An underwater acoustic monitoring station uses Pulse Code Modulation (PCM) to record the low-to-mid frequency vocalizations of marine mammals. The analogue hydrophone signals are sampled at a rate of 22 kHz22\text{ kHz}22 kHz. A 16-bit analogue-to-digital converter (ADC) is used to digitize each channel of a 3-channel (tri-axial) sensor array.
Explain why the sampling frequency of 22 kHz22\text{ kHz}22 kHz is suitable for this task, given that the maximum frequency of interest in the mammal vocalizations is 8.0 kHz8.0\text{ kHz}8.0 kHz.
Calculate the number of quantisation levels available in this 16-bit encoding system.
A continuous recording session lasts for 12 minutes12\text{ minutes}12 minutes. Calculate the size, in megabytes (using 1 MB=106 bytes1\text{ MB} = 10^6\text{ bytes}1 MB=106 bytes), of the uncompressed digital file needed to store this multi-channel recording.
The digitized data is transmitted live to a research vessel via an acoustic modem. However, the underwater acoustic communication channel limits the bandwidth of the transmission to a frequency range of 150 Hz−5.5 kHz150\text{ Hz} - 5.5\text{ kHz}150 Hz−5.5 kHz. Compare the quality and spectral content of the acoustic data received at the vessel with the original recorded digital data.
