LectComposition of Ship Global Maritime and Security System radio equipment [1, 3, 5, 7, 12]

The specified frequency is the average frequency of the carrier frequency band. The width of this frequency band is equal to the sum of the width of the required frequency band and 2 times the absolute value of the allowable frequency deviation. As a rule, the frequencies set in the information books are indicated.
The radiation class is a set of radiation characteristics denoted by conventional symbols. The division of radiation into classes consists of two parts, the new classification adopted by the ITU on the recommendations of the WARC-79 conference on the recommendations of the CCIR (International Radio Consultative Committee).
The first part consists of the main characteristic and the second part of the additional characteristics. In addition, another additional character group of four characters indicates the bandwidth and is written in front of the previous five characters. In general, the format of the written character set is as follows:
XXXX YYY ZZ
The width of the strip Radiation class Additional characteristics
Exsample: 134HJ2BCN, 2K70J3EJN, 304HF1BCN, 3M00PONAN
The width of the frequency band is denoted as in the example below: 304Н — 304Гц
2К70 — 2,7кГц
16К0 — 16 кГц.

In general, the radiation class is represented by three symbols.

1. 
   Type of basic carrier modulation (English letter).
   
2. 
   The nature of the modulating signal (number).
   
3. 
   Type of transmitted information (English letter).
   

In down below, there are the expressions of the main characters that characterize the radiation class.
A - two-lane;
H-single-band full carrier;
J- single-band weak carrier.

Radiation with angular modulation of the main carrier frequency:

F-frequency modulation; G-phase modulation Pulse radiation:

Sequence of non-P-modulated pulses

Angular modulation is used in radio communication in various frequency bands, in radio broadcasting in the VHF range, in voice broadcasting of television broadcasts, in radio relays, in the troposphere and in space communication. In addition, angle modulation is used in radio telemetry, radio control systems, a number of radionavigation and radar systems. In modern times, telegraph signals and digital information are transmitted mainly through frequency and phase manipulation. It is known that angular modulation provides better barrier resistance and higher energy characteristics than amplitude modulation. However, this requires wider frequency bands.