Abstract
This paper presents experimental results of the frequency response of laminar proportional amplifiers (LPA). The LPA are manufactured by a wire electrical discharge machine instead of the photochemical etching process and so the accuracy of manufacturing the LPA is fairly good.
It is observed that pressure oscillation occurs at the blocked output ports with increasing the supply flow rate. The operating range of the LPA, therefore, is restricted by this oscillation. It seems that the oscillation is due to the edgetone occurring at the splitter of the output ports, but the frequency of oscillation observed is about a tenth of the wellknown experimental results of edgetone reported by G.B. Brown. It is found that the supply nozzle width should be wide and the aspect ratio be small to get a wide operating range.
The dynamic characteristics of the LPA depend strongly on the supply flow rate or the supply pressure. As the supply flow is increased, the pressure gain and the bandwidth increase with a remarkable resonant peak and the phase shift decreases.
It is also found from a low order lumped parameter analysis that the frequency response of LPA is well represented by the third order system with a transport time delay equal to twice an average particle transit time.
