An automated coupler calibration system for laboratory standard condenser microphones Free

An automated coupler calibration system for laboratory standard condenser microphones is manufactured for trial use. Active couplers whose cylindrical wall vibrates as a sound source are designed. These couplers are used so as to get pressure response levels of microphones in a short time and to reduce manual transaction. A microcomputer controls the system, processes measured values, examines them, and stores final results in a diskette. In addition, many digital techniques are adopted for noise reduction and for the convenience of calibration. Accuracies were tested for 1‐in. condenser microphones, such as MR103, using a coupler which has the same dimensions as the 20‐cm³ a coupler. Pressure response levels calibrated by the system agree well with those calibrated by the ordinary precise coupler calibration system within 0.2 dB at the frequencies 100–10 000 Hz.