GMDSS: Element 3

1. A A standard pulse is varied in amplitude by an amount depending on the voice waveform at that instant.
2. B The position of a standard pulse is varied by an amount depending on the voice waveform at that instant.
3. C A standard pulse is varied in duration by an amount depending on the voice waveform at that instant.
4. D The number of standard pulses per second varies depending on the voice waveform at that instant.

Tip: press A-D to answer