A pulse-width-to-voltage (PWV) converter, comprises: a switch, a capacitor, a current source, and a current sink. The switch is operable by a signal. The current source, the current sink, and the switch are serially connected across a high voltage potential and a low voltage potential. An output node is coupled to a serial connection between the current source and the current sink. An end of the capacitor is coupled to the output node for converting a current into a control voltage indicative of a duty cycle of the signal.

A pulse-width-to-voltage (PWV) converter, comprises: a switch, a capacitor, a current source, and a current sink. The switch is operable by a signal. The current source, the current sink, and the switch are serially connected across a high voltage potential and a low voltage potential. An output node is coupled to a serial connection between the current source and the current sink. An end of the capacitor is coupled to the output node for converting a current into a control voltage indicative of a duty cycle of the signal.

A demodulator for pulse-width modulated clock signals is disclosed. In one aspect, the demodulator includes an edge detector configured to detect transitions in a reference clock and output a signal indicative of timing of the detected transitions. The demodulator may also include a modulation detection circuit configured to identify modulation events of at least one pulse-width modulated pulse in the reference clock based on the signal output from the edge detector and output a signal indicative of the at least one pulse-width modulated pulse modulation event being identified. The demodulator may further include a retiming circuit configured to generate an output clock synchronized with the at least one pulse-width modulated pulse modulation event based on the signal output from the modulation detection circuit.

A demodulator for pulse-width modulated clock signals is disclosed. In one aspect, the demodulator includes an edge detector configured to detect transitions in a reference clock and output a signal indicative of timing of the detected transitions. The demodulator may also include a modulation detection circuit configured to identify modulation events of at least one pulse-width modulated pulse in the reference clock based on the signal output from the edge detector and output a signal indicative of the at least one pulse-width modulated pulse modulation event being identified. The demodulator may further include a retiming circuit configured to generate an output clock synchronized with the at least one pulse-width modulated pulse modulation event based on the signal output from the modulation detection circuit.

Systems, methods, and circuits for determining a duty cycle of a periodic input signal are provided. A delay element is configured to delay the periodic input signal based on a digital control word. A digital circuit is configured to generate a first digital control word used to delay the periodic input signal a first amount of time corresponding to a period of the periodic input signal, generate a second digital control word used to delay the periodic input signal a second amount of time corresponding to a portion of the periodic input signal having a logic-level high value, and generate a third digital control word used to delay the periodic input signal a third amount of time corresponding to a portion of the periodic input signal having a logic-level low value. A controller is configured to determine the duty cycle based on the first, second, and third digital control words.

A gas sensor system and a method of operating the gas sensor system can include a group of sensors and a microcontroller that can receive sensor measurements from the group of sensors. Feedback from the group of sensors can generate a sensor offset and a pulse width modulation (PWM) demodulator can be varied to reduce the sensor offset to null and provide sensor-to-sensor variations, which are independent of error in the sensor measurements.

A gas sensor system and a method of operating the gas sensor system can include a group of sensors and a microcontroller that can receive sensor measurements from the group of sensors. Feedback from the group of sensors can generate a sensor offset and a pulse width modulation (PWM) demodulator can be varied to reduce the sensor offset to null and provide sensor-to-sensor variations, which are independent of error in the sensor measurements.

A circuit for decoding a pulse width modulated (PWM) signal generates an output signal switching between a first and second logic values as a function of a duty-cycle of the PWM signal. Current generating circuitry receives the PWM signal and injects a current to and sinks a current from an intermediate node as a function of the values of the PWM signal. A capacitor coupled to the intermediate node is alternatively charged and discharged by the injected and sunk currents, respectively, to generate a voltage. A comparator circuit coupled to the intermediate node compares the generated voltage to a comparison voltage and drives the logic values of the output signal as a function of the comparison.

A circuit for decoding a pulse width modulated (PWM) signal generates an output signal switching between a first and second logic values as a function of a duty-cycle of the PWM signal. Current generating circuitry receives the PWM signal and injects a current to and sinks a current from an intermediate node as a function of the values of the PWM signal. A capacitor coupled to the intermediate node is alternatively charged and discharged by the injected and sunk currents, respectively, to generate a voltage. A comparator circuit coupled to the intermediate node compares the generated voltage to a comparison voltage and drives the logic values of the output signal as a function of the comparison.

A multidimensional symbol encoder is coupled to a transmitter. Multidimensional symbols are encoded by concatenating two or more partial symbols, wherein individual intervals of up and down sections of the two or more partial symbols are independently controlled as to duration. A multidimensional symbol decoder is coupled to a receiver. Multidimensional symbols are decoded by measuring duration of individual intervals i) that are independently controlled as to duration and ii) that are up and down sections of two or more concatenated partial symbols.