主题：受话器的频响测试

Ear Simulator Type 4157

Ear Simulator Type 4157 is primarily intended for frequency response, sensitivity and distortion measurements on earphones coupled to the ear by ear inserts such as tubes, ear moulds or eartips, for example, as used in hearing aids and operator headsets.

The Ear Simulator consists of a main housing into which are assembled a number of rings whose shapes form annular air volumes connected to the main volume of the housing by air passages. The main ear canal volume is of a similar shape and volume to that of the actual human ear and provides similar acoustic impedance to the insert earphone being tested.

Features

• Conforms to IEC 711, ANSI S3.25, and ITU-T P.57 Type 2
• Can be used to perform hearing aid testing to IEC 118-0 and IEC 118-7
• Includes several insert-earphone adaptors
• Built-in ½” Microphone Type 4134
• Includes Preamplifier Type 2669, with individual calibration chart

Artificial Ears Types 4152 and 4153

Artificial Ears Types 4152 and 4153 have been designed for measurements in the audiometric and related fields. They enable electroacoustical measurements on either insert earphones or headphones to be carried out under well-defined acoustical conditions, which are of great importance for the comparability of different designs and the reproducibility of measurements.

The Artificial Ear consists of an acoustic coupler, a main housing containing the sockets for the connection of a Brüel & Kjær condenser microphone, and a baseplate with a mechanism for clamping the object being tested.

Features for 4152

• Conforms to IEC126, ANSIS3.7 - 1973, and NBS9A
• Used with 1” Microphone Type 4144 and Preamplifier Type 2669
• 2 cm³ Coupler DB0138, 6cm³ Coupler DB0161, and 6cm³ Coupler DB0909 for measurements on insert type hearing aids, earphones and headphones

Features for 4153

• Fulfils the requirements of IEC318
• Uses a ½” microphone and preamplifier
• 3-cavity coupler simulating the acoustic input impedance of a human ear
• Test cap and flat plate adaptor included

Artificial Mastoid Type 4930

Artificial Mastoid Type 4930 has been designed for the calibration of bone conduction hearing aids and bone vibrators used in audiometry. It consists of a mechanical simulation of the human head, incorporating a built-in force transducer to monitor the output of the device to be calibrated. All the components of the Artificial Mastoid have been selected to ensure both excellent long-term stability and accurate correspondence with the mechanical characteristics of the human mastoid.

The Artificial Mastoid consists of an inertial mass, simulating the human head, mounted on a baseplate by resilient plastic spacers which surround the securing-bolts. The baseplate is carried on a suspension composed of three conical springs filled with foam rubber to provide damping. The natural frequencies of this suspension, which isolates the whole apparatus from external disturbances such as someone bumping the table during use, are all below 5 Hz, which is one-tenth of the low-frequency limit of the working range.

Features

• Fulfils IEC373, BS4009, and ANSIS3.13 - 1972
• Simulates mechanical impedance of human mastoid
• Freq. range: 50Hz to 10kHz
• Adjustable static force from 2 to 8N
• Built-in force transducer to measure dynamic force and acceleration

Brüel & Kjær's Test Head, Mouth Simulator and Ear Simulators provide optimal conditions for objective and standardised telephone testing. These products combine the requirements for acoustical performance with those for practical use. Ear and Mouth Simulators Types 4185, 4195 and 4227 are for use in Telephone Test Head Type 4602B.

Ear Simulator Type 4185

Ear Simulator Type 4185 is designed for telephone measurements requiring an IEC318 coupler. This is suitable for measurements on high impedance earphones where sealed conditions are required.

Features:

• Conforms to IEC318 and ITU-T P.51 Type 1
• Built-in sound source for seal checking
• ½" microphone and preamplifier included 
• Individually calibrated (in accordance with ITU-T P.57)

Wideband Ear Simulator Type 4195

Wideband Ear Simulator Type 4195 has been designed to match the ear simulators in Head and Torso Simulator Type 4128C for measurements on telephone handsets. Type 4195 therefore provides a very realistic acoustical load to the telephone handset being tested and easily shows acoustic differences between telephone handsets as they appear in real use. This feature is vital when designing telephone handsets optimised for improved sound quality.

Features:

• Conforms to ITU-T P.51 Type 3.2
• Provide realistic acoustic load (both high and low leak versions)
• ½" microphone and preamplifier included 
• Individually calibrated (in accordance with ITU-T P.57)

Mouth Simulator Type 4227

Mouth Simulator Type 4227 is an accurate reference sound source developed for near field testing of telephone transmitters and microphones. It provides a standardised and realistic simulation of the human voice field.

Features:

• Conforms to IEEE-269, IEEE-661 and ITU-T P.51.
• Accurate level and frequency response calibration is easily done using a Brüel & Kjær ½" microphone placed in the supplied calibration jig
• Accurate simulation of human voice field
• Quality control testing of frequency response and distortion of telephone transmitters and close-talking microphones
• Continuous SPL of 100dB 25mm from lip ring
• Low distortion
• Built-in overload protection circuit