Product Data Outdoor Microphone System for permanent noise monitoring applications Nor1210A and Nor1210C The Outdoor Microphone System Type Nor1210A (vertical incidence) and Nor1210C (horisontal incidence) are for outdoor use whenever troublefree acoustic measurements and, in particular, community and traffic noise monitoring are required. It complies with IEC 60651 Type 1, IRC 61672-1 Class1 and ANSI S1.4 1983 Type 1 requirements and can be used with any suitable electronic sound or vibration measurement system. It is PTB approved as part of an IEC 60651 Type 1 system. A 1⁄2-inch precision condenser microphone and thick-lm preampli er ensure maximum stability and performance. Both microphone and casing are made of stainless steel. Precise in-situ calibration checks at 1000 Hz are enabled any time via a built-in electrostatic actuator and test oscillator. The Nor1210 is fitted with antibird spikes, a windscreen, and a rain cap which is an integral part of its acoustic omnidirectional characteristics. The rain cap, which contains the electrostatic actuator, remains in position while calibrating the microphone with a pistonphone. The large dynamic range of the microphone system is obtained via a twin circuit board with a DC converter for supplying 200 V for microphone polarization as well as a 120 V supply for the preamplier. The sensitivity of the amplifier can be adjusted by 12 dB and the gain changed by ± 20 dB (via a pair of circuit-board jumpers) to give optimum signal-to-noise ratio on long cables. The gain is normally set to 0 dB when skipped from the factory. An A-weighting filter for increased dynamic capability is included in the Nor1210. A circuit-board jumper is used to select either the Aweighting or linear frequency re(Continued on page 2)

(Continued from page 1) sponse. A-weighting or linear response can be specified when ordering, otherwise Lin-weighting will be active on delivery. The built-in calibration oscillator can be switched on or off by shortcircuiting a pin to ground in the output socket of the Nor1210. The electrostatic actuator is factory set to a calibration level of 90 dB re. 20 μ Pa at 1000 Hz. A calibration level of 94 dB can be specified when ordering. The electrostatic actuator and microphone assembly is electrically isolated from the casing of the Nor1210; thus eliminating EMC and ground loops. A silica-gel...