Typical applications and use
- Acoustic-impedance measurements
- Exhaust-system measurements
- Near-field measurements
- Measurements at high temperatures
- Pressure-distribution measurements in smallenclosures
The Type 40SA is constructed with detachable stainless-steel probes tubes which guide the acoustic signal to a microphone inside the housing of theType 40SA. After being sensed by the microphone, the acoustic signal is passed on to an impedance matching wave guide which eliminates unwanted internal reflections. The result is a smooth frequency-response ranging from 2 Hz up to 20 kHz. The internal microphone is connected to a low-noise preamplifier with a high dynamic range; ensuring a measurement range from approximately 40 dB to 166 dB re. 20 μ Pa. The data sheet shows the preamplifier’s connections via its LEMO plug.
The Probe Microphone Type 40SA is internally compensated to equalize the internal pressure of the microphone with the static pressure at the probe’s tip . The static pressure within the Type 40SA will therefore adjust itself to the static pressure existing at the probe’s tip; which it does with a time constant of approximately 0.1 s.
The Type 40SA can be used with various probe lengths and is delivered with four standard probe lengths, i.e.: 20 mm, 40 mm, 80 mm and 160 mm. Intermediate lengths can be made by cutting these standard lengths. Also, the stainless steel tubes can be bent to a radius as low as 5 mm without downgrading the system’s acoustics. A exible probe tube is also provided for use in measurements where stiff stainless-steel tubes are not practical. This does, however, slightly downgrade the system’s acousticperformance.
The right angled design of the Type 40SA makes it particularly well suited for measurements on exhaust-gas systems and other machinery in general as well as for scanning vibrating surfaces such as loudspeaker diaphragms and cabinets.
The compact size, low weight and all-stainless-steel construction of the Type 40SA make it robust, easy to handle and easy to mount.
|Frequency range (±3 dB)||Hz||2 to 8 k|
|Dynamic range lower limit (microphone thermal noise)||dB(A)||40|
|Dynamic range upper limit||dB||166|
|Set sensitivity @ 250 Hz (±2 dB)||mV/Pa||3|
|Polarization voltage||V||200 V / Traditional|
|Power supply, single||V||120 to 28|
|Output impedance||Ω||< 50|
|Temperature range, operation||°C / °F||- 25 to 70 / -13 to 158|
|TEDS UTID (IEEE 1451.4 )||27 v. 1.0|
|Connector type||7-pin LEMO (FGG.1B.307)|
|CE/RoHS compliant/WEEE registered||Yes/Yes, Yes|
|Weight||g / oz||40 / 1.4110|
Typical frequency response with a 40 mm probe tip
|G.R.A.S. GR0265||Pistonphone adaptor for 1.25 mm|
|G.R.A.S. GR0266||Pistonphone adaptor for 1.6 mm|
|G.R.A.S. GR0267||Heatsink and tool|
|G.R.A.S. GR0275||Calibration coupler|
|G.R.A.S. GR0263||1.3 mm pin for calibration coupler|
|G.R.A.S. GR0263||1.6 mm pin for calibration coupler|
|G.R.A.S. YY0004||Pair of pliers|
|G.R.A.S. MI0016||Silicone grease|
|G.R.A.S. EK0018||Teon tubing (L: 0.5 m Dia: 1.6 mm)|
|G.R.A.S. GR0258||20 mm Probe tube|
|G.R.A.S. GR0259||40 mm Probe tube|
|G.R.A.S. GR0260||80 mm Probe tube|
|G.R.A.S. GR0261||160 mm Probe tube|
|G.R.A.S. GR0401||Flexible Probe tube|
|G.R.A.S. AA0008||Extension cable 3 m|
|G.R.A.S. 12AA||Power modules|