Abstract
This paper presents a new design of a pneumatic coupling condenser and experimental data of its performance. This device consists of three parts: an input chamber, a modulating chamber and an output signal transmitter. The modulating chamber is a thin cylindrical chamber which is confined with a diaphragm at each side and has a vent equipped with a restrictor. The output signal transmitter is merely a usual pneumatic micrometer (back-pressure type) which transduces a displacement of the center portion of the output diaphragm into an output signal.
Features of this device are shown as follows.
1) An input impeadance to a signal flow is infinite.
2) Output signals contain no direct flow components of input signals.
3) In the frequency response, the gain is independent of the vent resistance in the frequency range well above the break-point frequency and the break-point frequency is inversely proportional to the vent resistance.
4) This device acts as a low-cut and highpass filter.
5) This device has a differentiating function.
The frequency responses of the models equipped with laminar vent restrictors and orifice are measured. In the case of the laminar vent restrictor, the experimental values are compared with the calculated ones. The results show a good agreement.
Furthermore, the effects of design parameters on the characteristics of a pneumatic coupling condenser are discussed.
