| 20110169649 | GAS SENSING METHOD AND INSTRUMENT THEREFOR - A method and instrument capable of producing an audible tick that increases with detected gas concentrations, is suitable for indicating relatively low levels of gas concentrations, and enables the adjustment of the tick rate to provide an accurate audible indication of gas levels at higher concentrations. The method and instrument entail sensing the presence of the gas and generating an analog sensor output based on a concentration of the gas in the environment, and then processing the analog sensor output through an audio circuitry to generate therefrom an audible tick having a frequency in proportion to the analog sensor output. The processing step includes the use of an analog control loop signal to selectively increase and decrease the frequency of the audible tick. | 07-14-2011 |
