Question #3
An audio amplifier has the following frequency response:
At 50 Hz, gain = 30 dB.
At 100 Hz, gain = 37 dB.
At 200 Hz, gain = 40 dB.
At 1,000 Hz, gain = 40 dB.
At 10 kHz, gain = 40 dB. kHz,
At 12 kHz gain = 37 dB.
At 15 kHz, gain = 30 dB.
The gain of the amplifier is constant from 200 Hz to 10 kHz.
a. What is the 3 dB bandwidth of the amplifier, in kHz?
b. What is the 10 dB bandwidth of the amplifier in kHz?
c. A 1 kHz sine wave signal with a power level -20 dBm is applied to the input of the amplifier.
What is the power at the amplifier output in dBW?
d. A 12 kHz sine wave signal with a power level -20 dBm is applied to the input of the amplifier. What is the power at the amplifier output in dBW?
Question #4
A filter has the following characteristics:
Attenuation is 0 dB from 0 Hz to 2.5 kHz. The phase angle decreases linearly with increasing frequency above 2.5 kHz. Above 5 kHz the filter has steadily increasing attenuation. At 10 kHz attenuation is 6 dB and at 20 kHz attenuation is 24 dB
a. Is this a low pass, high pass, band pass or band stop filter?
b. What is the attenuation per octave between 10 kHz and 20 kHz?
c. If the filter is known to be a Butterworth filter, what is the value of its order, N?
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