SIGNAL MONITORING METHOD FOR SENSING APPLICATIONS

摘要

A system and method to accurately estimate the strength and changes of the monitoring signal for sensing applications, this invention involves the monitoring of signal strength and changes through the use of a pseudorandom binary sequence bit stream to modulate the transmitter of a data link, when beating the transmitter signal with absorption structure signal from the sensor at the receiver, the changes in the received signal strength are proportional to the sensing signal being monitored. The received signal bit pattern is monitored by an error detector scheme to report a Bit Error Rate level based on the changes in the sensing signal level as compared to the bit stream from the transmitter. This results in a very accurate robust monitoring technique with high consistency and repeatability.

主权项

1. A method for detecting trace gas concentrations with high resolution, wherein the method comprises of:
configuring a tunable laser to emit wavelengths at a tuned frequency; configuring at least two units, wherein one of the at least two units provides output from the tunable laser to an absorption cell for attenuating the light wave from the tunable laser at certain wavelength and transmits the signal to a modulator and the other unit of said at least two units is a sensing signal received from a remote atmospheric light collimator that collects data and injects it through an optical fiber as an input or an output of the modulator; modulating the signal with pseudorandom binary sequence generated by a pulse pattern generator; transmitting signal from the modulator to a receiver; beating the transmitted signal with an absorption structure signal received from the sensor configured at the receiver; configuring a decision threshold circuit to receive the output from the receiver; configuring a signal generator for emitting an electrical signal for optimization and providing the RF connection to an error detector; configuring the error detector to receive an output signal bit sequence and comparing the input and the output bit sequence for generating a BER value that corresponds to the signal strength received at the input of the receiver; and comparing the baseline BER with an error detector BER resulting in difference in a BER performance, which correspond to the absorption strength of the gas in the cell.