Modulator and Demodulator (conceptual question)?

• neotriz
In summary, the conversation discusses the output of a sinusoidal signal going through a modulator and demodulator. The ideal result would be an output that exactly matches the original signal, but in reality the output may have an attenuated amplitude. The expected amplitude was A/4 due to an ideal circuit diagram with specified gain values for the modulator and demodulator.

neotriz

Just a quick conceptual question.

If you have a sinusoidal signal of 3kHz with an amplitude of A, and it's going through a modulator, and then going through a demodulator, must the output of the modulator resemble exactly to the original signal?

The reason why I am asking is because when I was doing this in my lab, the output of the modulator had the same frequency of the original signal, but 1/10 of the Amplitude.

I thought it would have A/4 instead.

It all depends on your system.

A perfect modulator and demodulator would result in an output that exactly matched the original signal.

In reality the demodulator stage may be such that you get a demodulated signal has an attenuated amplitude. Ideally this attenuation would be known and linear so that you can amplify the signal back to its original state.

So I guess I would say I need more detail to really answer better than that. Why did you expect A/4 to begin with? What type of modulation were you performing?

Never mind, I just calculated the gain for the modulator and demodulator.

The reason I thought it would be A/4 is because I remembered the professor gave us an ideal circuit diagram that had a specified gain value for both the modulator and demodulator.

1. What is a modulator and demodulator?

A modulator and demodulator, also known as a modem, is a device that converts digital signals from a computer into analog signals for transmission over telephone lines, and then converts them back to digital signals at the receiving end.

2. How does a modem work?

A modem works by encoding digital data into analog signals, using a technique called modulation. These analog signals can then be transmitted over a telephone line. At the receiving end, the modem decodes the analog signals back into digital data using demodulation, allowing the data to be read by the computer.

3. What are the different types of modulation used by modems?

The most commonly used modulation techniques in modems are amplitude modulation (AM) and frequency modulation (FM). Other techniques include phase modulation (PM) and quadrature amplitude modulation (QAM).

4. What are the advantages of using a modem?

Modems allow for high-speed data transmission over existing telephone lines, making it possible to access the internet and send/receive large amounts of data. They also provide a reliable and cost-effective means of communication.

5. Can a modem be used for other types of communication?

Yes, modems can be used for other types of communication besides internet connection. They can be used for transmitting data over radio waves, satellite signals, and even optical fibers. They are also used in various industries for remote monitoring and control of systems.