← Digital & Analogue
2.4 Digital Analogue

Build the complete signal chain for recording and playing back audio. Click components from the bank to add them to your signal path in the correct order. Click a placed component to remove it.

Components Bank (click to add)
All components placed.
Your Signal Path (click to remove)
Click components above to build your signal chain.

Key Definitions

Transducer
A device that converts energy from one form to another. A microphone converts acoustic energy to electrical energy. A speaker does the reverse.
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Anti-Aliasing Filter
An analogue lowpass filter applied before the ADC to remove frequencies above the Nyquist frequency, preventing aliasing artefacts in the digital signal.
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ADC (Analogue-to-Digital Converter)
Converts the analogue electrical signal into digital binary data through sampling and quantisation. Found in audio interfaces.
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DAC (Digital-to-Analogue Converter)
Converts digital binary data back into a continuously varying analogue electrical signal for playback. Produces a stepped output that needs filtering.
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Reconstruction Filter
An analogue lowpass filter placed after the DAC that smooths the stepped staircase output into a continuous waveform by removing high-frequency artefacts.
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Signal Chain
The complete path audio travels: Acoustic sound > Microphone > Anti-aliasing filter > ADC > Digital processing > DAC > Reconstruction filter > Amplifier & Speakers > Acoustic sound.
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Why This Matters for the Exam

Signal chain ordering questions appear regularly in Edexcel papers. You need to know the seven-stage sequence and understand that both filters are analogue and sit immediately either side of their respective converter. Remember: a digital signal must always be converted back to analogue before you can hear it.

What you learned

  • Place the components of the recording signal chain in the correct order
  • Identify where ADC and DAC sit in the signal path
  • Explain the role of anti-aliasing and reconstruction filters
  • Distinguish between acoustic, analogue, and digital domains in the chain
← Digital & Analogue