[USRP-users] QPSK modulation and demodulation
Dear all, I have tried to use the QPAK modulation and demodulation exapmle from the tutorial in the link below. I am using two USRPs B205 as transmitter and receiver, frequency 910MHz , sampling rate 300k or 1 M sps. However, the received signal's constellation after Costas loop are not synchronized (points everywhere in the constellation diagram). Am I missing something i have to change in the usrp setting or synchronization block? https://wiki.gnuradio.org/index.php?title=QPSK_Mod_and_Demod#Phase_and_Frequency_Correction Best regards, Ali siddig ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: QPSK modulation and demodulation
On 28/08/2024 12:13, ali siddig wrote: Dear all, I have tried to use the QPAK modulation and demodulation exapmle from the tutorial in the link below. I am using two USRPs B205 as transmitter and receiver, frequency 910MHz , sampling rate 300k or 1 M sps. However, the received signal's constellation after Costas loop are not synchronized (points everywhere in the constellation diagram). Am I missing something i have to change in the usrp setting or synchronization block? https://wiki.gnuradio.org/index.php?title=QPSK_Mod_and_Demod#Phase_and_Frequency_Correction Best regards, Ali siddig ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com This is more-properly a question for the discuss-gnuradio mailing list, not here. My guess is that you will also require some kind of FLL to track the inevitable frequency differences between TX and RX. But that's just a slightly-educated guess. ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: QPSK modulation and demodulation
I already tried that, but may be it is a parameter values issue I used : Sample per symbol=4 Filter rolloff factor =350m Prototype filter size 44 Loop bandwidth 62.8m When the input value is random source (228,229), it works But when the input value is random source (0,256), it doesn't work Best Regards, On Wed, Aug 28, 2024, 9:02 PM Marcus D. Leech wrote: > On 28/08/2024 12:13, ali siddig wrote: > > Dear all, > > I have tried to use the QPAK modulation and demodulation exapmle from > > the tutorial in the link below. I am using two USRPs B205 as > > transmitter and receiver, frequency 910MHz , sampling rate 300k or 1 M > > sps. However, the received signal's constellation after Costas loop > > are not synchronized (points everywhere in the constellation diagram). > > Am I missing something i have to change in the usrp setting or > > synchronization block? > > > > > https://wiki.gnuradio.org/index.php?title=QPSK_Mod_and_Demod#Phase_and_Frequency_Correction > > > > Best regards, > > Ali siddig > > > > ___ > > USRP-users mailing list -- usrp-users@lists.ettus.com > > To unsubscribe send an email to usrp-users-le...@lists.ettus.com > This is more-properly a question for the discuss-gnuradio mailing list, > not here. > > My guess is that you will also require some kind of FLL to track the > inevitable frequency differences between TX and RX. But >that's just a slightly-educated guess. > > > ___ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-le...@lists.ettus.com > ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: QPSK modulation and demodulation
On 28/08/2024 13:35, ali siddig wrote: I already tried that, but may be it is a parameter values issue I used : Sample per symbol=4 Filter rolloff factor =350m Prototype filter size 44 Loop bandwidth 62.8m When the input value is random source (228,229), it works But when the input value is random source (0,256), it doesn't work Best Regards, And, again, this is more properly a question for the discuss-gnuradio mailing list. The UHD library doesn't provide any DSP functions, per se. So any gnuradio flow-graph questions should be on the discuss-gnuradio mailing list. On Wed, Aug 28, 2024, 9:02 PM Marcus D. Leech wrote: On 28/08/2024 12:13, ali siddig wrote: > Dear all, > I have tried to use the QPAK modulation and demodulation exapmle from > the tutorial in the link below. I am using two USRPs B205 as > transmitter and receiver, frequency 910MHz , sampling rate 300k or 1 M > sps. However, the received signal's constellation after Costas loop > are not synchronized (points everywhere in the constellation diagram). > Am I missing something i have to change in the usrp setting or > synchronization block? > > https://wiki.gnuradio.org/index.php?title=QPSK_Mod_and_Demod#Phase_and_Frequency_Correction > > Best regards, > Ali siddig > > ___ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-le...@lists.ettus.com This is more-properly a question for the discuss-gnuradio mailing list, not here. My guess is that you will also require some kind of FLL to track the inevitable frequency differences between TX and RX. But that's just a slightly-educated guess. ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] X440 Noise Figure
Hello, I have been trying to estimate the Noise Figure of the X440. I looked through all the documentation I could find and couldn't find it anywhere, so I tried to calculate it myself. It looks like the ZU2xDR RFSoC has a NSD of -146dBFS/Hz @ 2.4GHz ( https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Performance-Characteristics) and the Full Scale Input is 1Vppd (0.707Vrms) @ 100ohms ( https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Electrical-Characteristics) . Based on this information I calculate NSD of -139dBm/Hz [-146dBFS/Hz + 10log10(0.707^2/100Ω*1000)], so -139dBm/Hz - -174dBm/Hz gives Noise Figure of 35dB? Add the 1.5 insertion loss of the TCM2-63WX+ on the Daughterboard ( https://files.ettus.com/manual/page_fbx.html), gives an approximate noise figure of the X440 at 36.5dB for 2.4GHz. Is this correct? Seems high, I don't have much experience calculating noise figure from ADC's so I'm wondering if I'm missing something. Thanks, Steve ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: X440 Noise Figure
On 28/08/2024 18:04, Steve Hamn wrote: Hello, I have been trying to estimate the Noise Figure of the X440. I looked through all the documentation I could find and couldn't find it anywhere, so I tried to calculate it myself. It looks like the ZU2xDR RFSoC has a NSD of -146dBFS/Hz @ 2.4GHz (https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Performance-Characteristics) and the Full Scale Input is 1Vppd (0.707Vrms) @ 100ohms (https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Electrical-Characteristics) . Based on this information I calculate NSD of -139dBm/Hz [-146dBFS/Hz + 10log10(0.707^2/100Ω*1000)], so -139dBm/Hz - -174dBm/Hz gives Noise Figure of 35dB? Add the 1.5 insertion loss of the TCM2-63WX+ on the Daughterboard (https://files.ettus.com/manual/page_fbx.html), gives an approximate noise figure of the X440 at 36.5dB for 2.4GHz. Is this correct? Seems high, I don't have much experience calculating noise figure from ADC's so I'm wondering if I'm missing something. Thanks, Steve "Naked" ADCs are inherently very very noisy devices. Since the X440 has no RF pre-processing of any importance, you'd at least need a low-noise filtered front-end to beat the inherent ADC noise into insignificance. For other USRP radios, mostly, that's already taken care of, and the receiver noise-figure is much more "respectable" (not, radio astronomy respectable, but adequate to put onto an over-the-air antenna). ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: X440 Noise Figure
Hi Marcus, Thanks. Understood, that all makes sense to me. Part of this is I'm trying to understand the base Noise Figure as a starting point so I can design my filtered low noise front end as you suggest. I guess you're confirming that 36.5dB is expected from the X440 and there's nothing crazy wrong about my math. Thanks, Steve On Wed, Aug 28, 2024, 3:15 PM Marcus D. Leech wrote: > On 28/08/2024 18:04, Steve Hamn wrote: > > Hello, > > > > I have been trying to estimate the Noise Figure of the X440. I looked > > through all the documentation I could find and couldn't find it > > anywhere, so I tried to calculate it myself. > > > > It looks like the ZU2xDR RFSoC has a NSD of -146dBFS/Hz @ 2.4GHz > > ( > https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Performance-Characteristics) > > > and the Full Scale Input is 1Vppd (0.707Vrms) @ 100ohms > > ( > https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Electrical-Characteristics) > > > . > > > > Based on this information I calculate NSD of -139dBm/Hz [-146dBFS/Hz + > > 10log10(0.707^2/100Ω*1000)], so -139dBm/Hz - -174dBm/Hz gives Noise > > Figure of 35dB? Add the 1.5 insertion loss of the TCM2-63WX+ on the > > Daughterboard (https://files.ettus.com/manual/page_fbx.html), gives an > > approximate noise figure of the X440 at 36.5dB for 2.4GHz. > > > > Is this correct? Seems high, I don't have much experience calculating > > noise figure from ADC's so I'm wondering if I'm missing something. > > > > Thanks, > > > > Steve > > > > > "Naked" ADCs are inherently very very noisy devices. Since the X440 has > no RF pre-processing of any importance, you'd at >least need a low-noise filtered front-end to beat the inherent ADC > noise into insignificance.For other USRP radios, mostly, >that's already taken care of, and the receiver noise-figure is much > more "respectable" (not, radio astronomy respectable, >but adequate to put onto an over-the-air antenna). > > > ___ > USRP-users mailing list -- usrp-users@lists.ettus.com > To unsubscribe send an email to usrp-users-le...@lists.ettus.com > ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: X440 Noise Figure
On 28/08/2024 18:36, Steve Hamn wrote: Hi Marcus, Thanks. Understood, that all makes sense to me. Part of this is I'm trying to understand the base Noise Figure as a starting point so I can design my filtered low noise front end as you suggest. I guess you're confirming that 36.5dB is expected from the X440 and there's nothing crazy wrong about my math. Might be a *bit* high, but like I said, ADCs have notoriously-high equivalent noise figure. I don't think anyone at NI/Emerson has done a "hard characterization" of the equivalent noise figure, because, well, it's always going to be "somewhere around horrific". Nobody would likely expect to connect this directly to an antenna (except maybe on HF) and expect good results... Thanks, Steve On Wed, Aug 28, 2024, 3:15 PM Marcus D. Leech wrote: On 28/08/2024 18:04, Steve Hamn wrote: > Hello, > > I have been trying to estimate the Noise Figure of the X440. I looked > through all the documentation I could find and couldn't find it > anywhere, so I tried to calculate it myself. > > It looks like the ZU2xDR RFSoC has a NSD of -146dBFS/Hz @ 2.4GHz > (https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Performance-Characteristics) > and the Full Scale Input is 1Vppd (0.707Vrms) @ 100ohms > (https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Electrical-Characteristics) > . > > Based on this information I calculate NSD of -139dBm/Hz [-146dBFS/Hz + > 10log10(0.707^2/100Ω*1000)], so -139dBm/Hz - -174dBm/Hz gives Noise > Figure of 35dB? Add the 1.5 insertion loss of the TCM2-63WX+ on the > Daughterboard (https://files.ettus.com/manual/page_fbx.html), gives an > approximate noise figure of the X440 at 36.5dB for 2.4GHz. > > Is this correct? Seems high, I don't have much experience calculating > noise figure from ADC's so I'm wondering if I'm missing something. > > Thanks, > > Steve > > "Naked" ADCs are inherently very very noisy devices. Since the X440 has no RF pre-processing of any importance, you'd at least need a low-noise filtered front-end to beat the inherent ADC noise into insignificance. For other USRP radios, mostly, that's already taken care of, and the receiver noise-figure is much more "respectable" (not, radio astronomy respectable, but adequate to put onto an over-the-air antenna). ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com ___ USRP-users mailing list -- usrp-users@lists.ettus.com To unsubscribe send an email to usrp-users-le...@lists.ettus.com
[USRP-users] Re: X440 Noise Figure
Here's an article that may help with your NF calculations.
"Calculating noise figure and third-order intercept in ADCs"
https://www.ti.com/lit/an/slyt090/slyt090.pdf
I wrote a little C program from it.
#include
#include
#include
int main(int argc, char **argv)
{
double k, t, dBm1Hz, dBm500Hz;
double vpp, p, sinad, rate, VdBm, dBHz, dBmHz;
if (argc != 4) {
fprintf(stderr, "usage: bdr rate>\n");
exit(-1);
}
vpp = atof(argv[1]);
sinad = atof(argv[2]);
rate = atof(argv[3]);
k = 1.38064852e-23;
t = 290.0;
p = k * t * 1 * 1000.0;
dBm1Hz = 10.0 * log10(p);
p = k * t * 500 * 1000.0;
dBm500Hz = 10.0 * log10(p);
p = (vpp * vpp) / (50 * 8);
VdBm = (10.0 * log10(p)) + 30;
dBHz = 10.0 * log10(rate / 2);
dBmHz = (VdBm - 1) - sinad - dBHz;
printf("overload = %.2f dBm\n", VdBm);
printf("Noise Figure = %.2f dB, %.2f dBm/Hz\n", dBmHz - dBm1Hz, dBmHz);
printf("MDS in 500 Hz bandwidth = %.2f dBm\n", dBm500Hz + (dBmHz -
dBm1Hz));
printf("500 Hz Dynamic Range = %.2f dB\n", VdBm - (dBm500Hz +
(dBmHz - dBm1Hz)));
return 0;
}
Ron
On 8/28/24 15:36, Steve Hamn wrote:
Hi Marcus,
Thanks. Understood, that all makes sense to me. Part of this is I'm
trying to understand the base Noise Figure as a starting point so I
can design my filtered low noise front end as you suggest.
I guess you're confirming that 36.5dB is expected from the X440 and
there's nothing crazy wrong about my math.
Thanks,
Steve
On Wed, Aug 28, 2024, 3:15 PM Marcus D. Leech
wrote:
On 28/08/2024 18:04, Steve Hamn wrote:
> Hello,
>
> I have been trying to estimate the Noise Figure of the X440. I
looked
> through all the documentation I could find and couldn't find it
> anywhere, so I tried to calculate it myself.
>
> It looks like the ZU2xDR RFSoC has a NSD of -146dBFS/Hz @ 2.4GHz
>
(https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Performance-Characteristics)
> and the Full Scale Input is 1Vppd (0.707Vrms) @ 100ohms
>
(https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Electrical-Characteristics)
> .
>
> Based on this information I calculate NSD of -139dBm/Hz
[-146dBFS/Hz +
> 10log10(0.707^2/100Ω*1000)], so -139dBm/Hz - -174dBm/Hz gives Noise
> Figure of 35dB? Add the 1.5 insertion loss of the TCM2-63WX+ on the
> Daughterboard (https://files.ettus.com/manual/page_fbx.html),
gives an
> approximate noise figure of the X440 at 36.5dB for 2.4GHz.
>
> Is this correct? Seems high, I don't have much experience
calculating
> noise figure from ADC's so I'm wondering if I'm missing something.
>
> Thanks,
>
> Steve
>
>
"Naked" ADCs are inherently very very noisy devices. Since the
X440 has
no RF pre-processing of any importance, you'd at
least need a low-noise filtered front-end to beat the inherent ADC
noise into insignificance. For other USRP radios, mostly,
that's already taken care of, and the receiver noise-figure is
much
more "respectable" (not, radio astronomy respectable,
but adequate to put onto an over-the-air antenna).
___
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[USRP-users] Re: X440 Noise Figure
On 28/08/2024 19:36, Ron Economos via USRP-users wrote:
Here's an article that may help with your NF calculations.
"Calculating noise figure and third-order intercept in ADCs"
https://www.ti.com/lit/an/slyt090/slyt090.pdf
I wrote a little C program from it.
#include
#include
#include
int main(int argc, char **argv)
{
double k, t, dBm1Hz, dBm500Hz;
double vpp, p, sinad, rate, VdBm, dBHz, dBmHz;
if (argc != 4) {
fprintf(stderr, "usage: bdr rate>\n");
exit(-1);
}
vpp = atof(argv[1]);
sinad = atof(argv[2]);
rate = atof(argv[3]);
k = 1.38064852e-23;
t = 290.0;
p = k * t * 1 * 1000.0;
dBm1Hz = 10.0 * log10(p);
p = k * t * 500 * 1000.0;
dBm500Hz = 10.0 * log10(p);
p = (vpp * vpp) / (50 * 8);
VdBm = (10.0 * log10(p)) + 30;
dBHz = 10.0 * log10(rate / 2);
dBmHz = (VdBm - 1) - sinad - dBHz;
printf("overload = %.2f dBm\n", VdBm);
printf("Noise Figure = %.2f dB, %.2f dBm/Hz\n", dBmHz - dBm1Hz,
dBmHz);
printf("MDS in 500 Hz bandwidth = %.2f dBm\n", dBm500Hz + (dBmHz -
dBm1Hz));
printf("500 Hz Dynamic Range = %.2f dB\n", VdBm - (dBm500Hz +
(dBmHz - dBm1Hz)));
return 0;
}
Ron
Before getopt(), before dinosaurs, there was raw processing of argv[],
like a boss :) :)
You and I must be of a similar era :)
Actually, I learned C before even existed. That was a "modern
luxury" when I started using it :)
On 8/28/24 15:36, Steve Hamn wrote:
Hi Marcus,
Thanks. Understood, that all makes sense to me. Part of this is I'm
trying to understand the base Noise Figure as a starting point so I
can design my filtered low noise front end as you suggest.
I guess you're confirming that 36.5dB is expected from the X440 and
there's nothing crazy wrong about my math.
Thanks,
Steve
On Wed, Aug 28, 2024, 3:15 PM Marcus D. Leech
wrote:
On 28/08/2024 18:04, Steve Hamn wrote:
> Hello,
>
> I have been trying to estimate the Noise Figure of the X440. I
looked
> through all the documentation I could find and couldn't find it
> anywhere, so I tried to calculate it myself.
>
> It looks like the ZU2xDR RFSoC has a NSD of -146dBFS/Hz @ 2.4GHz
>
(https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Performance-Characteristics)
> and the Full Scale Input is 1Vppd (0.707Vrms) @ 100ohms
>
(https://docs.amd.com/r/en-US/ds926-zynq-ultrascale-plus-rfsoc/RF-ADC-Electrical-Characteristics)
> .
>
> Based on this information I calculate NSD of -139dBm/Hz
[-146dBFS/Hz +
> 10log10(0.707^2/100Ω*1000)], so -139dBm/Hz - -174dBm/Hz gives
Noise
> Figure of 35dB? Add the 1.5 insertion loss of the TCM2-63WX+ on
the
> Daughterboard (https://files.ettus.com/manual/page_fbx.html),
gives an
> approximate noise figure of the X440 at 36.5dB for 2.4GHz.
>
> Is this correct? Seems high, I don't have much experience
calculating
> noise figure from ADC's so I'm wondering if I'm missing something.
>
> Thanks,
>
> Steve
>
>
"Naked" ADCs are inherently very very noisy devices. Since the
X440 has
no RF pre-processing of any importance, you'd at
least need a low-noise filtered front-end to beat the inherent
ADC
noise into insignificance. For other USRP radios, mostly,
that's already taken care of, and the receiver noise-figure is
much
more "respectable" (not, radio astronomy respectable,
but adequate to put onto an over-the-air antenna).
___
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