1/4 "フリーフィールドマイクロスコープ、外部偏光
1/4 "フリーフィールドマイクロスコープ、外部偏光
4Hz～70kHzの周波数応答を持つ、高レベルおよび高周波測定用に設計された圧力屋外TEDSマイクロホン。
TYPE 4939
ステンレス製の振動板と保護グリッドを採用した4939型マイクロホンは、過酷な環境にも耐えることができ、最高150℃までの高温測定にも対応します。
外部偏極型マイクは、測定感度を大きく変化させることなく、より高い温度で使用することができます。
| Document | タイプ | 言語 |
|---|---|---|
| ¼-inch Free-field Microphone Type 4939 Datasheet (bp1851) | データシート | English |
| プロパティ | 値 |
|---|---|
| Standard | IEC 61094 |
| Sound field | Free field |
| Polarization voltage | 200V |
| Sensitivity | 4 mV/Pa |
| Lower limiting frequency | 4 Hz |
| Higher limiting frequency | 100 kHz |
| Inherent noise | 28 dB(A) |
| Upper limiting of dynamic range | 164 dB |
| Diameter | 1/4 inch |
| Venting | Side |
| Minimum Temperature | -40 °C |
| Maximum Temperature | 150 °C |
| Minimum Temperature | -40 °F |
| Maximum Temperature | 302 °F |
A laser-welded, stainless-steel diaphragm ensures superior long-term stability and mechanical robustness. Type 4939 will withstand the 1 m drop test required by IEC 60068-2-32.
The microphone is assembled in a clean room, ensuring that the microphones maintain their inherent noise floor and high stability, even when used in environments with a combination of high humidity and high temperature.
Type 4939 is available in a TEDS Microphone set with different variants of classical preamplifiers. The TEDS microphone is considered one unit and has been sealed in a clean environment.
The TEDS is programmed with the loaded sensitivity of the actual cartridge and the data is therefore readily available in the transducer. The default TEDS template is according to IEEE P1451.4 but TEDS to IEEE 1451.4 is available on request.
The sensitivity can be calibrated at 250 Hz by using Pistonphone Type 4228 with ¼-inch Adaptor DP 0775. The actuator response can be measured using Actuator UA 0033 with Adaptor DB 0264.
The free-field response can be obtained by adding the type-specific, free-field correction to the actuator response.
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