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ETS 300 441: February 1996
-
modulation off:
250 ms
±
50 ms.
8.2.4
Response to the 1 300 Hz EPIRB signal
An A2A test signal at the carrier frequency 2 182 kHz modulated to a depth of 30 % at 1 300 Hz and
having a pulse sequence of one second signal followed by one second no signal shall be applied to the
receiver input. The level shall be below that necessary to lift the mute. The output power shall be
measured whilst the level of the input test signal is increased until the output power rises to at least - 6 dB
relative to standard output power.
The input level at which this occurs shall be recorded.
The test shall be repeated at all combinations of the limits given below:
-
modulation frequency:
1 300 Hz
±
20 Hz;
-
modulation and carrier on:
1,0 s - 1,2 s;
-
modulation and carrier off:
1,0 s - 1,2 s; and
omitting those combinations resulting in mark/space ratios below 1/1.
8.2.5
Limit
The mute shall be lifted within a period not greater than six seconds at input levels equal to and higher
than the measured sensitivity level.
8.3
Protection against unwanted signals
8.3.1
Method of measurement
The receiver shall be adjusted in accordance with subclause 8.2.1, after which the tests as described
below shall be carried out with the mute set to the operative condition.
8.3.1.1
Selective calling signals on 2 170,5 kHz
An A2A test signal at the carrier frequency 2 170,5 kHz with a duration of at least 10 seconds modulated
to a depth of 70 % shall be applied to the receiver input at a level of 70 dB above the measured sensitivity
level. The modulation frequency shall alternate between 1 275 Hz and 2 110 Hz, each pulse having a
duration of 100 ms. The output power shall be measured.
The measurement shall be repeated with modulating frequencies 1 358 Hz and 2 110 Hz.
8.3.1.2
Speech modulation
A speech signal at the frequency 2 182 kHz and with a level 70 dB above the measured sensitivity level
shall be applied to the input of the receiver for a duration of five minutes. The output power shall be
measured.
8.3.1.3
Non-specific 2 200 Hz signals
An A2A signal, at the carrier frequency of 2 182 kHz modulated to a depth of 70 % shall be applied to the
receiver input at a level of 70 dB above the measured sensitivity level. The modulation frequency shall be
2 200 Hz ± 35 Hz and shall be pulsed using all combinations of the following:
a)
modulation on:
-
175 ms or less;
-
325 ms or greater;
