Question 1: Explain what is meant by 'sampling' in digital sound representation.

Answer: Sampling is the process of measuring the amplitude of an audio signal at regular time intervals to convert it into digital form.

Question 2: Describe how increasing the bit depth affects the quality and file size of a digital audio recording.

Answer: Increasing the bit depth improves the audio quality by allowing more precise representation of amplitude levels, resulting in a higher dynamic range. However, it also increases the file size because more bits are used per sample.

Question 3: A sound wave is sampled at 44,100 times per second with a bit depth of 16 bits. Calculate the approximate size in megabytes of 10 seconds of recorded audio in uncompressed PCM format.

Answer: Size = sample rate × bit depth × duration in seconds / 8 (bits to bytes) / 1,048,576 (bytes to MB). = 44,100 × 16 × 10 / 8 / 1,048,576 ≈ 0.084 MB.

Question 4: Explain why higher sampling rates, like 96,000 Hz, are used in professional audio recording.

Answer: Higher sampling rates capture more detail of the sound wave, allowing for better sound quality and more accurate reproduction, especially for high-frequency sounds.

Question 5: Draw a simple logic circuit using AND, OR, and NOT gates that outputs true only when either input A or input B is true, but not both.

Answer: A circuit that implements XOR logic: an OR gate followed by an AND gate with a NOT gate to eliminate the case where both inputs are true. The correct circuit includes an OR gate, two AND gates, and a NOT gate connected appropriately to produce XOR output.

Question 6: Complete the truth table for an AND gate with inputs A and B and output C.

Answer: A | B | C 0 | 0 | 0 0 | 1 | 0 1 | 0 | 0 1 | 1 | 1

Question 7: Describe how a digital-to-analogue converter (DAC) would use binary data to produce sound signals.

Answer: A DAC converts binary digital data into an analogue voltage signal. It reads the binary value, which corresponds to a specific voltage level, and outputs that voltage to drive a speaker or audio device, reproducing the sound wave.

Question 8: Sketch a block diagram showing the key components involved in capturing and playing back digital sound, including the microphone, ADC, digital processor, DAC, and speaker.

Answer: A block diagram with the microphone connected to an ADC, which connects to a digital processor. The processor connects to a DAC, which outputs to a speaker. Label each component clearly.

Question 9: Identify and explain two advantages of using digital sound over analogue sound.

Answer: Digital sound can be easily stored and copied without loss of quality, and it allows for editing and processing using software, unlike analogue sound which degrades with each copy and is more susceptible to noise.

Question 10: Explain what is meant by the term 'bit depth' in digital audio and how it affects the quality of sound.

Answer: Bit depth refers to the number of bits used to represent each sample of audio. A higher bit depth allows for more precise representation of the amplitude, resulting in better sound quality with less quantization noise.