Telecommunications Industry Association
TR41.3.14-14-08-004
Document Cover Sheet
Project Number
ANSI/TIA-1083-A
Document Title
Analog HAC with Active Speech
Source
Industry Canada
Contact
Name: Jason Nixon
Complete Address: 3701 Carling Ave,
Building 94, Ottawa, ON, K2H 8S2
Distribution
TR-41.3.14
Intended Purpose
of Document
(Select one)
X
Phone: 613-990-6551
Fax:
Email: Jason.nixon@ic.gc.ca
For Incorporation Into TIA Publication
For Information
Other (describe) -
The document to which this cover statement is attached is submitted to a TIA Engineering
Committee, Formulating Group, or sub-element thereof in accordance with the provisions of TIA
procedures including but not limited to Section 3.3.2 of the TIA Engineering Committee Operating
Procedures, all of which provisions are hereby incorporated by reference.
Abstract
A small study was carried out on how the use of an IEEE active speech signal could be used to measure
HAC on analog telephones and how it would compare to the traditional swept sinewave method.
V2.0 – 20140702
Telecommunications Industry Association
TR41.3.14-14-08-004
Measurement description
All measurements were carried out on cordless DECT telephones.
HAC frequency response was measured using the existing swept sinewave
HAC frequency response was repeated using the IEEE real male speech pattern, set to a level of 19dBV, and averaged over the 1/12th octaves to create a frequency response. The measured
values were weighted with a response curve of the IEEE real speech pattern to flatten the
response for comparison to the traditional HAC frequency response curve.
Measurement results
Real Speech Weighting
15
10
5
0
-5
-10
300
3000
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Telecommunications Industry Association
TR41.3.14-14-08-004
Phone 1
15
10
5
Upper Limit
0
300
3000
-5
Lower Limit
Swept Sinewave
Real Speech
-10
-15
-20
Phone 2
15
10
5
Upper Limit
0
300
3000
-5
Lower Limit
Swept Sinewave
Real Speech
-10
-15
-20
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Telecommunications Industry Association
TR41.3.14-14-08-004
Phone 3
15
10
5
Upper Limit
0
300
3000
-5
Lower Limit
Swept Sinewave
Real Speech
-10
-15
-20
Phone 4
15
10
5
Upper Limit
0
300
3000
-5
Lower Limit
Swept Sinewave
Real Speech
-10
-15
-20
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Telecommunications Industry Association
TR41.3.14-14-08-004
Phone 5
15
10
5
Upper Limit
0
300
lower Limit
3000
Swept Sinewave
-5
Real Speech
-10
-15
-20
Deviation between methods
Frequency
Handset
1
Handset
2
Deviation
Handset
3
Handset
4
Handset
5
300
1.44
0.59
0.64
1.02
4.05
378
0.65
-0.32
-0.3
0.31
2.56
476
-0.07
-0.94
-0.89
0.09
1.12
600
0.62
0.37
0.19
-0.08
0.56
756
-0.4
0.32
-0.41
-0.06
0.04
953
0.49
0.24
0.42
0.2
0.51
1000
0.19
0.33
0.16
0.37
-0.09
1260
0
-0.05
0.12
-0.03
0.32
1588
0.18
-0.39
-0.48
0.14
1.26
2000
0.14
0.32
-0.23
0.14
2.3
2520
3
0.71
1.2
0.69
2.26
3176
2.82
0.1
0.96
0.42
3.01
3300
2.25
0.32
1.05
0.98
1.12
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Telecommunications Industry Association
TR41.3.14-14-08-004
Measurement observations
-
The largest deviations occur at the low and high frequency points.
The correction shape has a large null at the low frequency and a quick null at the high
frequency.
The general response of both the real speech and swept sinewave is similar for all phones.
The measurement points did not exactly match since the discrete sinewave frequency and
the 1/12th octave frequency are not the same.
Conclusions
-
-
-
The deviation observed in this study would indicate that the real speech pattern HAC
Frequency response is not a suitable replacement for the traditional swept sinewave
method.
The correction used for the IEEE real speech was a single measurement of the IEEE real
male speech pattern. An attempt was made to average multiple measurement results but
it was found that the correction did not change. More investigation would be required
into an appropriate correction shape.
The axial (or radial) HAC level could be determined if the 1/12th octave encompassing 1
kHz was properly corrected for the input level of the real speech with relation to the
traditional 1 kHz sinewave and the sensitivity of the HAC probe.
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