Cambridge O Level Computer Science · Syllabus 2210 · Data Representation
Sample Resolution
What is Sample Resolution?
The sample resolution is the number of bits used per sample when an analogue sound wave is converted to binary. More bits per sample record the amplitude more precisely, giving better sound quality but a larger file.
This definition is part of the Data Representation chapter in Cambridge O Level Computer Science.
Sample Resolution in context
Sound reaches a microphone as a continuously varying analogue wave. To store it, the wave is sampled: its amplitude is measured at regular intervals, each measurement is recorded as a binary value, and those values are stored in order. Two settings control the process. The sample rate is the number of samples taken in a second. The sample resolution is the number of bits used per sample. Increasing either one makes the stored recording a more accurate representation of the original wave — and increases the file size.
For an uncompressed sound file, the size in bits is the sample rate multiplied by the sample resolution multiplied by the duration in seconds. The logic is simple: the rate tells you how many samples there are each second, the resolution tells you how many bits each sample takes, and the duration tells you how many seconds there are. Multiply the three, then convert down to the unit asked for.
Common mistakes with Sample Resolution
- 5. Swapping sample rate and sample resolution. Why it fails They are different quantities with different units. Rate is samples per second; resolution is bits per sample. An "explain" answer that swaps them scores nothing even if the general idea is right. Fix Rate counts how often; resolution counts how precisely.
- M12. "Sample rate and sample resolution mean the same thing." Why it fails They are different quantities measured in different things. Rate counts samples per second; resolution counts bits per sample. Correct model Rate is how often the wave is measured; resolution is how precisely each measurement is recorded. Exam-safe "The sample rate is the number of samples taken in a second; the sample resolution is the number of bits used per sample." Test yourselfHideQ. Which one determines how many different amplitude levels are available?A. The sample resolution: n bits give 2n levels.
- M14. "Sample resolution is the volume." Why it fails Resolution is the number of bits available to describe each amplitude measurement, not the size of the amplitude itself. Correct model More bits per sample means each amplitude is recorded more precisely, not that the sound plays back louder. Exam-safe "The sample resolution is the number of bits per sample; it affects how accurately each amplitude is recorded, not how loud the playback is." Test yourselfHideQ. How many amplitude levels does a 4-bit sample resolution give?A. 24 = 16.
Questions students ask about Sample Resolution
What is the difference between sample rate and sample resolution?
Sample rate is the number of samples taken of an analogue sound wave in one second; sample resolution is the number of bits used to store each of those samples. Increasing the sample rate takes more measurements per second, so the recording follows the wave more closely; increasing the sample resolution records each amplitude more precisely. Both changes make the stored recording more accurate but increase the file size — the two settings must never be swapped in an answer.