Difference Between QAM Signal and Digital Signal

QAM Signal vs Digital Signal

In today’s world, signals are integral in order to facilitate the communication of all our devices. However, there are many types of signals, and it is quite confusing to understand which are which and why they’re important. Presently, we’ll discuss QAM signals and how they differ from a digital signal. The main distinction between QAM and other digital signals is that QAM can either be analog or digital. That is, you can either use a digital modulating signal or an analog modulating signal with QAM.

QAM, or Quadrature Amplitude Modulation, is a technique for piggybacking a signal that contains the actual information to a carrier signal. This is used in transmission systems in order to maximize the bandwidth and provide proper separation so multiple signals in the same medium will not interfere with each other. The term “digital signal” is more general and applies to all signals that only switch between one and zero. In its digital form, QAM is also a digital signal, but digital signals are not limited to modulation. Just about any modern equipment uses digital signals to facilitate communication. A few examples of interface standards that use digital signals include HDMI and USB.

What makes QAM unique from other modulation techniques that use digital signals is that QAM uses two modulating signals at the same time to modulate two carrier waves. Most modulation techniques only use a single, digital stream to modulate a single carrier.

Quadrature Amplitude Modulation is so-called because it uses two signals that are 90 degrees out of phase and are those referred to as quadrature carriers. QAM changes both the amplitude of signals with respect to the first bit stream and the difference in phases between the two carriers with respect to the second bit stream. In this manner, QAM is capable of sending two digital signals at a time. At the receiver end, the independent signals are extracted by multiplying the signal with cosine or sine. Then it is just a matter of demodulating the two carriers in order to extract the data that was transmitted.

Summary:

1.A QAM signal can be an analog or digital signal.
2.QAM is used in modulation while a digital signal is used in many things.
3.A QAM signal can consist of two digital signals.

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