Acoustic Echo Cancellation Quiz

Answers and explanations appear as you take the quiz.

1. What problem does acoustic echo cancellation primarily solve?
   • Stopping a speaker's sound from being picked up by the microphone and sent back to the far end
   • Compressing audio files to save bandwidth
   • Translating speech into another language
   • Boosting the volume of quiet speakers
2. What 'reference' signal does an AEC system rely on to predict the echo?
   • The near-end speaker's microphone input
   • The far-end signal being played out of the speaker
   • A pre-recorded room template
   • Background noise levels
3. Which scenario is notoriously difficult for AEC and can cause an adaptive filter to misbehave?
   • Complete silence on both ends
   • A single person speaking slowly
   • Double-talk, when both parties speak simultaneously
   • Playing music with no one talking
4. What does the adaptive filter in classic AEC actually try to estimate?
   • The speaker's emotional tone
   • The Wi-Fi signal strength
   • The compression codec being used
   • The acoustic path (impulse response) from speaker to microphone in the room
5. Why are neural networks increasingly added on top of classical AEC filters?
   • To handle nonlinear distortion and residual echo that linear filters miss
   • To make calls more expensive
   • To replace the microphone hardware
   • To slow down processing for accuracy
6. Which adaptive algorithm is commonly associated with traditional echo cancellation?
   • RSA encryption
   • Normalized Least Mean Squares (NLMS)
   • JPEG compression
   • Dijkstra's algorithm
7. Why must an adaptive echo-path filter keep updating during a call?
   • The far-end reference changes its language every second
   • The microphone stops recording whenever a door opens
   • Room acoustics can change when people or objects move, changing the path from speaker to microphone
   • A fixed filter automatically learns new room conditions without updates
8. What kinds of recordings are included in Microsoft's AEC Challenge datasets?
   • Only music recorded in anechoic chambers
   • Only far-end speech with no microphone signal
   • Only speech with no echo or near-end speaker
   • Single-talk and double-talk recordings from real devices and speakers, plus synthetic data