Pulse code modulation (PCM) is used to encode a high-resolution laboratory recording of bat echolocation calls using a specialized tri-channel (3-channel) microphone array. The acoustic signals are sampled at a frequency of 192 kHz192\text{ kHz}192 kHz using a 20-bit20\text{-bit}20-bit encoding system.
Explain why the sampling frequency used is suitable for this task, given that the highest frequency of interest in the bat calls is 60 kHz60\text{ kHz}60 kHz.
Calculate the number of quantisation levels available on this 20-bit20\text{-bit}20-bit encoding system.
A recorded tri-channel audio clip lasts for 4.0 minutes4.0\text{ minutes}4.0 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 recording.
The recorded file is transmitted to a base station over a satellite telemetry link. This transmission network limits the frequency range of the transmitted signal to 100 Hz−45 kHz100\text{ Hz} - 45\text{ kHz}100 Hz−45 kHz. Compare the quality of the telemetry-transmitted signal with that of the original laboratory digital recording.
