GRAS 44AB Mouth Simulator according to ITU-T Rec. P51
ITU-T rec.: P.51
IEEE standards: 269, 661
GRAS 44AB Mouth Simulator is a sound source that simulates the sound field around the human mouth at close quarters and complies with the Standards IEEE 269, 661 and ITU-T Rec. P51.
GRAS 44AB is for testing telephone mouthpieces as well as other microphones similarly used in communication networks.
Technology
GRAS 44AB and 44AB-1
At the mouth reference point (MRP), which is 25 mm from the detachable lip ring (35 mm from the mouth of the Type 44AB/AB-1), the maximum continuous signal it can produce in ⅓-octave bands is 100 dB re. 20 µPa in the frequency range of 100 Hz to 16 kHz. Its loudspeaker accepts an external signal directly via a BNC input.
Jigs are included for calibration according to CCITT P.51 and IEEE 269. These are for use with ¼″ or ½″ microphones. One jig holds the microphone at 0º incidence (¼″ only) to the sound source, the other at 90º incidence (¼″ or ½″).
44AB-1 and is a special version of 44AB with the BNC connector positioned on the opposite side for proper mounting on the GRAS 45CC Test Fixture.
NOTE: This type of mouth simulator can not be mounted inside a KEMAR head.
Specifications
Maximum continuous output level at MRP [200 Hz - 6 kHz] 110 dB re. 20 μPa
Maximum continuous output level at MRP [100 Hz - 16 kHz] 100 dB re. 20 μPa
Distortion 250 Hz - 8 kHz (Linear signal @ 94 dB at MRP) typically 1 %, max. 1.5 %
Frequency response
GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.
Dimensions
44AB
44AB-1
Ordering info
Included
GRAS RA0104 | Jig (CCITT P51) |
GRAS RA0105 | Jig (IEEE 269) |
AB0012 | 24 VDC Power supply |
Optional
GRAS RA0110 | Conical mouthpiece |
GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.
