Abstract: A compensation circuit connected to an accelerometer's output extends the frequency response of the accelerometer, while reducing noise produced by the accelerometer. The compensation circuit has a gain as a function of frequency that is (i) constant up to a first frequency that is less than the accelerometer's natural resonance frequency, and (ii) reduced to approximately zero at a second frequency that is greater than the accelerometer's natural resonance frequency.

Abstract: A compensation circuit connected to an accelerometer's output extends the frequency response of the accelerometer, while reducing noise produced by the accelerometer. The compensation circuit has a gain as a function of frequency that is (i) constant up to a first frequency that is less than the accelerometer's natural resonance frequency, and (ii) reduced to approximately zero at a second frequency that is greater than the accelerometer's natural resonance frequency.

Abstract: A sensor interface circuit is provided to interface many sensors simultaneously in a simple circuit arrangement consisting of two parts. Sensors in both parts operate under identical constant voltage. The circuit provides higher front end sensitivity than the Wheatstone bridge, with temperature compensation from all sensors. The circuit also can provide output zeroing to obtain high resolution measurements. The invention can be used as a unique constant voltage anemometer with auto zeroing, and with much higher sensitivity than related devices. Further, in the constant voltage anemometer embodiment, the time constant and the overheat of the hot-wire/hot-film can be measured in true in situ mode under actual test conditions. In another embodiment, the circuit can be used to measure dynamic capacitance from capacitance sensors, without any effect of associated cable capacitance.

Abstract: A sensor circuit is provided that includes at least one pair of interconnected T-networks. Each pair has a first T-network including a first impedance serially connected to second impedance at a first junction and a first variable resistance sensor element connected to the first junction. Each pair also has a second T-network including a third impedance serially connected to a fourth impedance at a second junction and a second variable resistance sensor element connected to the second junction. The sensor circuit further includes an operational amplifier connected to the first T-network of a selected one of the at least one pair of T-networks and a constant voltage source connected to the second T-network of the selected T-network pair.

Abstract: A sensor circuit is provided that includes a first T-network including a first impedance serially connected to a second impedance at a first junction and a first variable resistance sensor element connected at a first end to the first junction and at a second end to ground. The sensor circuit also includes a second T-network including a third impedance serially connected to a fourth impedance at a third junction and a second variable resistance sensor element having first and second sensor element ends. The first sensor element end is connected to the third junction and the fourth impedance is connected to the second junction. The sensor circuit further includes a constant voltage source connected to the third impedance and to ground. The second end of the second variable resistance sensor element is connected to a fourth junction intermediate the constant voltage source and ground.

Abstract: The invention is a new and novel flow rate measuring appartus comprising constant voltage or constant power anemometers with unique electronic circuits for maintaining constant voltage or constant power to a hot film or hot wire sensor. The constant power or constant voltage mode of operation is achieved by providing an operational amplifier with a negative feedback circuit driving the hot element sensor. The hot element sensor is located along the negative feedback path of the circuit between a first and second impedance. Amplifying and filtering circuits are also provided.