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6 votes
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How do I convert a real baseband signal to a complex baseband signal?

To convert a real signal sampled at rate $2B$ to its complex baseband representation (sampled at rate $B$), you want to map the frequency content in the range $[0, B)$ in the real signal to the range $...
Jason R's user avatar
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6 votes
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Building a data acquisition system to capture raw IQ data

As a front-end radio designer with experience in the microwave frequency ranges, I concur with the advice to just buy a solution such as the ADALM-PLUTO SDR Learning Module. However that particular ...
Dan Boschen's user avatar
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5 votes
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Why is the carrier suppressed by AM-DSB-SC modulation?

It's a simple trigonometric identity: $$\cos(\omega_mt)\cos(\omega_ct)=\frac12\left[\cos((\omega_m+\omega_c)t)+\cos((\omega_m-\omega_c))\right]\tag{1}$$ Multiplying two sinusoids of different ...
Matt L.'s user avatar
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5 votes
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Recommendation for good ressources on digital processing and D-QPSK

Wow, I'm honored by Matt L. doing what I'm often doing: Referring people to GNU Radio. The project actually has a list of recommended literature, but I don't know how well that'd fit you. It's ...
Marcus Müller's user avatar
5 votes

Building a data acquisition system to capture raw IQ data

Can you use any of the NI DAQ modules? Or does it need to be designing/soldering an RF front end from scratch and then reading it on some embedded processor/doing some FPGA? I think option (1) is ...
Ash SDR's user avatar
  • 133
5 votes

Building a data acquisition system to capture raw IQ data

I'd suggest buying a Adalm Pluto board. It's very inexpensive.
Dan CaJacob's user avatar
5 votes

Building a data acquisition system to capture raw IQ data

As Dan mentioned , check ADAM Pluto This might be a good starting point . I didn't look at the lab tutorials 1 and 2 and electronic tutorials 1 and 2 , but looks promising. You can probably order the ...
Ash SDR's user avatar
  • 133
4 votes
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How to accurately model wideband RF reflections?

So, to give you something to read up on first, the channel you describe is a Rician or Rayleigh channel, depending on whether you have a dominant line-of-sight path or not. So, as a first approach, ...
Marcus Müller's user avatar
4 votes

Real world application of signal sparsity?

Sparsity concept is extensively being used in computer vision and image processing. The Idea is that natural image can be pretty sparse when it is transformed to different bases. this bases can be ...
DoronPor's user avatar
  • 139
4 votes
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Possible to Derive Receive Signal Power from RSSI?

I also read this from a response to a USRP user's question about RSSI measurements: [The] Received Signal Strength [Indicator is] always relative to some signal model, incorporating ...
Marcus Müller's user avatar
4 votes
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Why do ATSC channels need 6MHz of bandwidth when they're digital?

A key point is bandwidth is proportional to the symbol rate, or rate of change of the modulation. If the symbol is rectangular shaped, the spectrum is a Sinc function with the first null in Hz at the ...
Dan Boschen's user avatar
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4 votes

Undestanding antenna gain applicability

The answer has to do with the definitions of antenna gain and space loss. Antenna "gain" is essentially defined relative to space loss, which is due to isotropic (uniform spherical) ...
Gillespie's user avatar
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4 votes
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Undestanding antenna gain applicability

Of course, the gain of an antenna is not like that of an op-amp. It is just a measure of how sharply it focuses the beam in a specific direction with regards to a reference antenna, e.g., an isotropic ...
Karakoncolos's user avatar
3 votes
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Wireless Channel Multiplicative Model

What's labeled $(1)$ in your question is a special case, the flat channel. It can be represented as a single coefficient. In general, channels aren't flat, and we then need to apply $(2)$ instead. ...
Marcus Müller's user avatar
3 votes
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Why is In-phase Quadrature sampling not used to record and store digital audio?

It is because the audio signals are real and already at baseband. In contrast radio frequency signals are often represented as complex numbers once they are brought back to baseband. Real signals can ...
Dan Boschen's user avatar
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3 votes
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Trouble with time-syncing two radio signals using cross-correlation

It will work when you take the 2nd gradient of the signals: ...
Marco's user avatar
  • 46
3 votes

If you had supersonic hearing, would you be able to hear the carrier wave of an AM radio station?

The AM or medium wave band extends from 526.5 kHz to 1606.5 kHz in Europe or 535 kHz to 1705 kHz in the US. Ultrasound (not supersound! :-) frequencies range from 20kHz and up: However, a bigger ...
Peter K.'s user avatar
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3 votes

fmcw radar sampling requirements

Your 2. is (as far as I know) the standard way to implement a FMCW radar. The major advantage of both the FMCW and the SFCW (which was mentioned in the comments), is the sample rate of the ADC is ...
oystein's user avatar
  • 185
3 votes

Measuring signal phase difference between receivers

Preface First of all: Arduino might really not be the tool of choice here; with a 1MS/s max, and some something-in-between-8-and-16-effective-bits ADC, there's hard limits on what you can detect. I ...
Marcus Müller's user avatar
3 votes
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Difference between slow, medium, fast AGC

I don't believe there is much more to it than that, especially noting that you are aware not to track so fast that you track out amplitude information for modulated signals where the amplitude is used ...
Dan Boschen's user avatar
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3 votes
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Does Radio Communication Have to Account for the Doppler Effect?

Does radio communication have to account for the doppler effect? Yes. Would be pretty terrible if that wasn't the case: RADAR wouldn't work! Do moving objects such as planes and rockets have to ...
Marcus Müller's user avatar
3 votes

How a diode-detector affects to Frequency Response?

But what does detector in the frequency domain? Something really complicated. We get trained to think about signal processing almost exclusively in the frequency domain, and we forget that the ...
TimWescott's user avatar
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3 votes

Why is GPS 1575 MHz?

The technical decision was to use L-Band which extends from 1-2 GHz. The specific frequencies to use within L-Band depended on political decisions including existing allocations and users of those ...
Dan Boschen's user avatar
  • 51.9k
3 votes
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The transmission distance of a signal

In principle, you can always test your channel and adjust your power according to the channel state before sending any signal. Each channel is always unique regardless of being in a city or in more ...
Mundo's user avatar
  • 171
3 votes
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Is digital (discrete) SSB plausible?

Ah, basically everything modern could be understood as single-sideband. The name is > 100 years old and was based off the fact that traditionally, all you could do on RF is take a single real-...
Marcus Müller's user avatar
3 votes
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Is BPSK relevant, or does it even exist, in wireless data transmission?

You are mostly correct. The main problem is that the introductory textbook definition of BPSK as a train of square pulses multiplied by a carrier is so simplistic that it hides what is really going on....
MBaz's user avatar
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2 votes
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Real world application of signal sparsity?

Sparsity covers a wide range of concepts. It characterizes an object (a signal, a system, a function) for which their exists a representation (exact or approximate) whose dimension (number of ...
Laurent Duval's user avatar
2 votes

Real world application of signal sparsity?

A couple of example areas: Sonar beamforming - in many cases there are a small number of targets Radar processing - a radar image can be decomposed to a background and sparse set of point like ...
David's user avatar
  • 2,871
2 votes
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Why is Error Vector Magnitude (EVM) measured as an RMS value?

You've got it – zero mean noise still has power. That power happens to be its variance. RMS of such signals thus happens to be the noise amplitude's standard deviation – and give a sensible number to ...
Marcus Müller's user avatar

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