Telecommunications Industry Association
TR41.3.10-08-02-007-L
Document Cover Sheet
Project Number
Vtech Contribution on TR41.3.10 (TIA 470.120-C)
Receive Level
Document Title
Source
Contact
Distribution
Intended Purpose
of Document
(Select one)
VTech Communications
Michael Chen
200-7671 Alderbridge Way, Richmond,
BC V6x 1Z9
Phone: (604) 273 -5131
Fax:
Email: michaelchen@vtech.ca
TR-41.3.10
X
For Incorporation Into TIA Publication
For Information
Other (describe) -
The document to which this cover statement is attached is submitted to a Formulating Group or
sub-element thereof of the Telecommunications Industry Association (TIA) in accordance with the
provisions of Sections 6.4.1–6.4.6 inclusive of the TIA Engineering Manual dated March 2005, all of
which provisions are hereby incorporated by reference.
Abstract
This document is to provide the measurement of Receive Level on –15dBV at 0km, -27dBV at
2.7km and –39dBV at 4.6km for the 5 base unit speakerphones. The document suggests that
“should be” requirement be used instead of “shall be” requirement for the Receive Level
measurement.
.
v1.0 – 20050426
Telecommunications Industry Association
TR41.3.10-08-02-007-L
1. Speaker phone Samples Description and Test setup
This is to provide the measurement data on Speech level measurement on
Sample #1 and #5: corded line powered speakerphone
Sample #2 to #4: corded AC powered speakerphone
2. Test Setup
Stimulus signal level at the generator (measured with a matched load):
-15dBV at 0km
-27dBV at 2.7km
-39dBV at 4.6km
The measurement is done in an anechoic chamber, the ITU-T P.50 female + male
artificial voice was used.
3. Test Data
Line-Powered
Input Level Artificial Line
AC Powered
Draft 14 Spec.
sample # 1
sample # 5 sample # 3 sample # 4 sample # 2
Shall be
dBSPL
RX Level
(dBSPL)
RX Level
(dBSPL)
RX Level
(dBSPL)
RX Level
(dBSPL)
RX Level
(dBSPL)
-15dBV
0km
≥ 73
72.93
69.29
77.35
71.27
80.92
-27dBV
2.7km
≥ 73
63.04
60.71
64.53
60.05
71.79
-39dBV
4.6km
≥ 58
51.62
50.5
52.05
49.69
59.22
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Telecommunications Industry Association
TR41.3.10-08-02-007-L
4. Suggestion
In “TR41.3.10-08-02-003-SpeakerphoneDraft14.doc”, the requirement for the Receive
Level is shown as following
Draft 14 Specification
Input Level
-15dBV
-27dBV
-39dBV
Artificial Line
0km
2.7km
4.6km
Shall be dBSPL
≥ 73
≥ 73
≥ 58
If combining the data from “TR41.3.10-07-11-004-SpeakerphoneReceiveLevelTesting,
DMcKinnon, AST.pdf” with the Vtech measurement, it can be found that:
7/17 samples failed the –15dBV at 0km requirement
16/17 samples failed the –27dBV at 2.7km requirement
14/17 samples failed the –39dBV at 4.6km requirement.
Based on these test results, the most of the speakerphone in the market will failed this
requirement.
Due to the fact that the sound level measurement is done in an Anechoic Chamber, in
which there is only a test table inside (152cm by 76cm). In the actual usage
environment, there is more reflection than that in an anechoic chamber, so the
speakerphone can be subjectively heard louder in a normal usage environment.
Vtech suggests to change to “should be” requirement instead of “shall be” requirement
for the speakerphone Receive Level measurement.
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