Telecommunications Industry Association
TR41.3.14-14.02-005
Document Cover Sheet
Project Number
ANSI/TIA-PN-1083-B
Document Title
Handset Magnetic Measurement Procedures and Performance Requirements.
Source
Don McKinnon
Contact
Don McKinnon
1430 Sarno Rd
Melbourne, FL 32935
Distribution
TR-41.3.14
Intended Purpose
of Document
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Phone: 321-254-8118
Fax: 321-254-9511
Email: dmckinnon@asttechlabs.com
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 October 2009, all
of which provisions are hereby incorporated by reference.
Abstract
This contribution provides information regarding five analog cordless telephones HAC Perpendicular
field intensity (FI) when tested with a 1 kHz tone vs. speech and the impact on SNR.
INFORMATION & DATA
1. Perpendicular field intensity data with tones and speech for 5 cordless phones is provided in the
following tables.
a) Units A, B & C are newer design models.
b) Unit D is an older unit designed before TIA-1083 was published.
c) Unit E is an older model that may no longer be in production but was produced after TIA1083 was published.
Phone
FI 1 kHz
FI Male
Tone
Tone
Speech Speech
SNR
SNR
(-16 dBV)
(-16 dBV)
Volume
setting
Noise
level
Minimum
-41.7
-3.3
38.4
-7.5
34.2
Maximum -41.7
13.2
54.9
2.4
44.1
A
VC delta
(dB)
0.0
16.5
-
9.9
-
Minimum
-40.8
-0.8
40.0
-5.1
35.7
Maximum -40.8
14.2
55.0
4.5
46.3
VC delta
(dB)
15.0
-
9.6
-
B
0.0
1
Comments
Existing 45 dB SNR requirement was not
met with -16 dBV Speech.
The magnetic output with speech for most
volume controls was not linear but was
linear with tones.
The existing 45 dB SNR requirement was
met with Speech.
The magnetic output with speech for most
volume controls was not linear but was
linear with tones.
Telecommunications Industry Association
Phone
TR41.3.14-14.02-005
FI 1 kHz
FI Male
Tone Speech Speech
Tone
SNR
SNR
(-16 dBV)
(-16 dBV)
Volume
setting
Noise
level
Minimum
-44.8
-5.9
38.9
-10.8
34.0
Maximum -44.8
9.2
54.0
-2.0
42.8
C
VC delta
(dB)
0.0
15.1
-
8.8
-
Minimum
-41.7
-10.9
30.8
-16.0
25.7
3.5
45.1
-4.0
37.6
Maximum -41.6
D
VC delta
(dB)
0.1
14.4
-
12.0
-
Minimum
-45.4
-2.2
43.2
-5.6
39.8
Maximum -45.5
15.0
60.5
9.6
55.1
17.2
-
15.2
-
E
VC delta
(dB)
0.1
Comments
Existing 45 dB SNR requirement was not
met with -16 dBV Speech.
The magnetic output with speech for most
volume controls was not linear but was
linear with tones.
Existing 45 dB SNR requirement was not
met with -16 dBV Speech.
The magnetic output with speech for the
maximum volume control was not linear
but was linear with tones.
Existing 45 dB SNR requirement was met
with -16 dBV Speech. High magnetic
output signal exhibited
The magnetic output with speech for the
maximum volume control was not linear
but was linear with tones.
2. Phones C, D and E were retested with an average -28 dBV speech input level:
Phone
FI 1 kHz
FI Male
Tone
Tone
Speech Speech
SNR
SNR
(-16 dBV)
(-28 dBV)
Volume
setting
Noise
level
Minimum
-44.8
-5.9
38.9
-21.5
23.3
Maximum -44.8
9.2
54.0
-6.5
38.3
C
VC delta
(dB)
0.0
15.1
-
15.0
-
Minimum
-41.7
-10.9
30.8
-27.1
14.6
3.5
45.1
-13.0
28.7
Maximum -41.6
D
VC delta
(dB)
0.0
14.4
-
14.1
-
Minimum
-45.4
-2.2
43.2
-17.6
27.8
Maximum -45.5
15.0
60.5
-0.6
44.9
E
VC delta
(dB)
0.1
17.2
-
17.0
2
-
Comments
Existing 45 dB SNR requirement was not
met with -28 dBV Speech.
The magnetic output for all the volume
controls was linear for speech (15.0 dB
range)
Existing 45 dB SNR requirement was not
met with -28 dBV Speech.
The magnetic output for all the volume
controls was linear for speech (14.0 dB
range)
Existing 45 dB SNR requirement was not
met with -28 dBV Speech.
The magnetic output for all the volume
controls was linear for speech (17.0 dB
range)
Telecommunications Industry Association
TR41.3.14-14.02-005
DATA REVIEW
1. The FI volume control range for three phones (A, B, C) exhibited ≥ 5.4 dB difference when
comparing the -16 dBV speech output levels to the -16 dBV tones output levels. It is not known what
the acoustic output gain for these units would be, but they do have FCC numbers and it is assumed
that the FCC volume control requirements are met (12 – 18 dB).
2. Two of the 5 phones (B & E) met the existing 45 dB SNR requirement with -16 dBV speech.
3. With the minimum volume control setting, the magnetic FI output for the -16 dBV speech input vs.
the -16 dBV tone input averaged 4.4 dB lower (5.1 to 3.4 dB range)
4. Three phones (C, D & E) retested with -28 dBV speech input level did not meet the existing 45 dB
SNR requirement.
5. Assuming units A & B exhibited linearity with input level and magnetic output with a -28 dBV input
speech level, they would not meet the existing 45 dB SNR requirement (see table below).
Phone
A
B
Volume
setting
Noise
level
FI 1 kHz Tone FI Male Speech
Tone
SNR Speech
SNR
(-16 dBV)
(-28 dBV)
Minimum
-41.7
-3.3
38.4 -19.5 (-7.5)
Maximum -41.7
13.2
54.9
-3.0 (2.4)
38.7
-
16.5
-
22.2
VC delta
(dB)
0.0
16.5
Minimum
-40.8
-0.8
40.0 -17.1 (-5.1)
Maximum -40.8
14.2
55.0
-2.1 (4.5)
38.7
VC delta
(dB)
15.0
-
15.0
-
0.0
23.7
Comments
The existing SNR requirement would not
be met with -28dBV Speech.
Assuming linear operation with input
level and magnetic output level
The existing SNR requirement would not
be met with -28dBV Speech.
Assuming linear operation with input
level and magnetic output level
WRAP-UP
1. In Annex D (Cordless Phone/Hearing Aid Telecoil Mode Signal-to-Noise Study), sub-clause D.4
(Test Results), it stated that with speech a minimum 30 dB SNR was required to achieve an 80%
“normal use” rating for cordless phone modulation-related noise types.
Minimum S/N for a "Normal Use" Rating
50
S/N - dB
40
30
DSSS
FHSS
20
Display
10
0
0%
20%
40%
60%
subjects meeting criteria
3
80%
100%
Telecommunications Industry Association
TR41.3.14-14.02-005
2. It also stated in Annex D:
In this study, all test signals were referenced to the input of a subject’s hearing aid. Speech and noise
levels and frequency responses were carefully controlled and normalized relative to the signals applied
to the hearing aid. When interpreting the speech levels and resultant S/N results, it should be kept in
mind that the speech levels are average levels, as discussed below. It is recognized in FCC Part 68.316
that the test signal specified there and in this standard will result in a receiver output that is
approximately 15 dB above typical average speech levels that the phone would produce in the field.
Thus, S/N ratios reported in this study correspond to ratios as measured in this standard that are
typically 15 dB higher.
3. With a -16 dBV speech input level all phones tested would meet a 30 dB SNR requirement with a
minimum margin of 7.6 dB. However -16 dBV would not represent the average input level to a
phone.
4. With an average speech input level of -28 dBV, 2 of the 3 phones (C, D & E) retested with -28 dBV
input level would meet a 30 dB SNR. Assuming linear operation the other 2 units (A & B) also
would meet a 30 dB SNR requirement. The one unit (D) that would not meet a 30 dB SNR
requirement is an older unit designed before TIA-1083 was published.
5. If Speech is to be considered for FI on units that do not test well with tones, then a 30 dB SNR
requirement with average speech input level of -28 dBV for analog (and -20 dBm0 for digital) should
be utilized.
4