TIA-5050-2018 Volume Control Test System
Active Speech Level: The active level of speech or speech-like
signals using a speech voltmeter as defined in ITU-T P.56, method B. Measures the active speech level
by accounting for pauses that are a natural part of a speech signal.
Call Box:
The Call Box is the radio simulator used to establish the call with
the Device Under Test
(DUT). Call Box is synonymous with network system simulator, base
station simulator,
and radio communications equipment. Conversational Gain: The acoustic gain relative to the reference
acoustic level for a face-to-face conversation when listening with one ear. The acoustic level of
speech for a conversation at a distance of 1m meter is 64 dBSPL for binaural
listening. However, for monaural listening (such as when using a handset) the reference
acoustic level is 70dBSPL. (When only one ear is used for listening, a talker is
perceived to be about 6 dB quieter than when both ears are used. Therefore, to be perceived at
an equivalent loudness, the level at a single (monaural) ear should be about 6 dB
louder.)
Monoaural Conversational Gain = (Measured dBSPL Level – 70 dBSPL)
dB
dBm0: Power level in dBm, relative to a reference point called the zero
transmission level point (TLP), or 0 TLP. A signal level of X dBm at the 0 TLP is designated
X dBm0. In a
codec, the 0 TLP is specified in relationship to the full-scale
digital level or saturation.
However, digital saturation is generally not 0 dBm0. For μ-law
codecs 0 dBm0 is 3.17
dB below digital full scale. For A-law codecs 0 dBm0 is 3.14 dB
below digital full scale.
Device Under Test (DUT): The wireless (mobile) handset is referred
to as the DUT. DUT is
synonymous with User Equipment (UE), Mobile Equipment (ME), and
Mobile Station
(MS) used in other industry standards. Drum Reference Point (DRP):
A point located at the end of the ear canal, corresponding to the eardrum position. Also the point at which the ear simulator used
with a head and torso simulator (HATS) measures the sound pressure.Listener Reference Point (LRP):
A generic term representing the location at which the acoustic
output from the receiver is to be determined or specified. This may
be the Free Field or
Diffuse Field.
Diffuse Field (DF): Sound field in which the time average of the
mean-square sound
pressure is the same everywhere and the flow of acoustic energy
in all directions is equally probable.
Free Field (FF):
Sound field in a homogenous, isotropic medium free from
boundaries. In practice, the effects of boundaries on a free field
are negligible over the region of interest.
Receive Electrical Test Point (RETP): The point in the device test
arrangement which signals are applied to the DUT in the receive direction.
Sound Pressure Level: Sound pressure level is a value expressed as
a ratio of the pressure of a sound to a reference pressure. The following sound level units are used in
this standard:
dBPa:
The sound pressure level, in decibels, of a sound is 20 times the
logarithm to
the base 10 of the ratio of the pressure of this sound to the
reference pressure
of 1 Pascal (Pa).
NOTE: 1 Pa = 1 N/m2.
dBSPL: The sound pressure level, in decibels, of a sound is 20
times the logarithm to
the base 10 of the ratio of the pressure of this sound to the
reference pressureof 2 X 10-5 N/m2.
Where: 0 dBSPL = 20 micro-Pascals and 0 dBPa= 94 dBSPL.
Quiet room: A room with background noise no greater than 40 dBA.
4 TESTING CONSIDERATIONS
4.1 ADJUSTABLE FREQUENCY RESPONSE
If the terminal provides the ability to adjust the receive
frequency response (e.g., via a “tone control” feature), the terminal is considered to be compliant with this
Standard if it meets the requirements at one of the available frequency response settings.
4.2 ACOUSTIC TEST INTERFACE EQUIPMENT
An ITU-T P.58 compliant Head and Torso Simulator (HATS) equipped
with an ITU-T P.57 type 3.3 ear
simulator shall be used for the acoustic transmission measurements
specified in this standard. The ear
simulator calibration and usage, and the positioning of the handset
on the HATS shall be performed according to IEEE Std 269 unless stated otherwise in this document.
4.3 HANDSET POSITIONING AND MOUNTING FORCE
The handset shall be placed in either the standard test position as
specified in IEEE Std 269 or a recommended test position specified by the manufacturer that
complies with the recommended test
position requirements in IEEE Std 269.
Requirements in this standard include testing methods with a force
of 2 Newtons (2N) and 8N applied when placing the handset receiver against the artificial ear pinna
simulator for either the standard test position or recommended test position. The 2N force is used for
testing requirements related to use by persons with hearing devices and the 8N force is used for testing
requirements related to use by persons without hearing devices.
It is expected that for a person using a hearing device, the
hearing device provides the desired amplification. Therefore, the tests using a force of 2N against the
artificial ear pinna simulator ensure that when the telephone handset is used with a hearing device
operating in the acoustic (microphone) mode, the receiver acoustics will provide the expected acoustic
signals.
4.4 TEST SIGNAL AND ANALYSIS
The test signal specified for use in this document is the
uncompressed real male speech as published with IEEE Std 269.
The test signal Active Speech Level (ASL) for wireless (mobile)
device testing shall be -20 dBm0.
The analysis shall be done in 1/12 octave bands averaged over one
complete sequence of the four short sentences in the test signal unless otherwise specified.
The acoustic listener reference point shall be the Free Field (FF)
or the Diffuse Field (DF) as determined in the method of measurement.
4.5 NARROWBAND AND WIDEBAND TRANSMISSION MODES
The codecs to be used for testing in the Narrowband and Wideband
modes are stated below. If the required codec is not available on the DUT, then the codec closest
to the required codec may be used and the codec used shall be reported with the test results.
4.5.1 Narrowband mode testing
For testing of a terminal supporting narrowband telephony, the
system simulator shall use the AMR speech codec as defined in the 3GPP TS 26 series of specifications,
at the source coding bit-rate of 12.2 kbit/s.
4.5.2 Wideband mode testing
For testing of a terminal supporting wideband telephony, the system
simulator shall use the AMR-WB speech codec as defined in the 3GPP TS 26 series of specifications,
at the source coding bit rate of 12.65 kbit/s.
4.6 AIR INTERFACE
Wireless handsets typically provide multiple air interface modes
such as GSM, CDMA, WCDMA, LTE,
etc. When connecting a call between the audio test system and the
DUT through the Call Box, any available air interface that supports the codecs described above
may be used for testing.
4.7 PRECAUTIONS
Coding, decoding, packetization and other signal processing may
introduce significant delays that must be accounted for by the measurement system. Refer to IEEE Std 269
for additional precautions regarding test signal usage.
4.8 TEST ARRANGEMENT
The general test arrangement is shown in Figure 1. The Call Box
passes the voice channel stream to the
DUT without modification. There is no gain or loss in the voice
channel stream due to the Call Box
interface.
NOTES:
1. Additional information related to the air interface for the
various RF technologies is specified in
several 3GPP documents. A list of these can be found in 3GPP TS
26.132 V14.0.0 clause 4
2. Additional information related to the test setup can be found in
3GPP TS 26.132, V14.0.0 clause
5.1.
3. The RETP (receive electrical test point) is the point in the
device test arrangement where signals
are applied to the DUT in the receive direction.
ANSI/TIA-5050
7
5 TECHNICAL REQUIREMENTS
The following requirements shall be met for at least one volume
control setting for the narrowband
transmission mode (if supported) and the wideband transmission mode
(if supported).
5.1 RECEIVE VOLUME CONTROL PERFORMANCE
5.1.1 Requirement
1. With a mounting force of 8N, the DUT shall have at least one
volume control setting that will produce a conversational gain of ≥ 18 dB with the output distortion
and the frequency response meeting the requirements in clause 5.2.1 & 5.3.1 respectively.
2. With a mounting force of 2N, the DUT shall have at least one
volume control setting that will produce a conversational gain of ≥ 6 dB with the output distortion
and the frequency response meeting the requirements in clause 5.2.1 & 5.3.1 respectively.
NOTE:
Other acoustic receive features may be available such as additional
amplification, tone
control, automatic gain control, etc. ANSI/TIA-4953-B contains
performance requirements
for output levels and tone control operation for amplified devices.
5.1.2 Method of Measurement
1. Configure the DUT with a mounting force of 8N and test equipment
as shown in Figure 1 in an active call state with the applicable codec for the transmission
mode under test.
2. Set the DUT volume control to the maximum setting.
3. If the DUT has an adjustable tone control feature, a tone
control setting that meets the frequency response requirements in section 5.3.1 shall be used.
4. Apply the real speech test signal at a level of -20 dBm0 at the
RETP and measure the acoustic output at the Drum Reference Point (DRP) over one complete sequence of the
test signal.
5. Translate the measurement made at the DRP to the Free Field (FF)
using the translation data in
Annex B.
6. Over the applicable frequency band, determine the ASL in dBSPL
for the resulting sound pressure
level in accordance with Method B of ITU-T Recommendation P.56:
a. Narrowband 100 Hz through 4000 Hz.
b. Wideband 100 Hz through 7720 Hz.
7. Calculate the Conversational Gain by subtracting 70 dB from the
measured dBSPL.
[Conversational Gain = (Measured dBSPL Level – 70 dBSPL) dB]
8. Measure the output distortion per clause 5.2. If a distortion
failure occurs at the maximum volume control setting, reduce the volume control setting and repeat the
measurement to determine if a setting can be found for which the conversational gain requirement
is met without a distortion failure.
9. Repeat steps 2-8 with a mounting force of 2N.
