Questions tagged [dsss]
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8 questions
0 votes
0 answers
85 views
What order should the DSSS spreader and mapper be in?
In a DSSS transmitter, what is the correct order of spreading and mapping (e.g. QPSK mapping)? Are there many different ways of implementing spreading? Many references suggest spreading first, many ...
- 246
2 votes
0 answers
100 views
Pulse-shaping filter for DSSS
In a direct-sequence spread-spectrum (DSSS) transmitter, each symbol is "spread" by a spreading sequence, $\mathbf{s}$. This increases the sample rate by a factor of $L_{s}$, where $L_{s}$ ...
- 246
0 votes
2 answers
110 views
Issues with Early-Late Discriminator in DS-CDMA Receiver
I am developing a receiver for a DS-CDMA signal modulated with QPSK. The I part of the signal is spread using one sequence, while the Q part is spread using a different sequence. The chip time is 16 ...
0 votes
0 answers
323 views
Building a DSSS reciever in GnuRadio
I have some questions regarding building a DSSS receiver in GnuRadio. Specifically with the correlation part. I'm having issues with correlating the m-sequence with the received signal. I have been ...
4 votes
3 answers
305 views
DSP Puzzle - Advanced Signal Forensics - Spread Spectrum PSD
Signal Forensics is the art of detecting likely culprits from the time and frequency spectrum of signals. I made that up, but whatever you want to call it, this is an extremely useful skill, ...
- 58.2k
1 vote
1 answer
177 views
BPSK using carriers other than sinusoidal wave
I am currently a student in communications & electronics engineering undergrad working on a small project employing Direct sequence spread spectrum. For simplicity and since I am using TTL level ...
0 votes
1 answer
588 views
How to measure process gain of DSSS
I have a replicated a Direct sequence spread spectrum link (schematics taken from ARRL SS handbook) and would like to measure performance characteristics such as process gain. I have 2 questions. I ...
2 votes
2 answers
352 views
DSSS spectrum not flat
Why is the PSD of the simulated BPSK/DSSS in AWGN not flat? Here are the simulation parameters: BPSK symbols are randomly generated and are {+1,-1} Spreading factor = 128 Spreading code is a randomly ...
- 567