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MATLAB's documentation doesn't recommend the use of firrcos, instead use rcosdesign as recommend. Type doc firrcos in your command window, here are the first lines:
firrcos Raised Cosine FIR Filter design.
WARNING: firrcos is not recommended. Use RCOSDESIGN instead.
My guess is that firrcos is actually discontinued in new releases. To better help you, try ...
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In an actual received signal you will also have to address the frequency, phase and time offsets between the transmitter and receiver since they run off of independent clocks that aren’t otherwise synchronized, as well as frequency offsets introduced through Doppler if the transmitter and receiver are in motion relative to each other. Further information on ...
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Pulse shape filtering is used to constrain the signal bandwidth (with what would otherwise be a Sinc function in frequency given the rectangular pulse) and as a Nyquist filter done in such a way as to not introduce inter-symbol interference.
For CDMA and specifically direct-sequence spread spectrum in many cases we have no concern for spectral containment (...
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Preamble: This answer is about timing recovery in a sense of symbol synchronization, i.e. finding the proper sampling phase of a baseband signal.
Based on the stated requirement of only 8 samples per symbol, I will assume that you are employing a fully digital approach to timing recovery. That means that you have no control over the times of sampling by ADC. ...
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If you postulate that receiever's clock is perfect, then you want to make the transmitter send symbols every $T_s \pm \varepsilon$ seconds, where $T_s$ is the symbol period according to the receiver.
This is easily achieved by using a very high sampling rate in the transmitter. Let's assume $T_s=1$ and you need a deviation of $\pm 0.01$. This deviation ...
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With no filtering or pulse shaping what you have is your signal with the default rectangular pulse shape
$$
\Pi(t) = \begin{cases}1 & \text{for} & -\frac T2\leq t\leq \frac T2\\0 & \text{otherwise}\end{cases}
$$
Where $T$ is the symbol duration. The Fourier transform of the such a pulse result in a sinc function of the form
$$
H(f) = T\...
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I wanted to ask what are the techniques which can be used to extract this sub-band data?
That's a description of a filter bank.
Yes, the FFT can be used for such applications. You'll find that OFDM, which powers DVB-T, 4G/5G, WiFi, … (basically all high-speed wireless terrestrial links) does exactly that.
You'll also find that if you find the inherent sinc-...
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Question 1
All the antennas might get the same data (besides some phase shift as you noted), but they don't have to. In your picture, you have a blue beam and an orange beam that toggle on and off over time. There is nothing stopping you from using a subset of the antenna elements for each beam and transmit both simultaneously. For example, a 64 element ...
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From what I understand, the modulation is a QPSK at 72k symbol.
So the main lobe is 144 kHz wide.
First point: Shaping filter clarification
Do you know if there is a shaping filter used by the transmitter?
Usually it is an RRC filter with a roll off of a given value.
If there is one in the transmiter, your RRC filter in the receiver should match roll off ...
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IF a 1 is always represented by the waveform in the figure, you can use that waveform as the matched filter response.
However, it sounds like the waveform could be anything as long as there are some pulses in it. In that case, the matched filter should be a single pulse, and you'll have to count how many pulses were detected afterwards.
The non-Gaussian ...
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The raised-cosine filter impulse response is documented in many textbooks and in Wikpedia here. All you need to do is implement that impulse response in your C program.
If you are transmitting data, you should really be using a root raised-cosine filter (raised cosine pulses are not orthogonal). Their impulse response is here.
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Sampling Time offset is the disparity is the starting point of sampling, ie , sampling did not start at point "0".
Sampling frequency offset (SFO) is the error in the practical sampling frequency from what is required in paper. It is mainly due to practical limitations in generating perfect sampling pulses.
Carrier frequency offset (CFO) is the ...
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