ETSI I-ETS 300 422 ed.1 (1995-12)
Radio Equipment and Systems (RES); Technical characteristics and test methods for wireless microphones in the 25 MHz to 3 GHz frequency range
Radio Equipment and Systems (RES); Technical characteristics and test methods for wireless microphones in the 25 MHz to 3 GHz frequency range
DI/RES-08-0301
Radijska oprema in sistemi (RES) - Tehnične karakteristike in preskušalne metode za brezžične mikrofone v frekvenčnem območju od 25 MHz do 3 GHz
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-1999
5DGLMVNDRSUHPDLQVLVWHPL5(67HKQLþQHNDUDNWHULVWLNHLQSUHVNXãDOQHPHWRGH
]DEUH]åLþQHPLNURIRQHYIUHNYHQþQHPREPRþMXRG0+]GR*+]
Radio Equipment and Systems (RES); Technical characteristics and test methods for
wireless microphones in the 25 MHz to 3 GHz frequency range
Ta slovenski standard je istoveten z: I-ETS 300 422 Edition 1
ICS:
33.060.99 Druga oprema za radijske Other equipment for
komunikacije radiocommunications
33.100.01 Elektromagnetna združljivost Electromagnetic compatibility
na splošno in general
33.160.50 Pribor Accessories
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERIM
EUROPEAN I-ETS 300 422
TELECOMMUNICATION December 1995
STANDARD
Source: ETSI TC-RES Reference: DI/RES-08-0301
ICS: 33.020, 33.060.20
radio, radio mic,testing
Key words:
Radio Equipment and Systems (RES);
Technical characteristics and test methods for wireless
microphones in the 25 MHz to 3 GHz frequency range
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - secretariat@etsi.fr
X.400: Internet:
Tel.: +33 92 94 42 00 - Fax: +33 93 65 47 16
*
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1995. All rights reserved.
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I-ETS 300 422: December 1995
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.
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I-ETS 300 422: December 1995
Contents
Foreword .7
Introduction.7
1 Scope .9
2 Normative references.10
3 Definitions, abbreviations and symbols.10
3.1 Definitions .10
3.2 Abbreviations .10
3.3 Symbols .11
4 Functional characteristics.11
4.1 Radio microphone descriptions .11
5 General.12
5.1 Presentation of equipment for testing purposes .12
5.1.1 Choice of model for type testing.12
5.1.2 Definitions of alignment and switching ranges .13
5.1.3 Definition of the categories of the Alignment Range (AR1 and AR2).13
5.1.4 Choice of frequencies.13
5.1.5 Testing of single channel equipment of category AR1.13
5.1.6 Testing of single channel equipment of category AR2.13
5.1.7 Testing of two channel equipment of category AR1.14
5.1.8 Testing of two channel equipment of category AR2.14
5.1.9 Testing of multi-channel equipment (more than two channels) of category
AR1 .14
5.1.10 Testing of multi-channel equipment (more than two channels) of category
AR2 (switching range less than alignment range).14
5.1.11 Testing of multi-channel equipment (more than two channels) of category
AR2 (switching range equals the alignment range).15
5.1.12 Testing of equipment without a permanent external RF port .15
5.1.12.1 Equipment with a permanent internal RF port .15
5.1.12.2 Equipment with a temporary RF port.15
5.2 Mechanical and electrical design.15
5.2.1 General.15
5.2.2 Limiting threshold .15
5.2.3 Controls .16
5.2.4 Integral antenna .16
5.2.5 Marking (equipment identification) .16
5.3 Interpretation of the measurement results.17
6 Test conditions, power sources and ambient conditions.17
6.1 Normal and extreme test-conditions.17
6.2 Test power source .17
6.3 Normal test conditions .17
6.3.1 Normal temperature and humidity.17
6.3.2 Normal test power source voltage.18
6.3.2.1 Mains voltage.18
6.3.2.2 Nickel-cadmium cells.18
6.3.2.3 Other power sources .18
6.4 Extreme test conditions .18
6.4.1 Extreme temperatures.18
6.4.1.1 Procedures for tests at extreme temperatures.18
6.4.2 Extreme test power source voltages .18
6.4.2.1 Mains voltage.18
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I-ETS 300 422: December 1995
6.4.2.2 Re-chargeable battery power sources . 18
6.4.2.3 Power sources using other types of batteries . 19
6.4.2.4 Other power sources. 19
7 General conditions. 19
7.1 Normal test modulation . 19
7.2 Artificial antenna. 20
7.3 Test fixture . 21
7.4 Test site and general arrangements for radiated measurements . 21
7.5 Modes of operation of the transmitter . 21
7.6 Arrangement for test signals at the input of the transmitter . 21
8 Methods of measurement and limits for transmitter parameters. 21
8.1 Frequency error. 22
8.1.1 Definition. 22
8.1.2 Method of measurement. 22
8.1.3 Limit . 22
8.2 Carrier power. 22
8.2.1 Definition. 22
8.2.2 Method of measurement for equipment without integral antenna . 22
8.2.3 Method of measurement for equipment with integral antenna . 23
8.2.3.1 Method of measurement under normal test conditions. 23
8.2.3.2 Method of measurement under extreme test conditions. 23
8.2.4 Limit . 23
8.3 Channel bandwidth. 24
8.3.1 Definition. 24
8.3.2 Measurement of Necessary Bandwidth (BN). 24
8.3.3 Limits . 25
8.4 Spurious emissions . 25
8.4.1 Definitions . 25
8.4.2 Method of measuring the effective radiated power. 25
8.4.3 Limits . 26
8.4.4 Measuring receiver . 26
8.5 Transient frequency behaviour of the transmitter. 26
8.5.1 Definitions . 26
8.5.2 Method of measurement. 27
8.5.3 Method of measurement (frequency changing). 28
8.5.4 Limits . 28
9 Receiver. 28
9.1 Spurious emissions . 28
9.1.1 Definitions . 28
9.1.2 Method of measuring the power level in a specified load. 29
9.1.3 Method of measuring the effective radiated power of the enclosure. 29
9.1.4 Method of measuring the effective radiated power. 30
9.1.5 Limits . 30
10 Measurement uncertainty . 30
Annex A (normative): Radiated measurement . 31
A.1 Test sites and general arrangements for measurements involving the use of radiated fields . 31
A.1.1 Outdoor test site. 31
A.1.1.1 Test support for body worn equipment . 31
A.1.1.2 Standard position. 32
A.1.2 Test antenna . 32
A.1.3 Substitution antenna. 32
A.1.4 Optional additional indoor site . 33
A.2 Guidance on the use of radiation test sites . 34
A.2.1 Measuring distance . 34
A.2.2 Test antenna . 34
A.2.3 Substitution antenna. 34
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I-ETS 300 422: December 1995
A.2.4 Artificial antenna .34
A.2.5 Auxiliary cables .34
A.3 Further optional alternative indoor test site using an anechoic chamber .35
A.3.1 Example of the construction of a shielded anechoic chamber .35
A.3.2 Influence of parasitic reflections in anechoic chambers .35
A.3.3 Calibration of the shielded anechoic chamber.36
Annex B (normative): Measurement of Necessary Bandwidth (BN) .38
Annex C (informative): Graphic representation of the selection of equipment and frequencies for
testing of single and multi-frequency equipment .39
Annex D (informative): Bibliography.41
History.42
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I-ETS 300 422: December 1995
Foreword
This Interim European Telecommunication Standard (I-ETS) has been produced by the Radio Equipment
and Systems (RES) Technical Committee of the European Telecommunications Standards Institute
(ETSI).
Every I-ETS prepared by ETSI is a voluntary standard. This I-ETS may contain text concerning
conformance testing of the equipment to which it relates. This text should be considered as guidance only
and does not make this I-ETS mandatory.
Annex A provides normative specifications concerning radiated measurements.
Annex B describes the test set-up for the measurement of Necessary Bandwidth (BN).
Annex C provides a graphic representation of the equipment and frequencies for the testing of single and
multi-frequency equipment.
Annex D provides a Bibliography.
Proposed announcement date
Date of adoption of this I-ETS: 27 October 1995
Date of latest announcement of this I-ETS (doa): 31 March 1996
Introduction
This I-ETS is based on the CEPT Recommendation T/R 20-06 [1].
This CEPT Recommendation has been a frame that led to many national prescriptions that differed,
sometimes substantially, between European countries. The rapidly increasing quantities of wireless
microphones (hereafter referred to as radio microphones) in operation, both legal and illegal, together with
the greater mobility of the users, either professional or private, has led to a serious situation with many
occurrences of interference and irregular operation. Legal radio microphones, being fundamentally low
power devices, are interfered with more than the generators of the interference, and suffer primarily from
this situation.
In preparing this I-ETS, much attention has been given to assure a low interference probability, while at
the same time allowing a maximum flexibility and service to the end-user.
This I-ETS provides the necessary parameters for equipment to obtain common approval throughout
Europe. It also is intended to make it easier for the frequency management authorities to find harmonized
frequency allocations. Common technical specifications and harmonized frequency allocations are
expected to reduce greatly the present problems of interference and illegal use.
This I-ETS is a type testing standard based on spectrum utilisation parameters and does not include
performance characteristics that may be required by the user or requirements for interfacing equipment.
This I-ETS is intended to specify the minimum performance and the methods of measurement of Wireless
Microphones as specified in the scope.
Type test measurements should be performed in one of the accredited test laboratories, accepted by the
various national regulatory authorities in order to grant type approval, provided the national regulatory
requirements are met. This is in compliance with CEPT Recommendation T/R 71-03 [2].
In addition, national administrations may accept a "certificate of conformity" based on a type test report. If
equipment available on the market is required to be checked, it should be tested in accordance with the
methods of measurement specified in this I-ETS.
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I-ETS 300 422: December 1995
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I-ETS 300 422: December 1995
1 Scope
This I-ETS covers the minimum characteristics considered necessary in order to make the best use of the
available frequencies. It does not necessarily include all the characteristics that may be required by a user,
nor does it necessarily represent the optimum performance achievable.
This I-ETS applies to equipment with modulation systems operating on radio frequencies between 25 MHz
and 3 GHz. Although analogue Frequency Modulation (FM) is at present used for the majority of wireless
microphones, this specification does not preclude any other constant carrier modulation technique, e.g.
Gaussian Filtered Minimum Shift Keying (GMSK) or Generalized Tamed Frequency Modulation (GTFM),
provided that the modulation spectrum lies within a standardized spectral mask.
This I-ETS does not apply to wireless microphones employing Time Division Multiple Access (TDMA),
frequency hopping and spread spectrum or similar forms of modulation.
EMC requirements are covered by draft prETS 300 445.
Additional standards or specifications may be required for equipment intended to interface to the Public
Switched Telephone Network (PSTN). This facility may be submitted to regulatory conditions.
This I-ETS may be used by accredited test laboratories for type testing of the equipment. The
performance of the equipment submitted for type testing should be representative of the performance of
the corresponding production models.
This I-ETS contains instructions for the presentation of equipment for type testing purposes.
Power limits recommended in this I-ETS have been chosen to allow maximum simultaneous reusage of
frequency allocations. National regulations on power output may apply up to the limits quoted below.
NOTE: If higher power limits are required reference should be made to I-ETS 300 454 Wide
band audio links, which is currently under preparation.
Equipment effective radiated power (erp)
or conducted
Class 1 Class 2
Radio microphones 50 mW 2 mW
Tour guide systems 10 mW 2 mW
10 mW 2 mW
Aids for the handicapped
The types of equipment covered by this I-ETS are as follows:
- professional hand held radio microphones;
- professional body worn radio microphones;
- consumer radio microphones;
- tour guide systems;
- aids for the handicapped.
The classes of equipment given in this I-ETS are as follows:
- class 1 equipment would normally be considered as a category requiring an operator licence;
- class 2 equipment would be considered in some countries as not requiring an operator licence.
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I-ETS 300 422: December 1995
2 Normative references
This I-ETS incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this I-ETS only when incorporated in it by amendment or revision. For undated references the
latest edition or the publication referred to applies.
[1] CEPT Recommendation T/R 20-06 (1977): "Transmitters and receivers for low
power cordless microphone systems".
[2] CEPT Recommendation T/R 71-03: "Procedures for type testing and approval
for radio equipment intended for non-public systems".
[3] ITU-R Recommendation 559-2: "Objective measurement of radio-frequency
protection ratios in LF, MF and HF broadcasting".
[4] IEC 244: "Methods of measurement for radio transmitters".
[5] ETR 028: "Radio Equipment and Systems (RES); Uncertainties in the
measurement of mobile radio equipment characteristics".
3 Definitions, abbreviations and symbols
3.1 Definitions
For the purposes of this I-ETS, the following definitions apply:
conducted measurements: Measurements that are made using a direct 50 Ω connection to the EUT.
integral antenna: An antenna, with or without a connector, designed as, and declared as by the
manufacturer, an indispensable part of the equipment.
integral microphone: A microphone, designed as, and declared as by the manufacturer, an
indispensable fixed part of the equipment.
limiter threshold: The audio input or output level at which the transmitter audio limiter action may be said
to commence. It is specified with any accessible variable gain controls set according to the manufacturer's
instructions, with a sinusoidal input signal of 500 Hz.
radiated measurements: Measurements that involve the absolute measurement of a radiated
electro-magnetic field.
carrier grid: Evenly spaced raster in a given frequency band for the allocation of carrier frequencies. The
minimum distance of two carriers in use is a multiple of the raster dependent on type and usage of the
equipment.
channel bandwidth: A frequency band of defined width (as a multiple of the carrier grid) including safety
margin for operation on adjacent channels, located symmetrically around carrier frequency in the carrier
grid.
port: Any connection point on or within the Equipment Under Test (EUT) intended for the connection of
cables to or from that equipment.
Radio Frequency (RF) port: Any connection point on or within the EUT intended for the connection of RF
cables. RF ports are treated as 50 Ω connection points unless otherwise specified by the manufacturer.
3.2 Abbreviations
For the purposes of this I-ETS, the following abbreviations apply:
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I-ETS 300 422: December 1995
ac alternating current
AR1 Alignment Range 1
AR2 Alignment Range 2
B declared channel Bandwidth (see table 1)
BN Necessary Bandwidth
dc direct current
erp effective radiated power
EUT Equipment Under Test
GMSK Gaussian Filtered Minimum Shift Keying
GTFM Generalized Tamed Frequency Modulation
LF Low Frequency
PSTN Public Switched Telephone Network
RBW Resolution BandWidth
RF Radio Frequency
Rx Receiver
SINAD Signal to Noise and Distortion ratio
TDMA Time Division Multiple Access
Tx Transmitter
VBW Video BandWidth
3.3 Symbols
For the purposes of this I-ETS, the following symbols apply:
λ wavelength in metres
μF microFarad
μW microWatt
dBc dB relative to the carrier level
dBm dB relative to 1 mW
E field strength
Eo reference field strength, (see annex A)
fc carrier frequency
fo operating frequency
GHz gigaHertz
H Henry
kHz kiloHertz
lim limiting
MHz megaHertz
mW milliWatt
nW nanoWatt
R distance, (see annex A)
Ro reference distance, (see annex A)
4 Functional characteristics
4.1 Radio microphone descriptions
Radio microphones normally use wide band frequency modulation to achieve the necessary audio
performance for professional use. For the majority of applications the modulated transmitter signal
requires a channel bandwidth of 200 kHz.
The radio part of the transmitter and receiver shall be made up exclusively from equipment that has been
approved according to this I-ETS.
Other equipment that may be connected to radio microphones shall fulfil the standards applicable to that
equipment (if any).
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I-ETS 300 422: December 1995
5 General
5.1 Presentation of equipment for testing purposes
Each equipment submitted for type testing shall fulfil the requirements of this I-ETS on all channels over
which it is intended to operate.
The applicant shall complete the appropriate application form when submitting equipment for type testing.
For radio microphones which may use a variety of audio capsules the manufacturer shall supply the test
sample with an audio test fixture, to substitute the audio capsule, with suitable input and output
impedance.
The applicant shall state the channel bandwidth(s) within which the equipment is designed to operate
chosen from table 1.
Table 1: Channel bandwidth (channel allocation within a 25 kHz carrier grid)
Declared channel Bandwidth (B) Designation
50 kHz L
75 kHz M
100 kHz P
150 kHz Q
200 kHz R
The applicant shall state the audio input limiting threshold, (see subclause 5.2.2).
The applicant shall also supply all relevant interface information to allow:
- direct current (dc) power connection;
- RF connection;
- audio connection;
- the limiting of the transmitter; and
- the setting of any input audio level controls for normal operation, for a sinusoidal input signal of
500 Hz. The manufacturer shall specify the settings of any other controls necessary to avoid
invalidating the test measurements.
Besides the technical documentation, the applicant should also supply an operating manual for the
device(s).
To simplify and harmonize the type testing procedures between the different test laboratories,
measurement shall be performed, according to this I-ETS, on samples of equipment defined in
subclauses 5.1.1 to 5.1.12.2.
These subclauses are intended to give confidence that the requirements set out in this I-ETS have been
met without the necessity of performing measurements on all channels.
5.1.1 Choice of model for type testing
The applicant shall provide one or more production model(s) of the equipment, including all antenna(s)
designed for the equipment, and that are required to be covered by the type testing.
If type approval is given on the basis of tests on a preliminary model, the corresponding production
models shall be identical in all respects with the preliminary model tested.
In the case of radio microphone equipment without a permanent external RF port, see subclause 5.1.12.
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I-ETS 300 422: December 1995
5.1.2 Definitions of alignment and switching ranges
The alignment range is defined as the frequency range over which the receiver and the transmitter can be
programmed and/or re-aligned to operate with a single oscillator frequency multiplication, without any
physical change of components other than:
- programmable read only memories supplied by the manufacturer or the manufacturer's nominee;
- crystals;
- frequency setting elements (for the receiver and transmitter). These elements shall not be
accessible to the end user and shall be declared by the applicant in the application form.
The switching range is the maximum frequency range over which the receiver or the transmitter can be
operated without re-programming or realignment.
The applicant shall, when submitting equipment for test, state the alignment ranges for the receiver and
transmitter. The applicant shall also state the switching range of the receiver and the transmitter (which
may differ).
5.1.3 Definition of the categories of the Alignment Range (AR1 and AR2)
The alignment range for the receiver and transmitter, which may be different, falls into one of two
categories (see annex C for a graphical representation).
AR1: this corresponds to a limit of less than or equal to 10 % of the highest frequency of the alignment
range, which is equal to or less than 500 MHz, or less than or equal to 5 % where the highest
alignment frequency is above 500 MHz;
AR2: this corresponds to a limit of greater than 10 % of the highest frequency of the alignment range,
which is equal to or less than 500 MHz, or greater than 5 % where the highest alignment frequency
is above 500 MHz.
5.1.4 Choice of frequencies
The frequencies for testing shall be chosen by the applicant, in accordance with subclauses 5.1.5 to
5.1.11.
5.1.5 Testing of single channel equipment of category AR1
Full tests shall be carried out on a channel within 100 kHz of the centre frequency of the alignment range
on one sample of the equipment.
5.1.6 Testing of single channel equipment of category AR2
Three samples shall be tested. Tests shall be carried out on a total set of three channels as follows:
- sample one shall be within 100 kHz of the highest frequency of the alignment range;
- sample two shall be within 100 kHz of the lowest frequency of the alignment range;
- sample three shall be within 100 kHz of the centre frequency of the alignment range.
Full tests shall be carried out on all three channels.
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I-ETS 300 422: December 1995
5.1.7 Testing of two channel equipment of category AR1
One sample shall be submitted to enable tests to be carried out on both channels.
The frequency of the upper channel shall be within 100 kHz of the highest frequency of the switching
range. The frequency of the lower channel shall be within 100 kHz of the lowest frequency of the switching
range. In addition, the average of the frequencies of the two channels shall be within 100 kHz of the centre
frequency of the alignment range.
Full tests shall be carried out on both channels.
5.1.8 Testing of two channel equipment of category AR2
Three samples of the equipment shall be tested. Tests shall be carried out on a total of four channels.
The highest frequency of the switching range of one sample shall be within 100 kHz of the centre
frequency of the alignment range. The frequency of the upper channel shall be within 100 kHz of the
highest frequency of the switching range and the frequency of the lower channel shall be within 100 kHz of
the lowest frequency of the switching range.
Full tests shall be carried out on both channels.
The frequency of one of the channels of the second sample shall be within 100 kHz of the highest
frequency of the alignment range.
Full tests shall be carried out on this channel.
The frequency of one of the channels of the third sample shall be within 100 kHz of the lowest frequency
of the alignment range.
Full tests shall be carried out on this channel.
5.1.9 Testing of multi-channel equipment (more than two channels) of category AR1
One sample of the equipment shall be submitted to enable tests to be carried out on three channels. The
centre frequency of the switching range of the sample shall correspond to the centre frequency of the
alignment range.
Full tests shall be carried out on a frequency within 100 kHz of the centre, lowest and highest frequencies
of the switching range.
5.1.10 Testing of multi-channel equipment (more than two channels) of category AR2
(switching range less than alignment range)
Three samples of the equipment shall be tested. Tests shall be carried out on a total of five channels.
The centre frequency of the switching range of one sample shall be within 100 kHz of the centre frequency
of the alignment range. The frequency of the upper channel shall be within 100 kHz of the highest
frequency of the switching range and the frequency of the lower channel shall be within 100 kHz of the
lowest frequency of the switching range.
Full tests shall be carried out on the centre channel, spurious emission tests only on the upper and lower
channels.
The frequency of one of the channels of the second sample shall be within 100 kHz of the highest
frequency of the alignment range.
Full tests shall be carried out on this channel.
The frequency of one of the channels of the third sample shall be within 100 kHz of the lowest frequency
of the alignment range.
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I-ETS 300 422: December 1995
Full tests shall be carried out on this channel.
5.1.11 Testing of multi-channel equipment (more than two channels) of category AR2
(switching range equals the alignment range)
One sample shall be submitted to enable tests to be carried out on three channels.
The centre frequency of the switching range of the sample shall correspond to the centre frequency of the
alignment range.
Full tests shall be carried out on a frequency within 100 kHz of the centre frequency of the switching range
and within 100 kHz of the lowest and also within 100 kHz of the highest frequency of the switching range.
5.1.12 Testing of equipment without a permanent external RF port
To facilitate relative measurements, use may be made of a test fixture as described in subclause 7.3, or
the equipment may be supplied with a permanent internal or temporary internal/external RF port.
5.1.12.1 Equipment with a permanent internal RF port
The way to access a permanent internal RF port shall be stated by the applicant with the aid of a diagram.
The fact that use has been made of a permanent internal RF port shall be recorded in the test report.
5.1.12.2 Equipment with a temporary RF port
The applicant shall submit two sets of equipment to the test laboratory, one fitted with a temporary 50 Ω
RF connector with the antenna disconnected and the other with the antenna connected. Each equipment
shall be used for the appropriate tests.
The way the temporary RF port is implemented shall be stated by the applicant with the aid of a diagram.
The fact that use has been made of the temporary RF port to facilitate measurements shall be stated in
the test report. The addition of a temporary RF port should not influence the performance of the EUT.
5.2 Mechanical and electrical design
5.2.1 General
The equipment submitted by the applicant shall be designed, constructed and manufactured in
accordance with sound engineering practice, and with the aim of minimising harmful interference to other
equipment and services.
5.2.2 Limiting threshold
The limiting threshold is defined as the minimum audio input level at which the slope of the audio
input/output transfer curve, with the levels expressed in dB, is greater or equal to 4:1 (see figure 1). For
non-linear or companded systems, this point is determined with a complimentary audio decoding module
connected to the test demodulator. The measurement is made at 500 Hz with any user accessible gain
controls set according to the manufacturer's instructions.
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I-ETS 300 422: December 1995
dB
(Arbitrary reference)
_
+ 10
Audio output
_
level from
_
complimentary
- 10
Slope = 4:1
audio decoding
_
circuits
- 20
Slope = 1:1
_
- 30
|||
||
- 30 - 20 - 10 0 dB(lim) + 10
Audio input level to transmitter (dB relative to limiting threshold)
Figure 1: Determination of audio input limiting threshold
In the case of a transmitter designed for acoustical input only, with an integral microphone and no limiter,
a sound pressure of 128 dB relative to 20 μPa is regarded as the limiting threshold.
5.2.3 Controls
Those controls that, if maladjusted, might increase the interfering potentialities of the equipment shall only
be accessible by partial or complete disassembly of the device and requiring the use of tools.
5.2.4 Integral antenna
Type approval of equipment with integral antenna only applies to that equipment together with the antenna
originally provided by the manufacturer for type testing.
5.2.5 Marking (equipment identification)
The equipment shall be marked in a visible place. This marking shall be legible, tamper-proof and durable.
The marking shall include:
- the name of the manufacturer or his trade mark;
- the type designation of the manufacturer;
- serial number;
- operational frequency range;
- national and/or international type approval;
- modulation type.
Alternatively the marking shall consist of:
- a normally readable label; and
- the information detailed above, stored electronically in a secure format, which is easily readable by
either:
- the receiver provided by the manufacturer; or
- a reading system provided by the manufacturer with each transmitter.
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5.3 Interpretation of the measurement results
The interpretation of the results recorded in the appropriate test report for the measurements described in
this I-ETS shall be as follows:
- the measured value related to the corresponding limit shall be used to decide whether an
equipment meets the requirements of the I-ETS;
- the measurement uncertainty value for the measurement of each parameter shall be separately
included in the test report;
- the recorded value of the measurement uncertainty shall be, for each measurement, equal to or
lower than the figures in the table of measurement uncertainty as in clause 10.
6 Test conditions, power sources and ambient conditions
6.1 Normal and extreme test-conditions
Type tests shall be made under normal test conditions, and also, where stated, under extreme test
conditions.
The test conditions and procedures shall be as specified in subclauses 6.2 to 6.4.2.4.
6.2 Test power source
During type tests the power source of the equipment shall be replaced by a test power source, capable of
producing normal and extreme test voltages as specified in subclauses 6.3.2 and 6.4.2. The internal
impedance of the test power source shall be low enough for its effect on the test results to be negligible.
For the purpose of the tests, the voltage of the power source shall be measured at the input terminals of
the equipment.
For battery operated equipment, the battery shall be removed and the test power source shall be suitably
decoupled and applied as close to the equipment battery terminals as practicable. For radiated
measurements any external power leads should be arranged so as not to affect the measurements. If
necessary the external power supply may be replaced with the equipment's own internal batteries at the
required voltage, this shall be stated on the test report.
If the equipment is provided with a power cable or power socket, the test voltage shall be that measured at
the point of connection of the power cable to the equipment.
During tests the power source voltages shall be within a tolerance of < ± 1 % relative to the voltage at the
beginning of each test. The value of this tolerance can be critical for certain measurements. Using a
smaller tolerance provides a better uncertainty value for these measurements. If internal batteries are
used, at the end of each test the voltage shall be within a tolerance of < ± 1 % relative to the voltage at the
beginning of each test.
6.3 Normal test conditions
6.3.1 Normal temperature and humidity
The normal temperature and humidity conditions for tests shall be any convenient combination of
temperature and humidity within the following ranges:
- temperature: + 15°C to + 35°C;
- relative humidity: 20 % to 75 %.
When it is impracticable to carry out the tests under the conditions stated above, a note to this effect,
stating the actual temperature and relative humidity during the tests, shall be added to the test report.
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I-ETS 300 422: December 1995
6.3.2 Normal test power source voltage
6.3.2.1 Mains voltage
The normal test voltage for equipment to be connected to the mains shall be the nominal mains voltage.
For the purpose of this I-ETS, the nominal voltage shall be the declared mains voltage, or any of the
declared mains voltages, for which the equipment was designed.
The frequency of the test power source corresponding to the alternating current (ac) mains shall be
between 49 Hz and 51 Hz.
6.3.2.2 Nickel-cadmium cells
When the radio equipment is intended for operation from the usual types of nickel-cadmium cell the
nominal test voltage shall be 1,2 V per cell.
6.3.2.3 Other power sources
For operation from other power sources or types of battery (primary or secondary), the normal test voltage
shall be that declared by the equipment manufacturer and approved by the test laboratory. The values
shall be stated in the test report.
6.4 Extreme test conditions
6.4.1 Extreme temperatures
For tests at extreme temperatures, measurements shall be made in accordance with the procedures
specified in subclause 6.4.1.1, at - 10°C and + 45°C.
6.4.1.1 Procedures for tests at extreme temperatures
Before measurements are made the equipment shall have reached thermal balance in the test chamber.
The equipment shall be switched off during the temperature stabilising period. If the thermal balance is not
checked by measurements, a temperature stabilising period of at least one hour shall be allowed.
The sequence of measurements shall be chosen and the humidity content in the test chamber shall be
controlled so that excessive condensation does not occur.
Before tests at the higher temperatures, the equipment shall be placed in the test chamber and left until
thermal balance is attained. The equipment shall then be switched on for one minute in the transmit
condition, after which the equipment shall meet the specified requirements.
For tests at the lower extreme temperature the equipment shall be left in the test chamber until thermal
balance is attained, then switched to the standby or receive condition for one minute after which the
equipment shall meet the specified requirements.
6.4.2 Extreme test power source voltages
6.4.2.1 Mains voltage
The extreme test voltages for equipment to be connected to an ac mains source shall be the nominal
mains voltage + 10 %.
The frequency of the test power source corresponding to the ac mains shall be between 49 Hz and 51 Hz.
6.4.2.2 Re-chargeable battery power sources
When the radi
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