Publication: Magyar Közlöny
Issue: MK-2009-104 (Year: 2009, Number: 104)
Era: 2004-2010
Section: 
Paragraph Index: 2157

2. Spurious emissions requirements begin at ±250 per cent of the 1.3 MHz value, therefore the transmit mask requirement extends to ±3.25 MHz. Figure 12-1. UAT transmit spectrum Frequency offset (M z) H –30 –20 –40 –50 –60 –70 dB below maximum UAT spectral mask 250% boundary Part I Annex 10 — Aeronautical Communications I-12-15 22/11/07 Figure 12-2. Time/amplitude profile of UAT message transmission Active Inactive Inactive T* ADS-B Message Transmission Interval Allowed power range for Equipment Class 20 dB -80 dBm Time in bit periods (1 bit period = 0.96 microseconds) *T = 276 for Short ADS-B T = 420 for Long ADS-B T = 4452 for Ground Uplink Annex 10 — Aeronautical Communications Volume III 22/11/07 I-12-16 Figure 12-3. Ideal eye diagram Figure 12-4. Distorted eye diagram ___________________ Well defined optimum sampling point. Well defined optimum sampling point. Well defined optimum sampling point. Poorly defined optimum sampling point. Poorly defined optimum sampling point. ANNEX 10 — VOLUME III II-1-1 22/11/07 INTERNATIONAL STANDARDS AND RECOMMENDED PRACTICES PART II — VOICE COMMUNICATION SYSTEMS CHAPTER 1. DEFINITIONS Note.— Material on secondary power supply and guidance material concerning reliability and availability for communication systems is contained in Annex 10, Volume I, 2.9 and Volume I, Attachment F, respectively. ___________________ ANNEX 10 — VOLUME III II-2-1 22/11/07 CHAPTER 2. AERONAUTICAL MOBILE SERVICE 2.1 AIR-GROUND VHF COMMUNICATION SYSTEM CHARACTERISTICS Note.— In the following text the channel spacing for 8.33 kHz channel assignments is defined as 25 kHz divided by 3 which is 8.3333 ... kHz. 2.1.1 The characteristics of the air-ground VHF communication system used in the International Aeronautical Mobile Service shall be in conformity with the following specifications: 2.1.1.1 Radiotelephone emissions shall be double sideband (DSB) amplitude modulated (AM) carriers. The designation of emission is A3E, as specified in the ITU Radio Regulations. 2.1.1.2 Spurious emissions shall be kept at the lowest value which the state of technique and the nature of the service permit. Note.— Appendix S3 to the ITU Radio Regulations specifies the levels of spurious emissions to which transmitters must conform. 2.1.1.3 The radio frequencies used shall be selected from the radio frequencies in the band 117.975 – 137 MHz. The separation between assignable frequencies (channel spacing) and frequency tolerances applicable to elements of the system shall be as specified in Volume V. Note.— The band 117.975 – 132 MHz was allocated to the Aeronautical Mobile (R) Service in the ITU Radio Regulations (1947). By subsequent revisions at ITU World Administrative Radio Conferences the bands 132 – 136 MHz and 136 – 137 MHz were added under conditions which differ for ITU Regions, or for specified countries or combinations of countries (see RRs S5.203, S5.203A and S5.203B for additional allocations in the band 136 – 137 MHz, and S5.201 for the band 132 – 136 MHz). 2.1.1.4 The design polarization of emissions shall be vertical. 2.2 SYSTEM CHARACTERISTICS OF THE GROUND INSTALLATION 2.2.1 Transmitting function 2.2.1.1 Frequency stability. The radio frequency of operation shall not vary more than plus or minus 0.005 per cent from the assigned frequency. Where 25 kHz channel spacing is introduced in accordance with Volume V, the radio frequency of operation shall not vary more than plus or minus 0.002 per cent from the assigned frequency. Where 8.33 kHz channel spacing is introduced in accordance with Volume V, the radio frequency of operation shall not vary more than plus or minus 0.0001 per cent from the assigned frequency. Note.— The above tolerances will not be suitable for offset carrier systems. Annex 10 — Aeronautical Communications Volume III 22/11/07 II-2-2 2.2.1.1.1 Offset carrier systems in 25 kHz, 50 kHz and 100 kHz channel spaced environments. The stability of individual carriers of an offset carrier system shall be such as to prevent first-order heterodyne frequencies of less than 4 kHz and, additionally, the maximum frequency excursion of the outer carrier frequencies from the assigned carrier frequency shall not exceed 8 kHz. Offset carrier systems shall not be used on 8.33 kHz spaced channels. Note.— Examples of the required stability of the individual carriers of offset carrier systems may be found at the Attachment to Part II. 2.2.1.2 POWER Recommendation.— On a high percentage of occasions, the effective radiated power should be such as to provide a field strength of a least 75 microvolts per metre (minus 109 dBW/m2) within the defined operational coverage of the facility, on the basis of free-space propagation. 2.2.1.3 Modulation. A peak modulation factor of at least 0.85 shall be achievable. 2.2.1.4 Recommendation.— Means should be provided to maintain the average modulation factor at the highest practicable value without overmodulation. 2.2.2 Receiving function 2.2.2.1 Frequency stability. Where 8.33 kHz channel spacing is introduced in accordance with Volume V, the radio frequency of operation shall not vary more than plus or minus 0.0001 per cent from the assigned frequency. 2.2.2.2 Sensitivity. After due allowance has been made for feeder loss and antenna polar diagram variation, the sensitivity of the receiving function shall be such as to provide on a high percentage of occasions an audio output signal with a wanted/unwanted ratio of 15 dB, with a 50 per cent amplitude modulated (A3E) radio signal having a field strength of 20 microvolts per metre (minus 120 dBW/m2) or more. 2.2.2.3 Effective acceptance bandwidth. When tuned to a channel having a width of 25 kHz, 50 kHz or 100 kHz, the receiving system shall provide an adequate and intelligible audio output when the signal specified at 2.2.2.2 has a carrier frequency within plus or minus 0.005 per cent of the assigned frequency. When tuned to a channel having a width of 8.33 kHz, the receiving system shall provide an adequate and intelligible audio output when the signal specified at 2.2.2.2 has a carrier frequency within plus or minus 0.0005 per cent of the assigned frequency. Further information on the effective acceptance bandwidth is contained in the Attachment to Part II. Note.— The effective acceptance bandwidth includes Doppler shift. 2.2.2.4 Adjacent channel rejection. The receiving system shall ensure an effective rejection of 60 dB or more at the next assignable channel. Note.— The next assignable frequency will normally be plus or minus 50 kHz. Where this channel spacing will not suffice, the next assignable frequency will be plus or minus 25 kHz, or plus or minus 8.33 kHz, implemented in accordance with the provisions of Volume V. It is recognized that in certain areas of the world receivers designed for 25 kHz, 50 kHz or 100 kHz channel spacing may continue to be used. Part II Annex 10 — Aeronautical Communications II-2-3 22/11/07 2.3 SYSTEM CHARACTERISTICS OF THE AIRBORNE INSTALLATION 2.3.1 Transmitting function 2.3.1.1 Frequency stability. The radio frequency of operation shall not vary more than plus or minus 0.005 per cent from the assigned frequency. Where 25 kHz channel spacing is introduced, the radio frequency of operation shall not vary more than plus or minus 0.003 per cent from the assigned frequency. Where 8.33 kHz channel spacing is introduced, the radio frequency of operation shall not vary more than plus or minus 0.0005 per cent from the assigned frequency. 2.3.1.2 Power. On a high percentage of occasions, the effective radiated power shall be such as to provide a field strength of at least 20 microvolts per metre (minus 120 dBW/m2) on the basis of free space propagation, at ranges and altitudes appropriate to the operational conditions pertaining to the areas over which the aircraft is operated. 2.3.1.3 Adjacent channel power. The amount of power from a 8.33 kHz airborne transmitter under all operating conditions when measured over a 7 kHz channel bandwidth centred on the first 8.33 kHz adjacent channel shall not exceed -45 dB below the transmitter carrier power. The above adjacent channel power shall take into account the typical voice spectrum. Note.— The voice spectrum is assumed to be a constant level between 300 and 800 Hz and attenuated by 10 dB per octave above 800 Hz. 2.3.1.4 Modulation. A peak modulation factor of at least 0.85 shall be achievable. 2.3.1.5 Recommendation.— Means should be provided to maintain the average modulation factor at the highest practicable value without overmodulation. 2.3.2 Receiving function 2.3.2.1 Frequency stability. Where 8.33 kHz channel spacing is introduced in accordance with Volume V, the radio frequency of operation shall not vary more than plus or minus 0.0005 per cent from the assigned frequency. 2.3.2.2 SENSITIVITY 2.3.2.2.1 Recommendation.— After due allowance has been made for aircraft feeder mismatch, attenuation loss and antenna polar diagram variation, the sensitivity of the receiving function should be such as to provide on a high percentage of occasions an audio output signal with a wanted/unwanted ratio of 15 dB, with a 50 per cent amplitude modulated (A3E) radio signal having a field strength of 75 microvolts per metre (minus 109 dBW/m2). Note.— For planning extended range VHF facilities, an airborne receiving function sensitivity of 30 microvolts per metre may be assumed. 2.3.2.3 Effective acceptance bandwidth for 100 kHz, 50 kHz and 25 kHz channel spacing receiving installations. When tuned to a channel designated in Volume V as having a width of 25 kHz, 50 kHz or 100 kHz, the receiving function shall ensure an effective acceptance bandwidth as follows:

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