On 06/05/2023 16:40, Marcus Müller wrote:
Yep, that'd be rate-1; you don't need to squint much to see that the
N-point-DFT has exactly N (=often 2ᵐ) such entries, and when you send N
symbols in parallel, you get a DSSS-single-user-CDMA system called OFDM :D
But that's not on bit-level.
Hi Ma
Hi Daniel,
On 03/05/2023 18:20, Marcus Müller wrote:
¹ this is the standard situation for me to start a flamewar on the nature of DSSS: from a coding perspective, DSSS is just a repetition code. Repetition codes are what we call "bad", so instead of concatenating a r = 1/F DSSS-repetition-code
On 03/05/2023 18:20, Marcus Müller wrote:
¹ this is the standard situation for me to start a flamewar on the
nature of DSSS: from a coding perspective, DSSS is just a repetition
code. Repetition codes are what we call "bad", so instead of
concatenating a r = 1/F DSSS-repetition-code after a r=
> Tough I can foresee objections from narrow-band users of
> QO100 :)
Those should be on the narrowband transceiver on a slightly different band!
Cheers,
Marcus
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Hi,
I have already make a proposal that with fh=False a multi user CDMA can be
used.Each user will have a unique time in sawtooth shifting, the same time he
can see all other Tx signals.Each Tx will be seen as 'constant frequency' as
all users shift frequency the same rate.I do not claim that i
Hi Marcus,
In QO100 there are Doppler shifts (that is the reason of the 200 Hz shift in
flowchart).I have already implement a flowchart of calculating it using the
middle BPSK beacon of QO100 using the frequency error of costal loop.My ground
station is equipped with GPSDO.I have already do sp
Sorry,, I meant to send the previous email to the list.
On Thursday, 4 May 2023 13:01:10 EEST Marcus Müller wrote:
> Because you intuitively would start with a single symbol and multiply it
> with the *whole* sequence. What George's code does is different: It takes
> each sample of the audio sign
Hey,
On 04.05.23 11:38, Adrian Musceac wrote:
On Thursday, 4 May 2023 12:11:47 EEST you wrote:
Hi Adrian,
for CDMA, two things need to be different:
1. you need at least one orthogonal other sequence used by another user /
data stream – that MA in CDMA is multiple access :)
I was assuming m
Hi Adrian,
for CDMA, two things need to be different:
1. you need at least one orthogonal other sequence used by another user / data stream –
that MA in CDMA is multiple access :)
2. In classical CDMA, you would need your data to be a constant that you multiply with
your sequences – if you mu
On Wednesday, 3 May 2023 19:20:10 EEST Marcus Müller wrote:
> Hi George,
>
> that's a multiplicative voice scrambler!
>
> The pre-Second World war voice scrambler system "SIGSALY" [1] was kind
> of similar;
> just that the scrambling sequence came out of a noisy vacuum tube, not
> Python's random
Hi George,
that's a multiplicative voice scrambler!
The pre-Second World war voice scrambler system "SIGSALY" [1] was kind
of similar;
just that the scrambling sequence came out of a noisy vacuum tube, not
Python's random.random(), and that the combination method was taking
samples and adding
Hi Marcus,
Thanks for your detailed answer!!!Can we consider this approach as a new spread
spectrum technology or is really an existing one?
Best regards
George SV1BDS
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Στις Δευ, 1 Μαΐ, 2023 στις 23:14, ο χρήστηςMarcus
Müller έγραψε: Hi George,
Hi George,
thanks for the reply!
"VCO generator":
It produces two different vectors depending of fh Boolean value. A sawtooth
vector of
values between -0.5 and 0.5 or the same random values between -0.5 and
0.5. The
sawtooth values used in alignment phase (adjusting myblock
Hi Marcus ,
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Στις Σάβ, 29 Απρ, 2023 στις 14:23, ο χρήστηςMarcus
Müller έγραψε: Hi George,
that flow graph doesn't frequency-hop :) It does something different,
rather cool. Please correct me if I got anything wrong about your
self-written bloc
Hi George,
that flow graph doesn't frequency-hop :) It does something different,
rather cool. Please correct me if I got anything wrong about your
self-written blocks below:
What you do is:
"VCO generator":
Produces always the same 10240-long vector with pseudo-random values,
"Repeat":
R
Hi,
Thanks for the answers.I attach the Rx flowchart and grc of the frequency
hopping. I have successfully used it on QO100 satellite.
George SV1BDS
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Στις Πέμ, 27 Απρ, 2023 στις 14:57, ο χρήστηςMarcus
Müller έγραψε: Hi George,
> Also I have i
Hi George,
> Also I have implemented 1.000.000 hops/sec frequency hopping at QO100
satellite, spread
> over 1 MHz, using 10240 different frequencies.
> Is this project of general interest?
Well, that's impossible to say, but honestly: it probably is! And also, you shouldn't care
too much :) It
Hello,
I create this script using Python to create QAM constellations points.May be of
general interest.
# constellation creation script by George SV1BDSn = 7 # 3 for 16QAM, 7 for
64QAM, 15 for 256QAM, 31 for 1024QAM, 63 for 4096QAMc = '['for i in
range(-n,n+2,2): for j in range(-n,n+2,2): c
Hi Michel,
welcome to the mailing list.
I must admit that I don't really know what you want to do.
Can you explain it, so that doesn't know what a DMR-C4FM relay is,
understands?
I think you're referring to some GRC flow graphs, but sadly we don't
know which ones you have been looking at. So, s
Hello all!
I designed in 2018 the DMR-C4FM relay from Albi (Tarn), F5ZLH
it works…
Well, not that good, because we noticed a poor signal quality:
with the constellation, on a portable equipment such as the Rpi 4. we
will beable to adjust the relay settings
And there only GNURadio is installed
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