A Level Computer Science AQA, Binary
Representation of Images and Sound
Exam With 100% Correct Answers
Describe how bit patterns may represent other forms of data, including graphics and sound. -
correct answers ✔✔Bit patterns can be used to store information about other forms of data, for
example images can be stored using the images height and width in pixels with the colour depth
and sound can be stored as digital samples of the original sound.
Understand the difference between analogue and digital data. - correct answers ✔✔Analogue
data is a continuous wave recorded in its original form, when analogue waveforms are sampled
at intervals and turned into a discrete set of numbers it produces digital data.
Understand the difference between analogue and digital signals.. - correct answers
✔✔Analogue: a continuous signal which represents physical measurements. Digital: discrete
time signals generated by digital modulation.
Describe the principles of operation of an analogue to digital converter (ADC) - correct answers
✔✔A microphone converts the sound energy into electrical energy. The ADC samples the
analogue data at a given frequency, measures the amplitude of the wave at each point and
converts it into a binary value using the resolution of each sample.
Describe the principles of operation of a digital to analogue converter (DAC). - correct answers
✔✔A digital signal is converted into an electrical signal which is then passes through an
amplifier, creating an analogue signal. Commonly used to convert a digital audio signal to an
analogue signal.
Explain the following for bitmaps: resolution - correct answers ✔✔Resolution is expressed as
number of dots per inch where a dot is a pixel.
Representation of Images and Sound
Exam With 100% Correct Answers
Describe how bit patterns may represent other forms of data, including graphics and sound. -
correct answers ✔✔Bit patterns can be used to store information about other forms of data, for
example images can be stored using the images height and width in pixels with the colour depth
and sound can be stored as digital samples of the original sound.
Understand the difference between analogue and digital data. - correct answers ✔✔Analogue
data is a continuous wave recorded in its original form, when analogue waveforms are sampled
at intervals and turned into a discrete set of numbers it produces digital data.
Understand the difference between analogue and digital signals.. - correct answers
✔✔Analogue: a continuous signal which represents physical measurements. Digital: discrete
time signals generated by digital modulation.
Describe the principles of operation of an analogue to digital converter (ADC) - correct answers
✔✔A microphone converts the sound energy into electrical energy. The ADC samples the
analogue data at a given frequency, measures the amplitude of the wave at each point and
converts it into a binary value using the resolution of each sample.
Describe the principles of operation of a digital to analogue converter (DAC). - correct answers
✔✔A digital signal is converted into an electrical signal which is then passes through an
amplifier, creating an analogue signal. Commonly used to convert a digital audio signal to an
analogue signal.
Explain the following for bitmaps: resolution - correct answers ✔✔Resolution is expressed as
number of dots per inch where a dot is a pixel.
