a phase component of an electromagnetic signal includes a phase/frequency detector having first and second inputs and an output. The first phase/frequency detector input may be configured to receive a reference signal. The system may include an oscillator having an input and an output. The oscillator may be configured to generate a desired oscillator output signal at its output. A divider may be configured to receive the oscillator output signal. The divider may have a divider count input and a divider carryout output that may be connected to the second phase/frequency detector input. A loop filter may be connected in series between the phase/frequency detector output and the oscillator input. The loop filter has a transfer function including at least two frequency response rate change points, where each of the frequency rate change points corresponds to a pole or a zero in the transfer function.
摘要:
An apparatus includes a monopole extending substantially along an axis that may be vertical. However, the monopole may have a loop portion that deviates from the axis. Further, the apparatus includes multiple conductive elements, each having a substantially linear first segment that is coupled to the monopole. The first segments may be coplanar and/or perpendicular to the axis. Each of the conductive elements may further include a second segment that is substantially parallel to the axis. One or more of these segments may be connected to a ground potential. Also, the conductive elements may each include a third segment having a loop pattern.
摘要:
The invention provides a novel broadband power limiter having improved frequency characteristics and power capacity, suitable for use with GaAs low-noise amplifier circuits. The power limiter includes a shunt diode circuit and two impedance transformers. The first transformer is a step-down impedance transformer connected between the shunt diode circuit and the input to the limiter, and the second transformer is a step-up impedance transformer connected between the shunt diode circuit and the output of the limiter. The invention further provides a method for limiting the power of an input signal, comprising the steps of: transforming the input signal from the input impedance to an intermediate impedance; shunting a portion of the input signal to ground; and transforming a remaining portion of the input signal from the intermediate impedance to an output impedance. The invention further provides a novel impedance transformer suitable for use in the broadband power limiter and a method for providing such an impedance transformer.
摘要:
Apparatus, system, and method including a circuit including an element having an electrical impedance, an input node to receive a signal, and an output node to couple to a load; a sensing circuit coupled to the input node and the output node to sense a differential voltage between the input and output nodes and to sense a detected voltage at the input node; and a multiplier circuit to receive the differential voltage and to receive the detected voltage. The multiplier circuit provides an output voltage proportional to the instantaneous power delivered to the load based on the differential voltage, the detected voltage, and the impedance of the element. A system may further include a radio frequency (RF) power amplifier (PA). A method may further include controlling a gain of the RF PA to maintain the power delivered to the load at a predetermined level based on the output voltage of the multiplier circuit.
摘要:
The invention concerns a method and apparatus for estimating a height of a target object using radar signals reflected from the target object wherein a receiver detects a plurality of radar signals reflected from the target object, respectively, at a plurality of different ranges, resolves the amplitudes of the plurality of reflected signals at the respective plurality of different ranges to generate an amplitude data set, and determining if the amplitude data set correlates to a particular height.
摘要:
An embodiment is a radio system including a primary radio site and one or more fully redundant hot standby radio sites that may be activated in the event of a catastrophic failure of the primary radio site. In an embodiment, a hot standby radio site may be activated automatically to substantially avoid the radio service restoration delay that would accompany, for example, manual initiation of the failover to the hot standby radio site.