COMMUNICATIONS
/ SOCIALIST REPUBLIC OF VIETNAM
Independence - Freedom - Happiness
No.: 26/2015/ TT-BTTTT / Hanoi, date Sept 28, 2015
1037 + 1038/Date Oct 9, 2015
CIRCULAR
Promulgating “National technical regulation on cordless audio devices
in the range between 25 MHz and 2000 MHz”
Pursuant to Law on Technical Standard and Regulation dated June 29, 2006
Pursuant to Law on Telecommunication dated November 23, 2009;
Pursuant to Decree No.: 127/2007/ND-CP dated August 1, 2007 of the Government regulating in details and instructing to execute some articles of Law on Technical Standard and Regulation;
Pursuant to Decree No. 132/2013/ND-CP dated October 16, 2013 of the Government regulating functions, missions, rights and organization structure of Ministry of Information and communications;
Pursuant to proposal of Director General of Department of Science and Technology,
Minister of Information and communications promulgates Circular regulating National technical regulation on National technical regulation on cordless audio devices in the range between 25 MHz and 2000 MHz
Article 1. Promulgate along with this Circular the National technical regulation on cordless audio devices in the range between 25 MHz and 2000 MHz (QCVN 91:2015/BTTTT).
Article 2. This Circular is effective from April 1, 2016.
Article 3. Chief of Office, Director General of Department of Science and Technology, Heads of agencies, units of Ministry of Information and communications, Director of Department of Information and communications of provinces, cities directly under the Central and relevant organizations, individuals are responsible for executing this Circular./.
Recipients:- Ministries, ministerial agencies, agencies of the Government;
- People’s Committee and Department of Information and communications of the provinces, cities directly under the Central;
- Department of Document Inspection (Ministry of Justice);
- Announcement, Government Electronic Information Port;
- Ministry of Information and communications: Ministers and Vice Ministers;
Agencies, units of the Minister;
Ministerial Electronic Information Port;
- Filing: Document, Science and Technology. / MINISTER
(Signed)
Nguyen Bac Son
QCVN 91:2015/BTTTT
National technical regulation on cordless audio devices in the range between 25 MHz and 2000 MHz
Introduction
QCVN 91:2015/BTTTT is built on basis of ETSI ETSI EN 301 357-1 V1.4.1 (2008-11) of European Telecommunications Standards Institute (ETSI).
QCVN 91/2015/BTTTT is composed by Research Institute of Posts and Telecommunications, evaluated and approved by Department of Science and Technology, promulgated by Ministry of Information and communicationss with Circular No. 26/2015/TT-BTTTT date Sept 28, 2015.
National technical regulation on cordless audio devices in the range between 25 MHz and 2000 MHz
1. GENERAL REGULATION.
1.1. Governing scope
This regulation is applied to cordless audio devices in the range between 25 MHz and 2000 MHz as follows:
- Cordless headphones;
- Cordless speakers;
- In-ear monitoring devices using analog modulation with 300 kHz bandwidth or FDMA digital modulation with 300 kHz, 600 kHz, 1 200 kHz bandwidth;
- Cordless audio devices in car;
- Personal cordless devices;
- Equipment in broadband multi-channel audio system;
- Band II low-power devices with frequency between 87,5 MHz and 108 MHz (band II for broadcasting service) use analog modulation with bandwidth not over 200 kHz.
1.2. Applicable entities
This regulation is applied to organizations individuals in Vietnam and foreign country with production, business operation of equipment in scope of adjustment of this Regulation in territory of Vietnam.
1.3. References
ITU-R Recommendation BS.559-2 (1990): “Objective measurement of radio- frequency protection ratios in LF, MF and HF broadcasting".
IEC 60244-13 (1991): “Methods of measurement for radio transmitters - Part 13: Performance characteristics for FM sound broadcasting".
ETSI TR 102 273 (all parts) (2001): “Electromagnetic compatibility and Radio spectrum Matters (ERM); Improvement on Radiated Methods of Measurement (using test site) and evaluation of the corresponding measurement uncertainties".
ANSI C63.5 (2006): “American National Standard for Calibration of antennas Used for Radiated Emission Measurements in Electro Magnetic noise".
IEC 60489-3 (1988): “Methods of measurement for radio equipment used in the mobile services. Part 3: Receivers for A3E or F3E emissions”.
1.4. Definition
1.4.1. Allocated or applicable band. Band is defined in accordance with planning of national radio frequency spectrum.
1.4.2. Artificial antenna
Load is adjusted on radiation, with nominal impedance equal to high-frequency impedance of equipment under test. This impedance is stipulated by equipment supplier.
1.4.3. Channel bandwidth
The maximum bandwidth including necessary bandwidth of transmitter.
1.4.4. Cordless
The connection between two or more entities without physical connection. This regulation only recommends cordless systems operating on radio frequency.
1.4.5. Integral antenna
The antenna is designed to be connected to equipment without using standard connector and is considered to be a part of equipment.
1.4.6. Integral antenna for Band II LPD only
Antenna is designed to be fixed to equipment and is considered to be an integral part of equipment.
1.4.7. Necessary bandwidth
Width of frequency band for each emission, adequate to ensure information transmission with speed and quality as required in predetermined conditions.
1.4.8. Nominal channel frequency
Channel frequency is announced by manufacturer
1.4.9. Occupied bandwidth
The width of the frequency band in which the average power emitted at lower frequencies of the lower than lower bounds and higher than upper bound of that frequency band equal to given percentage b/2 of the total average power of that emission.
Unless otherwise specified, selected value (b/2 is 0.5%.
1.4.10. Port
Any connection point above or in EUT used to connect cable to equipment or from that equipment.
1.4.11. Radiated measurements
Measurements relating to radiation field absolute value measurement.
1.4.12. Spurious emission
Emission on one or more frequencies beyond necessary bandwidth and this emission can be attenuated without affecting the corresponding transmission of information. Spurious emission includes harmonic emission, parasitic emission, inter-modulation product and frequency transition product, but not including emission beyond band.
1.4.13. Band II low power devices
Short-distance low-power FM transmitters operate in FM band for broadcasting service with frequency range between 87,5 MHz to108 MHz used to provide a radio connection line between a personal audio device, including mobile phone and entertainment in car or entertainment system in the house.
1.5. Symbol
l / WavelengthdBc / Decibel relative to carrier power levels
E / Field intensity
fc / Carrier frequency
fo / operating frequency
1.6. Abbreviations
ac / Alternating current / Alternating current
B / Channel bandwidth / Channel bandwidth
BN / Necessary bandwidth / Necessary bandwidth
CW / Continuous wave / Continuous wave
dc / Direct current / Direct current
e.r.p / Effective radiated power / Effective radiated power
e.i.r.p / Equivalent Isotropically Radiated Power / Equivalent Isotropically Radiated Power
EUT / Equipment Under Test / Equipment Under Test
FDMA / Frequency Division Multiple Access / Frequency Division Multiple Access
FM / Frequency Modulation / Frequency Modulation
HF / High Frequency / High Frequency
LF / Low Frequency / Low Frequency
LPD / Low Power Device / Low Power Device
OATS / Open Area Test Site / Open Area Test Site
RBW / Resolution BandWidth / Resolution BandWidth
RF / Radio Frequency / Radio Frequency
SINAD / (Signal + Noise + Distortion) over (Noise + Distortion) / (Signal + Noise + Distortion) over (Noise + Distortion)
SRD / Short Range Device / Short Range Device
Tx / Transmitter / Transmitter
VBW / Video BandWidth / Video BandWidth
VSWR / Voltage standing Wave Ratio / Voltage standing Wave Ratio
2. TECHNICAL REGULATIONS
2.1. General requirements
2.1.1. Requirements to equipment for measurement and test
EUT must satisfy adequate requirements of this regulation in all channels to be exploited.
The Party with EUT must have equipment test process.
The Party with EUT must specify the band which devices are allowed to operate.
The Party with EUT must provide full information relating to interface, any tool, test fixture box that allow to:
- Connect to a DC power;
- Connect analog audio;
- Limit transmitter deviation; and
- Establish input signal level and input sound level in normal operation mode in place of a frequency 500 Hz sinusoidal input signal (or 1 KHz to band II LPD equipment). Manufacturer must announce the establishment of other adjustment levels so that it will not invalidate the tests.
In case band II low-power equipment replaces integrated equipment, a data file of sinusoidal signals needs to be established to stimulate transmitter input. The amplitude of these signals can be changed (but with the same amplitude for each signal) to be able to accurately adjust the carrier frequency deviation of the transmitter output ± 75 kHz.
In addition to the technical documentation, the Party with EUT must also provide device operation manuals with similar content to the manual of the equipment samples.
To simplify and harmonize the test methods between manufacturers and test laboratories, the measurements must comply with this standard for all models of equipment specified in sections from 2.1.1.1 to 2.1.1.6.2.
2.1.1.1. Equipment under Test
The Party with EUT must supply sample of EUT.
EUT must be typical equipment in production model.
2.1.1.2. Definitions alignment range and preset channel frequency range
Alignment range is the frequency range in which receiver or transmitter can be programmed and/or re-aligned to operate with frequency mononuclear oscillator without any physical change on external circuit except the substitution of:
- Program ROM memories.
- Crystals.
- Frequency setting elements (in receiver and transmitter). These elements cannot be adjusted by users.
Preset channel frequency range is the maximum frequency range specified by the manufacturer, so receiver and transmitter can be operated without resetting the program or re-alignment.
When bringing the equipment to the conformance tests, the Party with EUT should inform the alignment range of receiver and transmitter. EUT parties must also provide preset channel frequency range of receiver and transmitter (two ranges may vary).
For band II low-power devices (LPD), frequency range of transmitter must be in the frequency range between 87.6 MHz and 107.9 MHz.
2.1.1.3. Alignment range
Alignment range of receiver and transmitter can be different, but must be in the specified frequency band.
2.1.1.4. Selection of test frequency
The frequencies to be tested shall be selected by the manufacturer, consistent with sections 2.1.1.5 to 2.1.1.7. When selecting the test frequency, the manufacturer must ensure that the frequency is selected in one or more bandwidth stipulated by the nation.
For band II low-power devices, the carrier frequency of the transmitter must be in the frequency range from 87.6 MHz to 107.9 MHz, select the frequency to create radiation output power.
2.1.1.4.1. Single-channel equipment test
Perform full test on a channel in B/2 center frequency of the alignment range (B is channel bandwidth).
2.1.1.4.2. Two-channel equipment test
The Party testing equipment must provide test samples, perform the tests on the 2 channels.
The frequency of the upper channel must be in the B/2 highest frequency of preset channel band. The frequency of the lower channel above must be in the B/2 lowest frequency of preset channel band. All tests must be performed on 2 channels.
2.1.1.4.3. Multi-channel equipment test (more than two channels)
The Party testing equipment must provide test samples, perform the tests on the 3 channels. The center frequency of the preset channel band of test equipment sample must correspond to the center frequency of the alignment range.
Fully implement the tests at frequency in B/2 center frequency, the highest frequency and the lowest frequency of preset channel band range.
2.1.1.5. Measurement and test of equipment with external frequency control
The Party testing equipment must provide test samples, perform the tests on the 3 channels. This EUT sample facilitates the control of external frequency.
Measurements below must be implemented in two inverters of alignment range of devices:
- Section 2.2.3: Frequency error;
- Section 2.2.4: Carrier power;
- Section 2.2.5: Channel bandwidth
Measurements below must be implemented in frequency between alignment ranges of devices:
- Section 2.2.6: Spurious emissions;
- Section 2.2.7: Cordless audio transmitter shut off lock.
2.1.1.6. Equipment test with integrated antenna
For the convenience of the relevant measurements, use test fixture box described in Section 2.1.3.2, or equipment with RF port fixed or temporarily mounted/external port.
This section does not apply for band II low-power device.
2.1.1.6.1. Equipment has a RF portal fixed inside
The Party with EUT will demonstrate how to use RF port fixed inside the device with its diagram. Write these conditions in measurement and test report.
2.1.1.6.2. Equipment has a RF portal fixed temporarily
The Party with EUT must provide two EUT samples for test laboratory, a sample connected to RF 50 connector W fixed temporarily with removed antenna and a sample with connected antenna. Each sample of device under test is used for the appropriate measurements.
Party with EUT must provide device with RF port temporarily attached together with its scheme. The use of temporarily mounted RF ports enables easy measurement, which must also be stated in the test report. The supplementation of a temporarily mounted RF port does not affect the performance of the EUT.
2.1.2. Condition of test, power and environment temperature
2.1.2.1. Condition of measurement and test
Measurements must be implemented under normal test conditions unless otherwise required in limited condition.
Measurement conditions and measurement methods must be stipulated in section 2.1.2.2 to 2.1.2.3.2.3
2.1.2.2. Power of measurement and test
In conformance measurements, the power of the equipment under test must be replaced by a test power capable of providing the test voltages as described in Section 2.1.2.3.2. Internal impedance of the power under test must be small enough so that it will not affect the measurement results Test voltage shall be measured at the input of the equipment under test.
For devices powered by battery, the battery shall be removed from the device under test and the test power must be connected to the contact point between the device with and batteries. When performing radiation measurements,arrange the external power lines so as not to affect the measurement. If you need to replace external power supply with Internal battery of device with specified voltage, record in the test report.