# Tag Info

## Hot answers tagged digital-communications

4 votes

### Help me understand the concept of IQ signals

The important takeaway is: using a radio, you can transmit two signals "at the same time" (technically: over the same bandwidth). One of the signals is known as I (in-phase), the other as Q (...
• 14.9k
2 votes

### Help me understand the concept of IQ signals

It might be best to compare an IQ signal with complex numbers, or circle on an XY plane, or phasors. As the IQ signal is a sum of sine wave with some amplitude and cosine wave with some amplitude, the ...
• 2,278
2 votes
Accepted

### How is the normalized power required for unipolar NRZ twice that of polar NRZ?

If the levels of the polar signal were $\pm V$ you would be right, but then it wouldn't be a fair comparison with the unipolar signal with levels $+V$ and zero. A fair comparison would be to have the ...
• 88.9k
1 vote

### Help me understand the concept of IQ signals

In SDRs, multiplying a real-valued bandpass signal by a cosine wave, and simultaneously multiplying that real-valued bandpass signal by a sine wave, generates a complex-valued signal that has been ...
• 5,577

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