A wireless communication system includes a plurality of wireless sensors. A wireless sensor includes a radio frequency (RF) receiving circuit, and a sensing element, where the sensing element affects the resonant frequency of the RF receiving circuit. The wireless sensor further includes a processing module operable to determine a first value for an adjustable element of a plurality of elements for a known environmental condition, a second value for the adjustable element for an unknown environmental condition, a difference between the first and second values that corresponds to a change, and to generate a coded value representative of the change. The wireless communication system further includes one or more sensor computing devices coupled to the plurality of wireless sensors via a network. A sensor computing device includes a second processing module operable to receive the coded value and determine a sensed environmental condition based on the coded value.

A wireless communication system includes a plurality of wireless sensors. A wireless sensor includes a radio frequency (RF) receiving circuit, and a sensing element, where the sensing element affects the resonant frequency of the RF receiving circuit. The wireless sensor further includes a processing module operable to determine a first value for an adjustable element of a plurality of elements for a known environmental condition, a second value for the adjustable element for an unknown environmental condition, a difference between the first and second values that corresponds to a change, and to generate a coded value representative of the change. The wireless communication system further includes one or more sensor computing devices coupled to the plurality of wireless sensors via a network. A sensor computing device includes a second processing module operable to receive the coded value and determine a sensed environmental condition based on the coded value.

A control device includes an acquiring unit and a processing unit. The acquiring unit acquires a voltage course and a current course of a determinable number of periods of a frequency generator and transmits these to the processing unit. The processing unit determines a temporal offset t.sub.1 between a rising edge of the current course and a rising edge of the voltage course for each period of the determinable number of periods, and further determines if this temporal offset t.sub.1 is positive or negative. The processing unit determines a difference between the number of periods with positive temporal offset and the number of periods with negative temporal offset within the determinable number of periods, and generates and adapts a switching signal for a switch-on time of the voltage course if the number of periods with positive temporal offset differs from the number of periods with negative temporal offset.

A control device includes an acquiring unit and a processing unit. The acquiring unit acquires a voltage course and a current course of a determinable number of periods of a frequency generator and transmits these to the processing unit. The processing unit determines a temporal offset t.sub.1 between a rising edge of the current course and a rising edge of the voltage course for each period of the determinable number of periods, and further determines if this temporal offset t.sub.1 is positive or negative. The processing unit determines a difference between the number of periods with positive temporal offset and the number of periods with negative temporal offset within the determinable number of periods, and generates and adapts a switching signal for a switch-on time of the voltage course if the number of periods with positive temporal offset differs from the number of periods with negative temporal offset.

A frequency estimation signal generator component arranged to receive an input frequency signal and to generate therefrom a frequency estimation signal. The frequency estimation signal generator component comprises a counter component arranged to sequentially output a sequence of control signal patterns over a plurality of digital control signals under the control of an oscillating signal derived from the received input frequency signal terns. The frequency estimation signal generator further comprises a continuous waveform generator component arranged to receive the plurality of digital control signals and a weighted analogue signal for each of the received digital control signals, and to output a continuous waveform signal comprising a sum of the weighted analogue signals for which the corresponding digital control signals comprise an asserted logical state. The frequency conversion component is arranged to derive the frequency estimation signal from the continuous waveform signal output by the continuous waveform generator component.

A wireless sensor includes a radio frequency (RF) receiving circuit operable to receive an RF signal having a carrier frequency of a plurality of carrier frequencies. The RF receiving circuit further includes a variable impedance where impedance of the variable impedance is a factor in establishing a resonant frequency of the RF receiving circuit. The wireless sensor further includes a processing module that is operable to determine a first value for a first impedance of the variable impedance for a known temperature based on the resonant frequency and the carrier frequency, determine a second value a second impedance of the variable impedance for an unknown temperature based on the resonant frequency and the carrier frequency, and determine a difference between the first and second values that corresponds to a change between the known temperature and the unknown temperature.

A wireless sensor includes a radio frequency (RF) receiving circuit operable to receive an RF signal having a carrier frequency of a plurality of carrier frequencies. The RF receiving circuit further includes a variable impedance where impedance of the variable impedance is a factor in establishing a resonant frequency of the RF receiving circuit. The wireless sensor further includes a processing module that is operable to determine a first value for a first impedance of the variable impedance for a known temperature based on the resonant frequency and the carrier frequency, determine a second value a second impedance of the variable impedance for an unknown temperature based on the resonant frequency and the carrier frequency, and determine a difference between the first and second values that corresponds to a change between the known temperature and the unknown temperature.

Methods and devices for synchronizing a device clock in a wireless network (e.g. a LPWAN) are disclosed. Example methods comprise identifying a device temperature, identifying a clock drift associated with the identified device temperature and applying a correction to the device clock based on the identified drift. For the identified device temperature, the drift is identified by comparing the confidence of the drift value in a pre-calibration curve generated from fixed drift values in a pre-calibration table with the confidence of the drift value in a learning curve generated from variable drift values in a learning table and selecting the drift value from the curve having the higher drift confidence.

Methods and devices for synchronizing a device clock in a wireless network (e.g. a LPWAN) are disclosed. Example methods comprise identifying a device temperature, identifying a clock drift associated with the identified device temperature and applying a correction to the device clock based on the identified drift. For the identified device temperature, the drift is identified by comparing the confidence of the drift value in a pre-calibration curve generated from fixed drift values in a pre-calibration table with the confidence of the drift value in a learning curve generated from variable drift values in a learning table and selecting the drift value from the curve having the higher drift confidence.

An oscillation module includes an SAW filter, and a high-pass filter formed in an integrated circuit, the high-pass filter has a coil part, a capacitance part, and a first interconnection adapted to connect the coil part and the capacitance part to each other, and the capacitance part includes a capacitance array.