Your input signal is a mono audio signal that is the output of an electret conde

Question

Your input signal is a mono audio signal that is the output of an electret condenser microphone. An

electret condenser microphone output always includes a DC offset in addition to the signal itself.

Suppose that this microphone outputs a signal with a voltage swing of 200 mVpp plus a DC offset of 5

V. This microphone output signal needs to be changed before being input to a sensitive audio

circuit. Specifically, it needs to be inverted, amplified, and the DC offset needs to be

removed. Design and build a circuit that will cancel out the DC offset and achieve

maximum signal amplification without exceeding the 20 Vpp input limit of the audio

equipment.

Model the output of this microphone as

0.1 sin(2?

Explanation / Answer

DC offset is usually undesirable when it causes saturation or change in the operating point of an amplifier. An electrical DC bias will not pass through a transformer; thus a simple isolation transformer can be used to block or remove it, leaving only the AC component on the other side. In signal processing terms, DC offset can be reduced in real-time by a high-pass filter. When one already has the entire waveform, subtracting the mean amplitude from each sample will remove the offset. Often, very low frequencies are called "slowly changing DC" or "baseline wander"

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.