What is the amplitude of a sound wave?

Amplitude is the height of the sound wave at a given moment. A larger amplitude gives a louder sound.

What is the sample rate?

The sample rate is the number of samples taken each second. The sample rate is measured in hertz (Hz).

What is the sample interval?

The sample interval is the time between one sample and the next. The interval equals 1 ÷ sample rate.

What is the sample interval for a sample rate of 1,000 Hz?

The sample interval is 1 millisecond. The interval is 1 ÷ 1,000 = 0.001 seconds.

Edexcel GCSE Computer Science 1CP2

Computational Thinking

Topic overview Decomposition, abstraction and subprograms Algorithms, flowcharts and pseudocode Operators and trace tables Logic errors, test data and efficiency Searching and sorting algorithms Truth tables

Data

Topic overview Binary, states and unsigned integers Two's complement Binary addition, overflow and shifts Hexadecimal ASCII and the limits of binary representation Bitmap images Sound sampling Storage units, file sizes and compression

Computers

Topic overview Von Neumann architecture and the fetch-decode-execute cycle Secondary storage: magnetic, optical and solid state Embedded systems Operating systems Utility software and robust software Low-level and high-level languages and translators

Networks

Topic overview LANs, WANs and the structure of the internet Wired and wireless connectivity and network speed Network protocols The four-layer TCP/IP model Bus, star and mesh topologies Network security and protection

Issues and Impact

Topic overview Environmental impact of digital devices Personal data: privacy, ownership and consent Artificial intelligence, machine learning and robotics Intellectual property: copyright, patents, trademarks and licences Malware, hacking and social engineering Protecting digital systems and data

Problem Solving with Programming

Topic overview Readable code, debugging and testing Selection and loops in Python Data types, conversion, variables and constants String handling Lists, two-dimensional lists and records Keyboard input, screen output and CSV files Validation and authentication in Python Operators, functions and variable scope Turtle graphics

Data

Sound sampling

3 things to know
Paper 1

Overview

How analogue sound is sampled, amplitude, sample rate, sample interval and bit depth, their effect on quality and size, and worked sound file calculations.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

How do the sample rate and the sample interval of a recording differ?

Key term

Why must analogue sound be converted before a computer can store it?

Key term

How is analogue sound converted into binary?

Questions from this subtopic

Each one with the model answer underneath.

1
Why must analogue sound be converted before a computer can store it?
Model answer
Analogue sound is a continuous wave that varies smoothly over time. A computer can only store discrete binary values, so the wave must be sampled.
2
How is analogue sound converted into binary?
Model answer
The amplitude of the sound wave is measured at regular intervals. Each measurement, called a sample, is stored as a binary number.
3
What is the amplitude of a sound wave?
Model answer
Amplitude is the height of the sound wave at a given moment. A larger amplitude gives a louder sound.
4
What is the sample rate?
Model answer
The sample rate is the number of samples taken each second. The sample rate is measured in hertz (Hz).
5
What is the sample interval?
Model answer
The sample interval is the time between one sample and the next. The interval equals 1 ÷ sample rate.
6
What is the sample interval for a sample rate of 1,000 Hz?
Model answer
The sample interval is 1 millisecond. The interval is 1 ÷ 1,000 = 0.001 seconds.

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