Linked Questions

8 votes
5 answers
29k views

What is an Intuitive Explanation of the Phase of a Signal

I understand that the meaning of the phase response of a system is simply how much the system delays a frequency component. However, I do not find an intuitive explanation for the phase of a signal. ...
hbak's user avatar
  • 321
6 votes
2 answers
3k views

Recovering signal for psk

I am currently working on a product (can't disclose too much details of the actual project) in which some data is being sent via audible (but on the higher freq) sound that is encoded with dqpsk. ...
Wong Shek Hei Felix's user avatar
6 votes
1 answer
3k views

Obtain I/Q Components from a Real Signal On the Fly - Hilbert Transform or Digital Downconversion?

I'm planning to build a data acquisition system for a software-defined radio receiver. Basically, it just uses an ADC which samples an analog signal and send the signal to a processor. And then a ...
比尔盖子's user avatar
1 vote
2 answers
3k views

baseband and passband modulation

I have a simulink model over 2.4GHz. In the transmitter part, the modulation is O-QPSK modulated baseband instead of passband modulation. In Matlab Help this is the reason of using baseband ...
kate's user avatar
  • 13
4 votes
3 answers
1k views

Understanding I and Q modulation

As a newbie I am trying to understand I and Q modulation and demodulation. So from what I read the I and Q components of a signal separately mix with RF signals that are 90 degrees out of phase with ...
Jack's user avatar
  • 325
1 vote
2 answers
1k views

Intuitive meaning of complex time domain signal representation (quadrature sampling)

I saw What is the meaning of imaginary values in the time domain?. My question is about I Q samples as recorded from an SDR receiver (e.g. RTL-SDR). My understanding is that we can call these I Q ...
axk's user avatar
  • 237
0 votes
1 answer
1k views

How is quadrature mixing done?

I've a Gaussian modulated signal whose quadrature and in phase components are separated. I'm multiplying these components with quadrature and in phase components of a signal of 10MHz frequency, ...
Sumbul's user avatar
  • 337
0 votes
2 answers
280 views

Why Shannon Theorem has nothing to do with frequency?

According to Shannon theorem $$C= B \log _2(1 + S/N)$$ My question is, why there is no frequency in this formula? Let's say we have 2 channels, both of them have same 20 MHz bandwidth, one is from ...
Kyung Lee's user avatar
  • 103
0 votes
3 answers
1k views

OFDM SubCarrier and its relationship with IFFT in context of Real and Complex

In the process of OFDM Signal generation. We take symbols (constellation symbols) and map it to a sub-carrier (real analog time domain) harmonics of 15khz, add different sub-carriers separated by ...
Reddi Suresh's user avatar
1 vote
3 answers
466 views

Can Carrier Offset cause Image Problems

The main reason why we use the Direct conversion receiver with zero IF is that we don't have to deal with the problem of images. For achieving zero IF we need to ensure that the receiver Local ...
sarthak's user avatar
  • 303
1 vote
2 answers
866 views

Software PLL tracking of carrier frequency in bandlimited transmission

My understanding is that a PLL(either in hardware or software) can recover the carrier frequency(or be used to correct the frequency offset) of a system. My question is how does this work when the ...
FourierFlux's user avatar
2 votes
3 answers
254 views

Effects of interchanging sine terms with cosine terms

Suppose we have a real signal $x(t)$. Now, we know that $x(t)$ can be represented as a sum of sines and cosines. w be the angular frequency. If $a(\omega)$ be the coefficients of the cosine terms, ...
Ayush Pandey's user avatar
0 votes
1 answer
460 views

Shift of the signal spectrum to the desired frequency

I have a task to select only the area I need from the signal and shift its spectrum. I am digitizing the signal at 48kHz. A useful signal for me is in the region of 5500-5995Hz and 6005-6500Hz. In ...
red15530's user avatar
0 votes
1 answer
428 views

Code Snippet to Convert ADC Samples to I/Q

I'd like to pull a narrowband signal out of ADC samples, where the ADC rate is much higher than the bandwidth/central frequency of the narrowband signal. I'd like to feed the narrowband signal into a ...
jsievers's user avatar
0 votes
3 answers
378 views

OFDM Signal and IQ Paths

I understand that we have analog complex signal after it passes DAC after coming out of IFFT in OFDM Transmitter. After that we do orthogonal upconversion on it and send it. I've question now for OFDM ...
Reddi Suresh's user avatar

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