G.R.A.S. Type 40HT User Manual

G.R.A.S. Sound & Vibration
Single-channel Low-noise Measuring System consisting of: Type 40HT and Type 12HF - Page 5
Fig. 1.3 shows a Single-channel Low-noise Measuring system (as described in this document)
andconsistsof:
• ½-inchLow-noiseLevelMicrophoneSystemType40HT.
• PowerModuleType12HF.
Note:thepowermodulemustbeorderedseparatelyandthetripodandtripodadapterare
optionalextras.
1.1 Microphone Type 40AH
TheType40AHisaspecialhigh-sensitive½-inchmicrophone.Itisexternallypolarizedwith
aspeciallyreducedinherentnoiseoorinordertoachieveahighdynamicrangeandwide
frequencyrange.
1.2 Gain and Filter Unit Type 26HT
ThebodyoftheUnithasanoverload-warningLED,(Fig.1.1),whichisrepeatedonthefront
panel of the chosen power module (see Fig. 2.1).
Thesignalofthemicrophoneisampliedby20dBintheGainandFilterUnitType26HT.
Thetwocompensationltersgivethesystemtwoparalleloutputswhichcorrespondto:
a) linearpressure-frequencyresponse.
b) linearfree-eldfrequencyresponseatanangleof0°incidence.
Fig. 1.2 Power modules available from G.R.A.S. for Type 40HT,
Left: Single-channel Power Module Type 12HF
Right: 10-Channel Module Type 12HM
Fig. 1.3 A Single-channel Low-noise Measuring System as described
in this document, shown here with Tripod and Tripod Adapter
(both available from G.R.A.S.)
To Analyser
Type 12HFType 40HT

G.R.A.S. Type 40HT Specifications

General

Brand	G.R.A.S.
Model	Type 40HT
Category	Measuring Instruments
Language	English