Audio Systems #1

Why are non-inverting operational amplifiers used in an Audio System?

• The have a very high bandwidth

• They have a very high input impedance

• The have a very high open loop gain

• They have a large gain-bandwidth product

In the diagram of an Audio System, what function would a non-inverting amplifier perform?

• Power amplifier

• Tone control

• Mixer

• Pre-amplifier

Which subsystem would be able to emphasise particular audio frequencies?

• Pre-amplifier

• Mixer

• Tone control

• Power amplifier

Which subsystem provides current to drive the loudspeaker?

• Mixer

• Tone control

• Power amplifier

• Pre-amplifier

To maximise voltage transfer from one subsystem to the next, how must the input impedance of the SECOND subsystem compare with the output impedance of the first subsystem?

• It must have a much smaller impedance

• It must have exactly the same impedance

• It must have a much larger impedance

• It doesn't really matter

Which of these ranges is correct for full audio bandwidth (for human ears!)?

• 0 Hz to 20 Hz

• 0 Hz to 20 kHz

• 20 Hz to 15 kHz

• 20 Hz to 20 kHz

For an amplifier with a given gain-bandwidth product (GBP), if you were to increase the gain what would happen to the amplifiers bandwidth?

• Nothing - it stays the same

• It increases

• It decreases

A pre-amplifier has a GBP of 1MHz and the gain is set to 200. What is its bandwidth?

• 1 MHz

• 500 Hz

• 5000 Hz

• 2000 Hz

• 200 MHz

From this pair of subsystems, calculate the total gain and bandwidth.

• Gain = 20, bandwidth = 100 kHz

• Gain = 400, bandwidth = 100 kHz

• Gain = 400, bandwidth = 10 kHz

• Gain = 40, bandwidth = 20 kHz

• Gain = 400, bandwidth = 20 kHz

From this pair of subsystems, calculate the total gain and bandwidth.

• Gain = 10, Bandwidth = 20 kHz

• Gain = 200, Bandwidth = 40 kHz

• Gain = 200, Bandwidth = 20 kHz

• Gain = 200, Bandwidth = 800 kHz

• Gain = 20, Bandwidth = 60 kHz