摘要:
A vehicular antenna is mounted on a circuit board in a monitor. The circuit board has a conductor substrate that is used as a ground for the antenna, and it has a frame shape that has a rectangular inner edge. The circuit board has an electrical contact for connecting the antenna. The electrical contact is placed at λ/4 away from an axisymmetrical line (center line) with respect to the inner edge. As a result, a gain of the vehicular antenna is not reduced in a front direction even when the vehicular antenna uses the frame shape conductor as the ground.
摘要:
In a wireless communication system, a portable device transmits a first signal spread based on a reference period indicated by a synchronization signal transmitted from an in-vehicle device and transmits a second signal spread based on an operation by a user. The in-vehicle device sets a search period based on a variation range in a delay time from when the synchronization signal is transmitted to when the spread first signal is transmitted and sets a residual period that starts at an ending point of the search period and ends at an ending point of the reference period when a starting point of the reference period is set at a starting point of the search period. When the in-vehicle device fails in a synchronous acquisition for the search period, the in-vehicle device performs a synchronous acquisition process for the residual period.
摘要:
A batteryless tire inflation pressure detecting apparatus includes, on the body of a vehicle, antennas and a transmitter transmitting radio waves through the antennas. The apparatus also includes, on each wheel of the vehicle, a pressure sensor sensing the pressure of a tire, a transceiver, and a charging unit powering the pressure sensor and the transceiver. The charging unit is charged with electric power induced by a corresponding one of the radio waves received by the transceiver. The apparatus further includes, on the body of the vehicle, a receiver receiving pressure signals transmitted by the transceivers, a pressure determiner determining the pressures of the tires based on the pressure signals, and a controller. To minimize influence of the radio waves on neighboring devices, the controller controls the transmitter so that least two of the radio waves are transmitted at different times, or at the same with a phase difference therebetween.
摘要:
An antenna apparatus includes an antenna and support member. The antenna has a double spiral structure to include (i) an outer element, which has a spiral section prolonged spirally in an axial direction, and (ii) an inner element, which has a spiral section prolonged spirally in the axial direction and is surrounded with an interval space by the outer element. The support member is made of dielectrics and holds the two elements in a predetermined positional relationship by contacting the spiral sections of the two elements. The support member contacts the spiral sections wholly along the prolonged direction. One of the two elements is connected with a high frequency wave source at one end portion along the axial direction while the other is connected with the high frequency wave source at the other end portion along the axial direction. The antenna functions as a terminal short circuit type.
摘要:
A receiving device for spread spectrum communication includes a phase determining unit and a data demodulating unit. The receiving device receives a signal spread and modulated with first spreading code. The phase determining unit calculates a cross correlation between the received signal and a second spreading code and determines a phase P(0) of the received signal based on the cross correlation. The data demodulating unit synchronizes the phase P (0) and the first spreading code and despreads and demodulates the received signal with the first spreading code. The number of components in each of the first spreading code and the second spreading code is an integer greater than or equal to 2.
摘要:
A first trigger unit and a second trigger unit output trigger signals to transceivers disposed for the four wheels of a vehicle. The first and second trigger units are attached to wall surfaces of tire housings corresponding to the left front and left rear wheels respectively. Each of the first and second trigger units is arranged in a position of the wall surface having an angle from 5 to 25 degrees with respect to the side of the corresponding wheel. Transceivers attached to a right front and right rear wheels are thus located farther from the trigger units than the left front and left rear wheels, respectively. Such arrangement allows the transceivers attached to the right front and right rear wheels to receive the outputted trigger signals with sufficient accuracy due to high field strength.
摘要:
An opening area between twisted portions of a pair of twisted wires is arranged to be opposite to an opening area of an aperture antenna of each of communication apparatuses. Thus, the use of the pair of twisted wires permits division of electric power among the communication apparatuses and also communication of signals. In particular, among the opening areas between the twisted portions of the pair of twisted wires, only an opening area, which is in between the twisted portion and the twisted portion and is opposite to the aperture antenna, is formed to be larger than a different opening area. This provides a vehicular power line communication system and a transmitter in the system; the system strengthens electromagnetic induction connection between the transmitter and the receiver to permit power line communication.
摘要:
An onboard apparatus control system is disclosed. The onboard apparatus control system includes a portable apparatus and an in-vehicle apparatus which controls an onboard apparatus according to position of the portable apparatus. From multiple transmitting antennae, the in-vehicle apparatus transmits pulse pattern signals with different transmission frequencies at an overlapping timing, so that the pulse pattern signals are radio waves whose intensities are changed stepwise according to different patterns. The portable apparatus receives the radio waves transmitted from the multiple transmitting antennae. The position of the portable apparatus with respect to the vehicle is determined based on a combined pattern of the received pulse pattern signals, which a receiving unit is to receive at location with respect to the vehicle.
摘要:
A matching circuit, connected to a receiving antenna and to the input of a receiving circuit, incorporates a variable capacitor that is adjustable for tuning the resonance frequency of the antenna to a desired reception frequency. In an automatic tuning mode of operation, an oscillator signal of different frequency from the reception frequency is applied to induce resonance of the antenna and matching circuit, and the variable capacitor is adjusted until an output signal level from the receiving circuit attains a predetermined value which has been stored beforehand in a memory and which corresponds to a condition whereby the antenna resonance frequency corresponds to the reception frequency and impedance matching exists between the antenna and receiving circuit.
摘要:
In a filter circuit, first and second coils are connected to first and second communication lines, respectively. At a secondary side of the first and second coils, first and second capacitors are connected in series between the first and second communication lines. At a primary side of the first and second coils, third and fourth capacitors are connected in series between the first and second communication lines. A connection node between the first and second capacitors is grounded. A connection node between the third and fourth capacitors is grounded. The first and second coils are adjacently arranged in order to have a reversed polarity to each other. The filter circuit having the above structure works as a n-type filter capable of eliminate both common mode noise and normal mode noise. The filter circuit can eliminate noise caused by the first and second coils.