TR41.3.3-01-08-018
STANDARDS PROJECT
TITLE
SOURCE
CONTACT
DATE
DISTRIBUTION
PN-4705
IEEE 269-2001 Reference Inserts
MWM Acoustics, LLC
Suite 520
6602 E. 75th Street
Indianapolis, IN 46250
Glenn R. Hess
Phone: 317-596-1721
Fax: 317-849-8178
Email: hess@mwmacoustics.com
August 17, 2001
TIA TR-41.3.3 Subcommittee
This contribution provides recommendations for inserting references of IEEE 269-2001
Draft 8.1, “Standard Methods for Measuring Transmission Performance of Analog and
Digital Telephone Sets, Handsets and Headsets” into TIA PN-4705 Draft 5. The
“Measurement Method” clauses in TIA PN-4705 sections 5 and 6 have been modified to
incorporate references to IEEE 269 test procedures where appropriate. This was done to
improve the clarity and consistency of the measurement procedures. Please consider these
remarks in your development of this wideband digital wireline telephone specification.
Additional Contributions from John R. Bareham (734-665-4224, jbareham@mich.com)
NOTICE: The proposals in this submission have been formulated to assist Subcommittee TIA TR-41.3.3.
This document is offered to the subcommittee as a basis for discussion and is not binding on MWM
Acoustics. MWM Acoustics specifically reserves the right to add to, or amend, the quantitative statements
made herein. Nothing contained herein shall be construed as conferring by implication, estoppel, or
otherwise any license or right under any patent, whether or not the use of information herein necessarily
employs an invention of any existing or later issued patent.
COPYRIGHT NOTICE: The contributor grants a free, irrevocable license to the Telecommunications
Industry Association (TIA) to incorporate text contained in this contribution and any modifications thereof
in the creation of a TIA standards publication; to copyright in TIA’s name any standards publication even
though it may include portions of this contribution; and, at TIA’s sole discretion, to permit others to
reproduce in whole or in part the resulting TIA standards publication.
Glenn R. Hess
MWM Acoustics
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References to IEEE Std. 269-2001 for TIA/EIA PN-4705, Draft 5
I recommend that the text below be added to the clauses of TIA/EIA PN-4705 Draft 5.
Refer to Clause 8.1 in IEEE Std 269-200x for general information on testing methods, especially test
signals and volume control settings.
Explanations & recommendations:
IEEE 269 is only defined to 8000Hz. (Draft 8.1 is not consistent, but that will be corrected.)
In receive direction, the limit is 8500Hz, or the 8659Hz 1/12 octave band, since these are the limits of the
correction curves supplied for ear simulators. See Annex B. In send direction, limit is the 7718 Hz. 1/12
octave band, since this is the upper limit of artificial speech (ITU-T P.50), which is the standard test signal
in IEEE 269. (Sines may be used if it can be shown that there is no adaptive or nonlinear processing in the
phone, but such evidence must be submitted in the test report.) See clause 8.1.1.
Recommendation: Use “100-8000Hz” throughout.
Reference receive (and send) volume control settings are defined and required for measurements. The
definitions in 269 are intended to cover the widest possible range of telephone (as well as headset) design.
Recommendation: Use “reference volume control setting(s)” throughout.
Recommendation: Place receive before send, an in 269, since that is the order in which reference volume
control setting must be determined.
Recommendation: Search the entire draft for cunfusion regarding implied use of sinewaves, when artificial
speech is the default test signal. Refer to “ISO R40” only when it specifically refers to sine stimulus. Use
“1/12 octave bands” when referring to artificial speech, noise, or other continuous-band signals.
5. Handset Technical Requirements
Addition:
Refer to Clause 5.1 and Annex C.1 in IEEE Std 269-2001 for details on ear simulators and their
use, and Clause 5.2 and Annex C.2 in IEEE Std 269-2001 for details on mouth simulators and
their use.
5.1.1 Handset Send Frequency Response
5.1.1.1 Measurement Method
Current:
The send frequency response is measured according to ITU-T Recommendation P.64 using the
measurement set-up shown in Figure 3. Direct digital processing may be employed as explained
in section 4.9. The test signal level shall be -4.7 dBPa at the MRP.
Replacement:
The send frequency response shall be made in accordance with the methods described in Clause
8.5.1 of IEEE Std 269-2001 using the measurement set-up shown in Figure 3. Direct digital
processing may be employed as explained in section 4.9. The test signal level shall be -4.7 dBPa
at the MRP.
Equation [1] has a form different from the corresponding Equation 14 in IEEE 269, but the effect
is the same. (Repeat similar note in similar instances in the draft.)
5.1.2 Handset Receive Frequency Response
5.1.2.1 Measurement Method
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Current:
Mount the handset with the receiver coupled to the ear simulator. The receive frequency response
is measured according to ITU-T Recommendation P.64 using the measurement set-up shown in
Figure 5. Direct digital processing may be employed as explained in section 4.9.
Replacement:
Mount the handset with the receiver coupled to the ear simulator. The receive frequency response
shall be made in accordance with the methods described in Clause 8.4.1 of IEEE Std 269-2001
using the measurement set-up shown in Figure 5. Direct digital processing may be employed as
explained in section 4.9.
Equation [2] has a form different from the corresponding Equation 12 in IEEE 269, but the effect
is the same.
5.2.1.
Handset Wideband Send Loudness Rating (SLRw)
Current
The SLRw for a digital telephone set is the conversion ratio of a defined acoustic signal at the
mouth reference point to the transmit signal at the digital reference point. Refer to Annex A and
ITU-T Recommendation P.79.
Replacement:
The SLRw for a digital telephone set represents the perceived loss from the acoustic signal at the
mouth reference point to the send signal at the digital reference point. Refer to Annex A and ITUT Recommendation P.79.
(Replace similar instances elsewhere in draft.)
5.2.3 Handset Talker Sidetone
5.2.3.1 Measurement Method
Current:
Mount the handset in the HATS position with the receiver coupled to the artificial ear. The test
signal level at the MRP shall be -4.7 dBPa. For each frequency given in Table 9, bands 1 to 20,
the sound pressure in the artificial ear shall be measured.
Replacement:
Mount the handset in the HATS position with the receiver coupled to the artificial ear. The test
signal level at the MRP shall be -4.7 dBPa. For each frequency given in Table 9, bands 1 to 20,
the sound pressure in the artificial ear shall be measured in accordance with the methods
described in Clause 8.6.1 of IEEE Std 269-2001.
5.3.1 Handset Overall Send Noise
5.3.1.2 Measurement Method
Current:
With the handset in the HATS position with the receiver coupled to the artificial ear in a quiet
environment (ambient noise less than 30 dBA), measure the [@@@ A weighted noise level at the
digital interface output or the reference codec decoder output.
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Replacement:
Place the handset in the HATS position with the receiver coupled to the artificial ear in a quiet
environment (ambient noise less than 30 dBA). Measure the A-weighted noise level at the digital
interface output or the reference codec decoder output in accordance with the methods described
in Clause 8.5.2 of IEEE Std 269-2001.
5.3.2 Handset Send Single Frequency Interference
5.3.2.2 Measurement Method
Current:
With the handset in the HATS position and the receiver coupled to the ear simulator in a quiet
environment (ambient noise less than 30 dBA), measure the A-weighted noise level at the digital
interface output or the reference codec decoder output with an effective bandwidth of not more
than 31 Hz, over the frequency range of 150 to 6800 Hz. If FFT analysis is used, then “Flat Top”
windowing shall be employed.
Replacement:
Place the handset in the HATS position with the receiver coupled to the artificial ear in a quiet
environment (ambient noise less than 30 dBA). Measure the A-weighted noise level at the digital
interface output or the reference codec decoder output in accordance with the methods described
in Clause 8.5.3 of IEEE Std 269-2001.
5.3.3 Handset Overall Receive Noise
5.3.3.2 Measurement Method
Current:
The handset is mounted in the HATS position and the receiver coupled to the ear simulator. A
signal corresponding to a decoder value quiet code is applied at the digital interface. The Aweighted noise level is measured in the artificial ear. The ambient noise for this measurement
shall not exceed 30 dBA.
Replacement:
The handset is mounted in the HATS position and the receiver coupled to the ear simulator. A
signal corresponding to a decoder value quiet code is applied at the digital interface. The Aweighted noise level is measured in accordance with the methods described in Clause 8.4.2 of
IEEE Std 269-2001. The ambient noise for this measurement shall not exceed 30 dBA.
5.3.4 Handset Receive Single Frequency Interference
5.3.4.2 Measurement Method
Current:
The handset is mounted in the HATS position and the receiver coupled to the artificial ear. A
signal corresponding to a decoder quiet code is applied at the digital interface. The A-weighted
noise level is measured in the artificial ear with a selective voltmeter or spectrum analyzer, with
an effective bandwidth of not more then 31 Hz, over the frequency range of 100 to 10000 Hz. If
FFT analysis is used, then “Flat Top” windowing shall be employed. The ambient noise for this
measurement shall not exceed 30 dBA.
Replacement:
The handset is mounted in the HATS position and the receiver coupled to the artificial ear. A
signal corresponding to a decoder quiet code is applied at the digital interface. The A-weighted
noise level is measured in accordance with the methods described in Clause 8.4.3 of IEEE Std
269-2001. The ambient noise for this measurement shall not exceed 30 dBA.
5.5.1 Handset Send Distortion and Noise
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5.5.1.1 Method of Measurement
Current:
The handset is mounted in the HATS position and the receiver coupled to the ear simulator. The
distortion and noise is measured according to IEEE 1329, 9.3.6. Apply a sinewave signal at the
MRP, with the levels given in Table 3 and the following frequencies: 315, 502, 803, 1004, 2008
and 3150 Hz. The ratio of the signal-to-total distortion and noise power of the digitally encoded
signal output is measured [@@@ with A-weighted filtering?]. The test frequency tolerance is
3%, but even submultiples of the sampling frequency must not be used.
Replacement:
The handset is mounted in the HATS position and the receiver coupled to the ear simulator. The
distortion and noise is measured in accordance with the methods described in Clause 8.5.5 and
Annex H.4 of IEEE Std 269-2001. Apply a signal at the MRP, with the levels given in Table 3
and centered at the following frequencies: 160, 315, 502, 803, 1004, 2008 and 3150 Hz. The test
frequency tolerance is 3%, but even submultiples of the sampling frequency must not be used.
(Remark: Search the document to find and replace passages that imply use of sinewaves, when
some other signal is actually preferred or required. Sinewaves may not be suitable for this test.
Annex H has guidance.)
5.5.2 Handset Receive Distortion and Noise
5.5.2.1 Method of Measurement
Current:
The handset is mounted in the HATS position and the receiver coupled to ear simulator. The
distortion and noise is measured according to IEEE 1329, 9.4.6. Apply a sine wave test signal or
digital bit steam equivalent at the digital reference point, with the levels given in Table 4 and the
following frequencies: 160, 315, 502, 803, 1004, 2008 and 3150 Hz. The ratio of signal-to-total
distortion and noise power is measured with A-weighted filtering. The test frequency tolerance is
3%, but even submultiples of the sampling frequency must not be used.
Replacement:
The handset is mounted in the HATS position and the receiver coupled to ear simulator. The
distortion and noise is measured in accordance with the methods described in Clause 8.4.5 and
Annex H.4 of IEEE Std 269-2001. Apply a test signal or digital bit steam equivalent at the digital
reference point, with the levels given in Table 4 and centered at the following frequencies: 160,
315, 502, 803, 1004, 2008 and 3150 Hz. The test frequency tolerance is 3%, but even
submultiples of the sampling frequency must not be used.
5.6 Weighted Terminal Coupling Loss (TCLw)
5.6.1 Measurement Method
Current:
The attenuation from digital input to digital output is measured at 1/12 octave frequencies as
given by the R.40-series of preferred numbers in ISO 3 for frequencies from 160 to 6700 Hz,
using the measurement arrangement shown in Figure 7. See Annex C.
Replacement:
The attenuation from digital input to digital output is measured in accordance with the methods
described in Clause 8.8 of IEEE Std 269-2001. Testing is conducted using the measurement
arrangement shown in Figure 7. See Annex C.
(Remark: IEEE 269 clause 8.8 recommendss the use of CSS for echo testing. Sinewaves do not
give reliable results for most echo cancellation algorithms.)
Glenn R. Hess
MWM Acoustics
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5.7 Stability Loss
5.7.1 Measurement Method
Current:
The stability measurement shall be made at an input signal level of -16 dBm0, at 1/12 octave
bands centered at 205 Hz to 3868 Hz. The test signal is white noise, band limited to 100 through
7000 Hz, and modulated at a rate of 250 ms ON and 150 ms OFF. The measurement and
calibration shall be determined during the ON portions of the signal. Sine wave signals may be
used with linear PCM. With the handset and transmission circuit fully active, measure the
attenuation from the digital input to the digital output using Method 1 and Method 2. See Annex
C.
Replacement:
The stability measurement shall be made at an input signal level of -16 dBm0, at 1/12 octave
bands centered at 205 Hz to 3868 Hz. The test signal is white noise, band limited to 100 through
7000 Hz, and modulated at a rate of 250 ms ON and 150 ms OFF. The measurement and
calibration shall be determined during the ON portions of the signal. Sine wave signals may be
used with linear PCM. With the handset and transmission circuit fully active, measure in
accordance with the methods described in Clause 8.9 of IEEE Std 269-2001 using Method 1 and
Method 2. See Annex C.
Recommendations:
1.
Stability loss is essentially the same as echo, except for the test geometry. Suggest
rewording accordingly.
2.
Either adopt the methods of IEEE 269, specifically using CSS, or state some rule whereby
sinewaves may be used as an alternative. One way would be to allow sinewaves if evidence can
be given that the set unser test is linear and without echo cancelling algorithm. The nature of the
evidence can be left to the testing lab.
5.8 Long Duration Maximum Acoustic Pressure (Steady State Input)
5.8.2 Measurement Method
Current:
The steady-state A-weighted sound pressure level shall be measured using the digital terminals
test procedure in ITU-T Recommendation P.360, with the following modifications.
Replacement:
The steady-state A-weighted sound pressure level shall be measured using the digital terminals
test procedure in accordance with the methods described in Clause 8.12.1 of IEEE Std 269-2001,
with the following modifications.
5.9 Short Duration Maximum Acoustic Pressure (Peak)
5.9.2 Measurement Method
Current:
The peak acoustic pressure level shall be measured using the digital terminals test procedure in
ITU-T Recommendation P.360, with the following modifications instead of applying electrical
impulses to the send and receive pairs. The short duration acoustic pressure shall be determined
by applying digital codes to the receive input. The codes shall be switched between the maximum
positive and the maximum negative values, defined in Section 4.7. The switching rate shall range
from 2 Hz to 7000 Hz. The duration of the ON codes shall be a number of complete cycles
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approximating but not exceeding 500 ms. The ON codes must be followed by a quiet interval of
at least 500 ms before repeating the codes, as shown in Figure 9.
Replacement:
The peak acoustic pressure level shall be measured using the digital terminals test procedure in
accordance with the methods described in Clause 8.12.2 of IEEE Std 269-2001, with the
following modifications.
The short duration acoustic pressure shall be determined by applying digital codes to the receive
input. The codes shall be switched between the maximum positive and the maximum negative
values, defined in Section 4.7. The switching rate shall range from 2 Hz to 7000 Hz. The duration
of the ON codes shall be a number of complete cycles approximating but not exceeding 500 ms.
The ON codes must be followed by a quiet interval of at least 500 ms before repeating the codes,
as shown in Figure 9.
5.10.1 Handset Send Latency
5.10.1.2 Measurement Method
Current:
An acoustic signal of –4.7 dBPa should be generated at the mouth simulator. The delay between
the time the pulse left the mouth to the time it was received at the telephone’s network interface
should be measured.
Replacement:
An acoustic signal of –4.7 dBPa should be generated at the mouth simulator. The delay between
the time the pulse left the mouth to the time it was received at the telephone’s network interface
should be measured in accordance with the methods described in Clause 8.5.6 of IEEE Std 2692001.
5.10.2 Handset Receive Latency
5.10.2.2 Measurement Method
Current:
A pulsed digital signal of –16 dBm0 should be injected as packets to the telephone’s network
interface. The delay between the time the packet was injected at the telephone network interface
to the time it was received at the artificial ear should be measured.
Replacement:
A pulsed digital signal of –16 dBm0 should be injected as packets to the telephone’s network
interface. The delay between the time the packet was injected at the telephone network interface
to the time it was received at the artificial ear should be measured in accordance with the methods
described in Clause 8.4.6 of IEEE Std 269-2001.
6. Headset Technical Requirements
Addition:
Refer to Clause 5.1 and Annex C.1 in IEEE Std 269-2001 for details on ear simulators and their
use, and Clause 5.2 and Annex C.2 in IEEE Std 269-2001 for details on mouth simulators and
their use. Refer especially to Clause 5.2.3 1 in IEEE Std 269-2001 for headset positioning.
See added remarks from Clause 5, most of which apply to Clause 6 (JRB).
6.1.1 Headset Send Frequency Response
6.1.1.1 Measurement Method
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Current:
The send frequency response is measured according to IEEE 269 (200x).,. The test signal level
shall be -4.7 dBPa at the MRP over a minimum range of 100 Hz through 8000 Hz with ISO 1/12
octave intervals or smaller. Measurements should be done at RTP (Recommend Test Position
from manufacturer). If RTP is not available BMP (Boom Microphone Position) or STP (Standard
Test Position) shall be used.
Replacement:
The send frequency response shall be made in accordance with the methods described in Clause
8.5.1 of IEEE Std 269-2001. The test signal level shall be -4.7 dBPa at the MRP over a minimum
range of 100 Hz through 8000 Hz. Measurements should be done at RTP (Recommend Test
Position from manufacturer). If RTP is not available BMP (Boom Microphone Position) or STP
(Standard Test Position) shall be used.
6.1.2 Headset Receive Frequency Response
6.1.2.1 Measurement Method
Current:
The receive frequency response is measured according to IEEE 269 (200x). Measurements should
be done in ISO 1/12 octave intervals or smaller, over a minimum range of 100 Hz through 8000
Hz. Couple the receiver to the appropriate ear simulator. The test signal level shall be -18.2 dBV
(-16 dBm0). Telephone sets with adjustable receive levels shall be adjusted so that their RLR is
as close as possible to the nominal value of Section 5.2.2.2 for this test.
Replacement:
The receive frequency response shall be made in accordance with the methods described in
Clause 8.4.1 of IEEE Std 269-2001. Measurements should be done over a minimum range of 100
Hz through 8000 Hz. The test signal level shall be -18.2 dBV (-16 dBm0). Telephone sets with
adjustable receive levels shall be adjusted so that their RLR is as close as possible to the nominal
value of Section 6.2.2.2 for this test.
6.2.2 Headset Receive Loudness Rating
6.2.2.1 Measurement Method
Current:
The headset is mounted as specified by IEEE 269 (200x) and the receiver is coupled to the
appropriate ear simulator. The RLR shall be calculated from the 1/3 octave sensitivity data
collected from the receive frequency response measurement. Use equation [A2] of Annex A and
bands 4 to 17, Table 9.
Replacement:
The RLR shall be calculated from the 1/3 octave sensitivity data collected from the receive
frequency response measurement. Use equation [A2] of Annex A and bands 4 to 17, Table 9.
6.2.3 Headset Talker Sidetone
6.2.3.1 Measurement Method
Current:
The headset is mounted as specified by IEEE 269 (200x) and the receiver is coupled to the
appropriate ear simulator. The test signal level at the MRP shall be -4.7 dBPa. For each frequency
given in Table 9, bands 1 to 20, the sound pressure in the ear simulator shall be measured. The
STMR shall be calculated using equation [A3] of Annex A.
Replacement:
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The headset is mounted on HATS and the receiver is coupled to the appropriate ear simulator.
The test signal level at the MRP shall be -4.7 dBPa. For each frequency given in Table 9, bands 1
to 20, the sound pressure in the ear simulator shall be measured in accordance with the methods
described in Clause 8.6.1 of IEEE Std 269-2001. The STMR shall be calculated using equation
[A3] of Annex A.
6.3.1 Headset Send Noise
6.3.1.2 Measurement Method
Current:
With the headset mounted as specified by IEEE 269 (200x) and the receiver coupled to the
appropriate ear simulator in a quiet environment (ambient noise less than 30 dBA), free of
mechanical disturbances, measure the noise level at the digital interface output or the reference
codec decoder output with apparatus that includes A weighting.
Replacement:
Place the headset on HATS with the receiver coupled to the appropriate ear simulator in a quiet
environment (ambient noise less than 30 dBA). Measure the A-weighted noise level at the digital
interface output or the reference codec decoder output in accordance with the methods described
in Clause 8.5.2 of IEEE Std 269-2001.
6.3.2 Headset Send Single Frequency Interference
6.3.2.2 Measurement Method
Current:
With the headset mounted as specified by IEEE 269 (200x) and the receiver coupled to the
appropriate ear simulator in a quiet environment (ambient noise less than 30 dBA), free of
mechanical disturbances, measure the A-weighted noise level at VSEND with a selective voltmeter
or spectrum analyzer with an effective bandwidth of not more than 31 Hz, over the frequency
range of 100 to 8000 Hz. If FFT analysis is used, then “Flat Top” windowing shall be employed.
Replacement:
Place the headset on HATS with the receiver coupled to the appropriate ear simulator in a quiet
environment (ambient noise less than 30 dBA). Measure the A-weighted noise level at the digital
interface output or the reference codec decoder output in accordance with the methods described
in Clause 8.5.3 of IEEE Std 269-2001.
6.3.3 Headset Receive Noise
6.3.3.2 Measurement Method
Current:
The headset is mounted as specified by IEEE 269 (200x) and the receiver is coupled to the
appropriate ear simulator. A signal corresponding to a decoder quiet code is applied at the digital
interface. The A-weighted noise level is measured in the ear simulator. The ambient noise for this
measurement shall not exceed 30 dBA.
Replacement:
Place the headset on HATS with the receiver coupled to the appropriate ear simulator. A signal
corresponding to a decoder quiet code is applied at the digital interface. The A-weighted noise
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level is measured in accordance with the methods described in Clause 8.4.2 of IEEE Std 2692001. The ambient noise for this measurement shall not exceed 30 dBA.
6.3.4 Headset Receive Single Frequency Interference
6.3.4.2 Measurement Method
Current:
The headset is mounted as specified by IEEE 269 (200x) and the receiver is coupled to the
appropriate ear simulator. A signal corresponding to a decoder quiet code is applied at the digital
interface. The A-weighted noise level is measured in the ear simulator with a selective voltmeter
or spectrum analyzer, with an effective bandwidth of not more then 31 Hz, over the frequency
range of 100 to 8000 Hz. If FFT analysis is used, then “Flat Top” windowing shall be employed.
The ambient noise for this measurement shall not exceed 30 dBA.
Replacement:
Place the headset on HATS with the receiver coupled to the appropriate ear simulator. A signal
corresponding to a decoder quiet code is applied at the digital interface. The A-weighted noise
level is measured in accordance with the methods described in Clause 8.4.3 of IEEE Std 2692001. The ambient noise for this measurement shall not exceed 30 dBA.
6.4.1 Headset Send Distortion and Noise
6.4.1.1 Method of Measurement
Current:
The distortion and noise is measured according to IEEE 1329, 9.3.6. Apply a sinewave signal at
the MRP, with the levels given in Table 3 and the following frequencies: 315, 502, 803 and 1004
Hz. The ratio of the signal-to-total distortion and noise power of the digitally encoded signal
output is measured. The test frequency tolerance is 3%, but even submultiples of the sampling
frequency must not be used.
Replacement:
Place the headset on HATS with the receiver coupled to the appropriate ear simulator. The
distortion and noise is measured in accordance with the methods described in Clause 8.5.5 and
Annex H.4 of IEEE Std 269-2001. Apply a sinewave signal at the MRP, with the levels given in
Table 3 and the following frequencies: 160, 315, 502, 803, 1004, 2008, and 3150 Hz. The test
frequency tolerance is 3%, but even submultiples of the sampling frequency must not be used.
6.4.2 Headset Receive Distortion and Noise
6.4.2.1 Method of Measurement
Current:
The headset is mounted as specified by IEEE 269 (200x) and the receiver is coupled to the
appropriate ear simulator. The distortion and noise is measured according to IEEE 1329, 9.4.6.
Apply a digitally simulated sinewave, with the levels given in Table 4 and the following
frequencies: 315, 502, 803 and 1004 Hz. The ratio of signal-to-total distortion and noise power is
measured in the ear simulator. The test frequency tolerance is 3%, but even submultiples of the
sampling frequency must not be used.
Replacement:
Place the headset on HATS with the receiver coupled to the appropriate ear simulator. The
distortion and noise is measured in accordance with the methods described in Clause 8.4.5 and
Annex H.4 of IEEE Std 269-2001. Apply a digitally simulated sinewave, with the levels given in
Table 4 and the following frequencies: 160, 315, 502, 803, 1004, 2008, and 3150 Hz. The test
frequency tolerance is 3%, but even submultiples of the sampling frequency must not be used.
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6.5 Weighted Terminal Coupling Loss (TCLw)
6.5.1 Measurement Method
Current:
The attenuation from digital input to digital output is measured at 1/12 octave frequencies as
given by the R.40-series of preferred numbers in ISO 3 for frequencies from 290 to 8000 Hz,
using the measurement arrangement shown in Figure 12. See Annex C.
Replacement:
The attenuation from digital input to digital output is measured in accordance with the methods
described in Clause 8.8 of IEEE Std 269-2001. Testing is conducted at 1/12 octave frequencies as
given by the R.40-series of preferred numbers in ISO 3 for frequencies from 290 to 8000 Hz,
using the measurement arrangement shown in Figure 12. See Annex C.
Glenn R. Hess
MWM Acoustics
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