Systems and methods for interrogating sensing systems utilising bursts of samples. Bursts of samples correspond to optical pulses returning from optical sensors, where pulses are spaced at a period significantly longer than the pulse width, giving irregular sample spacing. The interrogation system and method processes the irregular busts of samples to recover phase information from received signals.

Systems and methods for interrogating sensing systems utilising bursts of samples. Bursts of samples correspond to optical pulses returning from optical sensors, where pulses are spaced at a period significantly longer than the pulse width, giving irregular sample spacing. The interrogation system and method processes the irregular busts of samples to recover phase information from received signals.

An example apparatus includes: an input adapted to receive a signal modulated with data, counter circuitry coupled to the input and operable to determine a first count value in response to a first period between a first rising edge of the signal and a second rising edge of the signal, the first rising edge indicative of a start bit of the data, and determine a second count value based on a second period between a first falling edge of the signal and a second falling edge of the signal, data capture clock circuitry coupled to the counter circuitry and operable to generate a data capture clock based on the first count value in response to the second count value satisfying a threshold, and demodulator circuitry coupled to the counter circuitry and the data capture clock circuitry, the demodulator circuitry operable to generate a demodulated signal based on the data capture clock.

A frequency modulation demodulation device and a control method thereof are provided. The frequency modulation demodulation device includes an input terminal, a phase converter, a phase-locked loop circuit, and a frequency offset/shift detector. The phase converter receives an input signal to obtain a phase signal. The phase-locked loop circuit generates a phase adjustment signal according to the phase signal and adjusts the phase signal according to the phase adjustment signal to perform demodulation of the input signal. The phase-locked loop circuit performs signal alignment and signal compensation on the phase signal to generate a filtered phase signal. The phase adjustment signal provides a feedback of and adjusts the phase signal. The frequency offset/shift detector generates a frequency offset/shift determining signal according to the phase adjustment signal. The frequency offset/shift determining signal is related to a phase frequency offset/shift of the input signal.

The present disclosure relates to a method of analyzing a pulse modulated signal, wherein the method comprises: receiving a pulse modulated signal; determining a dynamic threshold level based on a period of the pulse modulated signal and the pulse modulated signal; and demodulating the pulse modulated signal by the dynamic threshold level. Moreover, a signal analysis instrument for analyzing a pulse modulated signal is described.

The present disclosure relates to a method of analyzing a pulse modulated signal, wherein the method comprises: receiving a pulse modulated signal; determining a dynamic threshold level based on a period of the pulse modulated signal and the pulse modulated signal; and demodulating the pulse modulated signal by the dynamic threshold level. Moreover, a signal analysis instrument for analyzing a pulse modulated signal is described.

An example apparatus includes: an input adapted to receive a signal modulated with data, counter circuitry coupled to the input and operable to determine a first count value in response to a first period between a first rising edge of the signal and a second rising edge of the signal, the first rising edge indicative of a start bit of the data, and determine a second count value based on a second period between a first falling edge of the signal and a second falling edge of the signal, data capture clock circuitry coupled to the counter circuitry and operable to generate a data capture clock based on the first count value in response to the second count value satisfying a threshold, and demodulator circuitry coupled to the counter circuitry and the data capture clock circuitry, the demodulator circuitry operable to generate a demodulated signal based on the data capture clock.

A frequency modulation demodulation device and a control method thereof are provided. The frequency modulation demodulation device includes an input terminal, a phase converter, a phase-locked loop circuit, and a frequency offset/shift detector. The input terminal receives an input signal. The phase converter is coupled to the input terminal and receives the input signal to obtain a phase signal. The phase-locked loop circuit is coupled to the phase converter to generate a phase adjustment signal according to the phase signal, and the phase-locked loop circuit adjusts the phase signal according to the phase adjustment signal to perform demodulation of the input signal. The frequency offset/shift detector is coupled to the phase-locked loop circuit and generates a frequency offset/shift determining signal according to the phase adjustment signal obtained from the phase-locked loop circuit. The frequency offset/shift determining signal is related to a phase frequency offset/shift of the input signal.

A frequency-voltage conversion circuit includes a constant current source, a first switch connected to an output of the constant current source, a first capacitor connected between the first switch and ground, a second switch connected between a first node that is between the first switch and the first capacitor, and an output node, a third switch connected between the first node and the ground, a fourth switch connected to the output of the constant current source, a second capacitor connected between the fourth switch and the ground, a fifth switch connected between a second node that is between the fourth switch and the second capacitor, and the output node, and a sixth switch connected between the second node and the ground.

A frequency-voltage conversion circuit includes a constant current source, a first switch connected to an output of the constant current source, a first capacitor connected between the first switch and ground, a second switch connected between a first node that is between the first switch and the first capacitor, and an output node, a third switch connected between the first node and the ground, a fourth switch connected to the output of the constant current source, a second capacitor connected between the fourth switch and the ground, a fifth switch connected between a second node that is between the fourth switch and the second capacitor, and the output node, and a sixth switch connected between the second node and the ground.