TR41.3.3-08-02-005-L-TIA-920A_HandsetFrequencyResponseMasks-Revisited,GHess,MWM

1、Telecommunications Industry AssociationTR41.3.3-08-02-005-LDocument Cover SheetProject NumberPN-3-4705-RV1 (TIA-920-A)Document TitleTIA 920-A Handset Send and Receive Frequency Response Masks - RevisitedSourceMWM AcousticsContactName: Glenn HessPhone:317-596-1721Complete Address:Suite 5206602 East 7

2、5th StreetIndianapolis, IN 46250Fax:317-849-8178Email:hessDistributionTR-41.3.3Intended Purpose of Document(Select one)XFor Incorporation Into TIA PublicationFor InformationOther (describe) - The document to which this cover statement is attached is submitted to a Formulating Group or sub-element th

3、ereof of the Telecommunications Industry Association (TIA) in accordance with the provisions of Sections .6 inclusive of the TIA Engineering Manual dated March 2005, all of which provisions are hereby incorporated by reference.AbstractThe TIA 920-A handset frequency response masks are being

4、revisited to show how the Draft 8 templates compare to current TIA 920 mandatory requirements. Also, one small change is proposed for the receive template based on measurement data shared in an earlier TIA contribution (TR.41.3.3-06-11-06L).This document recommends the upper receive template boundar

5、y be changed slightly across mid band frequencies. By adjusting the template window in the 700 to 1400 Hz region, this standard will be more accommodating to new wideband handset designs with varied response characteristics.The frequency response data referenced above is shown for three wideband han

6、dsets relative to TIA 920-A Draft 8 and the newly proposed template change. Two handsets are in production by Tier 1 companies and sold with wideband IP telephones. The third handset is a new design to be more leak tolerant.v1.0 20050426Current TIA 920-A Handset Masks with Nominal Responses -The gra

7、phs below show current 920 mandatory handset telephone requirements and the 920-A Draft 8 templates. The nominal wideband send and receive frequency responses found in 810-B Annex D were added for comparison.Current TIA 920-A Handset Masks with Measured Responses -The graphs below show 920-A Draft 8

8、 handset telephone requirements. Handset send and receive measured responses were added showing two current wideband products from Tier 1 manufacturers, and a development prototype incorporating a new mechanical design and leak tolerant receiver. These handsets represent different acoustic designs,

9、transducer types, and component suppliers.All handsets were measured on a B&K 4128 Head & Torso Simulator using the Type 3.3 ear simulator with hardness of 35 ±6 degrees Shore-OO. Handsets were positioned at the high leak position using a 10N force as defined in 810-B and TIA 920-A Draf

10、t 8. Send and receive frequency response measurements were made using a 1/12 octave (R40) sine wave sweep.Proposed TIA 920-A Handset Mask with Nominal Response -The current 920-A Draft 8 send mask remains the same and no changes are proposed. A small change is recommended for the Draft 8 receive mas

11、k. The upper limit transition from 1000 to 2000 Hz is being shifted to 700 and 1400 Hz. Opening the mask window in the mid band frequencies will be more accommodating to new leak tolerant handsets with different mechanical structures and transducer designs.Limit CurveFrequency(Hz)Mandatory Receive L

12、imit(dB) arbitrary levelUpper Limit100+1130+41000 (700)+42000 (1400)+94000+98000+8Lower Limit200- infinity200-10800-44000-46800-106800-infinityProposed TIA 920-A Handset Mask with Measured Responses -The graphs below show 920-A MWM proposed handset receive requirements with frequency responses for t

13、he three wideband handsets described above. This first graph displays receive responses from 100 to 8500 Hz using the 1/12 octave measurement resolution. The second graph uses 1/12 octave resolution from 100 to 3750 Hz, and the Draft 8 recommended 1/3 octave data points from 4000 to 8000 Hz.These test results show frequency response characteristics one can expect from wideband handsets measured with a Type 3.3 ear on HATS. Receive responses vary all over with noticeable peaks and dips. The lower