DSBSC Multiplier modulator - Amplitude Modulation and Demodulation - Communication Engineering | Summary and Q&A

TL;DR

This content explains the concept of double sideband with suppressed carrier multiplier modulation, where the carrier signal is heavily suppressed, resulting in an amplitude modulated envelope consisting of only two sidebands.

Key Insights

• 💌 Double sideband with suppressed carrier multiplier modulation is a modulation technique that heavily suppresses the carrier signal, resulting in an envelope with only two sidebands.
• 🌉 DSB-SC multiplier modulation utilizes a bridge rectified circuit and a coupling transformer to achieve modulation.
• 📡 During different phases of the carrier signal, the message signal is multiplied by +1 and -1, respectively.
• 💌 DSB-SC multiplier modulation results in a 180-degree phase shift in the modulated envelope.
• 😑 The final expression for DSB-SC multiplier modulation involves the carrier frequency, the message signal, and a summation of terms.
• 💁 By suppressing the carrier signal, DSB-SC multiplier modulation can transmit information using only the sidebands.
• ✖️ DSB-SC multiplier modulation is a type of amplitude modulation technique.

Transcript

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Questions & Answers

Q: What is double sideband with suppressed carrier multiplier modulation?

Double sideband with suppressed carrier multiplier modulation is a modulation technique where the carrier signal is heavily suppressed, resulting in an envelope with only two sidebands and no carrier signal.

Q: How does DSB-SC multiplier modulation work?

In DSB-SC multiplier modulation, a bridge rectified circuit is used. During the positive half cycle of the carrier signal, the message signal is multiplied by +1, and during the negative half cycle, it is multiplied by -1. This results in a modulated envelope with a 180-degree phase shift.

Q: What is the purpose of using a coupling transformer in DSB-SC multiplier modulation?

The coupling transformer is used to couple the input and output of the bridge rectified circuit. It helps in transferring the modulating signal and the carrier signal effectively.

Q: What is the final expression for DSB-SC multiplier modulation?

The final expression for DSB-SC multiplier modulation is s(t) = 4/π * ∑(n=1 to infinity) [(-1)^(n-1) * cos(2πfct * (2n-1)) * m(t)], where s(t) is the modulated signal, fct is the carrier frequency, and m(t) is the message signal.

Summary & Key Takeaways

• Double sideband with suppressed carrier (DSB-SC) multiplier modulation is a technique where the carrier signal is heavily suppressed, resulting in an amplitude modulated envelope with only two sidebands.

• In DSB-SC multiplier modulation, a bridge rectified circuit is used, with the modulating signal and carrier signal applied.

• During the positive half cycle of the carrier signal, the message signal is multiplied by +1, and during the negative half cycle, it is multiplied by -1.