CEA CEA Signal Processing & Electronics 2

Question 1

What is the function of a phase-locked loop (PLL) in digital audio clock systems?

Accepted Answer

To lock a local clock to an incoming reference signal for synchronization

Answer

A PLL generates a local clock signal that precisely tracks an external reference, maintaining synchronization and minimizing jitter in digital audio systems.

Question 2

What is 'slew rate' in the context of operational amplifiers used in audio circuits?

Accepted Answer

The maximum rate of change of output voltage, typically expressed in V/µs

Answer

Slew rate describes how fast an op-amp's output can change voltage, and if it is too slow for the signal frequency, it causes slew-rate distortion.

Question 3

What is the primary purpose of a de-esser in audio signal processing?

Accepted Answer

To selectively reduce excessive sibilance ('s' and 'sh' sounds) in vocal recordings

Answer

A de-esser is a frequency-selective compressor that detects and attenuates harsh high-frequency sibilant energy in vocal recordings.

Question 4

In digital audio, what does 'jitter' refer to?

Accepted Answer

Timing variations in a digital clock signal that can cause sampling errors

Answer

Jitter is the deviation of a digital clock's transitions from their ideal timing positions, which can introduce noise and distortion in digital audio systems.

Question 5

What is the standard impedance of a professional balanced line-level output in audio?

Accepted Answer

50–200 Ω (low impedance)

Answer

Professional balanced outputs use low source impedance (typically 50–200 Ω) so they can drive long cable runs with minimal signal loss and noise pickup.

(CEA) Certified Audio Engineer Practice Test

(CEA) Certified Audio Engineer Practice Test

CEA CEA Signal Processing & Electronics 2