摘要:
Methods for detecting and correcting data errors in an RF data link include identifying valid data frames and corrupted data frames by measuring a data corruption level for each transmitted data frame, comparing the measured data corruption level for each corrupted data frame to a data corruption threshold, reconstructing the corrupted data frames having a data corruption level below the data corruption threshold, reconstructing the data block using data from valid and reconstructed data frames, and/or verifying the data in the reconstructed data block.
摘要:
A pressure sensing device (10), such as a tire pressure monitoring unit comprises a pressure sensor (11) for measuring pressure of a fluid, such as air or an inert gas, in an environment external to the device, such as within the cavity of a tire. A hollow resonator (24), or standing wave tube, is coupled to the pressure sensor. The resonator has a free (28) end exposed to the external environment to the extent that pressure variations in the fluid are propagated through the hollow resonator to the pressure sensor via the free end. The hollow resonator has a resonant frequency substantially matching a target frequency such that resonance is established in the tube at the resonant frequency in response to the presence of an audio signal in the fluid having a frequency that substantially matches the target frequency.
摘要:
A tire pressure detector employs a reduced power consumption mechanism comprising a PLL circuit including a VCO, that is operated in response to the logic states of an input data stream and a power amplifier configured to be externally located to an integrated circuit. The input data stream includes tire pressure information and is configured to be encoded to have multiple logic states. A micro¬ controller is employed to control the VCO, turning the VCO, and/or the amplifier, on and off for a certain period, according to the pattern of each data bit of the input data stream thus providing reduced current consumption. This tire pressure detector thus embodies an optimized circuit arrangement in terms of power efficiency.
摘要:
An apparatus and method for performing temperature compensation in a tyre pressure monitoring system. Temperature compensation is performed with respect to a reference temperature value that is adjusted in response to determining that ambient temperature has changed. Active adaptation of the reference temperature ensures that temperature compensation is matched to the ambient conditions of the drive so that system sensitivity is maintained closer to design intended levels in all seasons.
摘要:
Methods for detecting and correcting data errors in an RF data link include identifying valid data frames and corrupted data frames by measuring a data corruption level for each transmitted data frame, comparing the measured data corruption level for each corrupted data frame to a data corruption threshold, reconstructing the corrupted data frames having a data corruption level below the data corruption threshold, reconstructing the data block using data from valid and reconstructed data frames, and/or verifying the data in the reconstructed data block.
摘要:
An apparatus for detecting motion of a wheel comprising tyre. The apparatus comprises a pressure sensor for measuring the tyre pressure and generating a signal corresponding to the measured tyre pressure, and means for detecting a component of said signal that corresponds to, or is generated by, vibrations of the tyre. Upon detection of the signal component, the apparatus determines that the wheel is in motion. The detecting means may arranged to detect an audio signal component or signal components having a frequency in the range 200 Hz to 300 Hz.
摘要:
A tire monitor for mounting on a wheel rim, the tire monitor comprising a housing having a first part (644A) configured to receive a component substrate (645) and a second part (644B) configured to receive one or more other components of the tire monitor, for example a battery. The first and second parts of the housing are non-coplanar and non-parallel with one another. When the tire monitor is mounted on the wheel rim, the substrate is non-coplanar and non-parallel with a plane (T) that is tangential to the wheel rim at the location where the tire monitor is mounted on the rim and preferably the substrate plane is substantially radial with respect to the wheel rim.
摘要:
An automotive urea solution monitoring device is deployed in conjunction with the urea tank of a selective catalytic reduction vehicle. An RF signal of a constant frequency may be generated across a resonant circuit, which may be comprised of an inductor and a PCB trace capacitor, or the like. Electromagnetic radiation is propagated into the automotive urea solution in the urea tank. The conductivity and dielectric properties of the liquid change the impedance of the discrete/trace capacitor and or the discrete/trace inductor. These changes are proportional to ammonia content, temperature, and/or level of the automotive urea solution in the urea tank and are preferably detected by a microcontroller, or the like, and then transmitted to a selective catalytic reduction vehicle engine management system, or the like.
摘要:
An apparatus and method for adjusting pressure thresholds in a tyre pressure monitoring system. The apparatus maintains pressure threshold values, and adjusts them relative to a measured tyre pressure value when it is determined that the measured tyre pressure value exceeds a nominal value. The pressure threshold values are decreased in response to determining that the measured tyre pressure has decreased by more than a threshold amount. This allows pressure thresholds to be adapted in response to deliberate changes in tyre pressure and so to maintain a desired sensitivity. In particular, the preferred methods and apparatus enable differentiation between a deliberate deflation and a natural leakage and cause thresholds to be adapted in response to the former and not the latter.