Wideband Ear Simulator Type 4987 Family
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PRODUCT DATA Wideband Ear Simulator Type 4987 Family High precision ear simulators for production line testing The Wideband Ear Simulator Type 4987 family includes a range of ear simulators designed for realistic and comparable quality control (QC) testing of earphones, ear buds, telephone handsets and headsets on high-volume production lines. There are three models: • Type 4987 (photo left) • Type 4987-A (photo centre) • Type 4987-B (photo right) Uses and Features Uses • Compliance testing on production lines • Testing during R&D • Quality assurance testing • Design based on ITU-T Rec. P.57 Type 2 ear simulator • Includes high-precision ½ microphone and constant current line drive (CCLD) preamplifier with TEDS and SMB connector • Easy calibration and verification • Fast and easy swap between different designs on the production line • Calibration data including acoustic transfer impedance, microphone response and sensitivity • Allows easy mounting of leakage adapters Description The Type 4987 family has been developed for production line quality control of insert, intra-concha (ear buds), supra-aural (on-ear), supra-concha (in-ear) and circum-aural (over-ear) earphone devices. Mating to the device under test (DUT) is done by means of standardized or customized adapters that are screwed onto the coupler. This innovative concept allows full measurement compatibility between the production line and the laboratory or verification department. The design of the ear simulator in Type 4987 is based on ITU-T Rec. P.57 Type 2 ear simulator. It consists of a main housing with built-in annular air volumes connected to the main volume by air passages. The acoustic input impedance simulates the average acoustic load of the inner part of the ear canal. This ensures proper acoustical performance and accurate absolute measurements of the DUT. A ½ highprecision prepolarized pressure-field microphone is mounted in the housing of the ear simulator, terminating the main ear canal volume. The microphone is connected to a CCLD microphone preamplifier, with TEDS, making it suitable for connection to a wide variety of conditioning equipment supplying CCLD power. The ear simulator is supplied with full calibration data, including: microphone response; sensitivity; transfer imped

Type 4987 Structure Type 4987 can be fitted with different types of simplified pinna simulators, supporting high-leak or low-leak performance, as well as with standard or customized adapters to make a perfect fit for the DUT. The product type number (4987-X-nnn) is structured in the following way: • 4987: specifies the occluded ear simulator coupler with a ½ microphone and CCLD preamplifier • -X: specifies different types of simplified pinna/concha simulators, as follows: --: No pinna/concha simulator A: High-leak pinna simulator with flange for telephone receivers B: High-leak concha base...

Calibration and Verification During manufacture, the ear simulator is calibrated according to ITU-T Rec. P.57. A comprehensive individual calibration data set is supplied, allowing easy frequency response correction for optimal performance. Supplied individual calibration data includes: • Microphone frequency response re 250 Hz • Acoustic transfer impedance • Sensitivity of the ear simulator at 250 Hz Fig. 2 Typical frequency response of the included pressure field microphone re. 250 Hz (dB) 4 2 0 Acoustic Transfer Impedance The acoustic transfer impedance is measured as the worst-case...

Fig. 4 Type 4987 – Typical low frequency response of Type 4969 microphone when mounted in Type 4987 re. 250 Hz (dB) 4 2 0 Fig. 5 Type 4987-B-x - Typical acoustic transfer impedance f dB re. 500 Hz 50 40 30 20 Fig. 6 Typical acoustic transfer impedance of Type 4987-A-x  f dB re. 500 Hz 60 50 40 30

Sensitivity Calibration Using Calibration Adapter DP-1079 The absolute sensitivity is verified by means of Sound Calibrator Type 4231 mounted with Calibration Adapter DP-1079, Fig. 7. Fig. 7 Performing a sensitivity check on a Type 4987-A-001 using Sound Calibrator Type 4231 with Calibration Adapter DP-1079 Using Calibration Adapter DP-1079 allows you to fit the ear simulator to Sound Calibrator Type 4231 without removing the adapter ring. DP-1079 has a correction factor of +6.0 dB when used in combination with Type 4231 in order to obtain the sensitivity at 250 Hz. Table 2 Types of...

Compliance with Standards The CE marking is the manufacturer's declaration that the product meets the requirements of the applicable EU directives RCM mark indicates compliance with applicable ACMA technical standards – that is, for telecommunications, radio communications, EMC and EME China RoHS mark indicates compliance with administrative measures on the control of pollution caused by electronic information products according to the Ministry of Information Industries of the People’s Republic of China WEEE mark indicates compliance with the EU WEEE Directive EN/IEC 61010–1: Safety...

Fig. 9 Coupler Dimensions – a) Type 4987, b) Type 4987-B-x, c) Type 4987-A-x

Ordering Information Type 4987 Wideband Ear Simulator (½ Microphone and CCLD Preamplifier) Consisting of: IEC 60318-4 (formerly IEC 60711) compliant coupler ½ High Precision Pressure Field Microphone, prepolarized ½ CCLD Microphone Preamplifier with TEDS 5  Dust protectors (DS-0535) Calibration chart TYPE 4987 CONFIGURATIONS Configuration Overview Item Pinna Simulator Wideband Ear Simulator (½ Microphone and CCLD Preamplifier) Wideband Ear Simulator (½ Microphone and CCLD Preamplifier) High-leak flange For modern smartphone receivers: x: 001 - circular x: 002 - semi-circular...