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Today's Topics:
1. USRP B100 Tuning Issue (Mark McCarron)
2. Re: USRP B100 Tuning Issue (Ian Buckley)
3. Re: USRP B100 Tuning Issue (Mark McCarron)
4. Re: USRP B100 Tuning Issue (Ian Buckley)
5. Re: USRP B100 Tuning Issue (Marcus D. Leech)
6. Re: USRP B100 Tuning Issue (John Malsbury)
7. Re: USRP B100 Tuning Issue (Mark McCarron)
8. Re: USRP B100 Tuning Issue (Marcus D. Leech)
9. Re: USRP B100 Tuning Issue (Mark McCarron)
10. Re: USRP B100 Tuning Issue (Marcus D. Leech)
11. Re: USRP B100 Tuning Issue (Mark McCarron)
12. UHD driver for Matlab R2012b (Raja Sattiraju)
13. Document about the FPGA (Gong Zhang)
14. Re: UHD driver for Matlab R2012b (Mike McLernon)
----------------------------------------------------------------------
Message: 1
Date: Tue, 7 May 2013 22:03:03 +0100
From: Mark McCarron <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
I received a USRP B100 today and I am experiencing some
issues with the Basic Rx. I am getting the following warning from
GNURadio:
UHD Warning:
The hardware does not support the requested RX frequency:
Target frequency: 98.300000 MHz
Actual frequency: -29.700000 MHz
I
have also tested this using ExtIO_USRP and I notice that any requests
to change the LO result in the hardware changing the frequency between
-32MHz and +32MHz. This is the output:
Req: 160.470884 MHz
H/W: -31.529116 MHz
Target LO: 160.470884 MHz
Actual LO: 0.000000 Hz
Target DDC: -160.470884 MHz
Actual DDC: 31.529116 MHz
Req: 240.470884 MHz
H/W: -15.529116 MHz
Target LO: 240.470884 MHz
Actual LO: 0.000000 Hz
Target DDC: -240.470884 MHz
Actual DDC: 15.529116 MHz
Req: 140.470884 MHz
H/W: 12.470884 MHz
Target LO: 140.470884 MHz
Actual LO: 0.000000 Hz
Target DDC: -140.470884 MHz
Actual DDC: -12.470884 MHz
This results in the same portion of 64MHz of spectrum looping during tuning.
Is the driver broken???
Regards,
Mark McCarron
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Message: 2
Date: Tue, 7 May 2013 14:22:22 -0700
From: Ian Buckley <[email protected]>
To: Mark McCarron <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Mark,
The B100 runs at a 64MHz sampling rate. Basic RX has no LO, it's really just
simple amplifiers to buffer the antenna connections and no filtering.
Thus the only available tuning elements are the DUC/DDC in the FPGA, and there
tuning range is naturally bounded by the sample rate.
You can target the frequencies in your example because the bandwidth of basicRX
is so high, but you must supply external filtering to prevent other frequency
ranges aliasing onto them.
-Ian
On May 7, 2013, at 2:03 PM, Mark McCarron <[email protected]> wrote:
> I received a USRP B100 today and I am experiencing some issues with the
> Basic Rx. I am getting the following warning from GNURadio:
>
> UHD Warning:
> The hardware does not support the requested RX frequency:
> Target frequency: 98.300000 MHz
> Actual frequency: -29.700000 MHz
>
> I have also tested this using ExtIO_USRP and I notice that any requests to
> change the LO result in the hardware changing the frequency between -32MHz
> and +32MHz. This is the output:
>
> Req: 160.470884 MHz
> H/W: -31.529116 MHz
> Target LO: 160.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -160.470884 MHz
> Actual DDC: 31.529116 MHz
>
>
> Req: 240.470884 MHz
> H/W: -15.529116 MHz
> Target LO: 240.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -240.470884 MHz
> Actual DDC: 15.529116 MHz
>
> Req: 140.470884 MHz
> H/W: 12.470884 MHz
> Target LO: 140.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -140.470884 MHz
> Actual DDC: -12.470884 MHz
>
> This results in the same portion of 64MHz of spectrum looping during tuning.
> Is the driver broken???
>
> Regards,
>
> Mark McCarron
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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Message: 3
Date: Tue, 7 May 2013 22:43:17 +0100
From: Mark McCarron <[email protected]>
To: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Ian,
Thanks for that, this is something Ettus Research fails to make clear on their
website. So, what filtering options exist and where can I find them?
Regards,
Mark McCarron
Subject: Re: [USRP-users] USRP B100 Tuning Issue
From: [email protected]
Date: Tue, 7 May 2013 14:22:22 -0700
CC: [email protected]
To: [email protected]
Mark, The B100 runs at a 64MHz sampling rate. Basic RX has no LO, it's really
just simple amplifiers to buffer the antenna connections and no filtering.Thus
the only available tuning elements are the DUC/DDC in the FPGA, and there
tuning range is naturally bounded by the sample rate.You can target the
frequencies in your example because the bandwidth of basicRX is so high, but
you must supply external filtering to prevent other frequency ranges aliasing
onto them.-Ian
On May 7, 2013, at 2:03 PM, Mark McCarron <[email protected]> wrote:I
received a USRP B100 today and I am experiencing some issues with the Basic
Rx. I am getting the following warning from GNURadio:
UHD Warning:
The hardware does not support the requested RX frequency:
Target frequency: 98.300000 MHz
Actual frequency: -29.700000 MHz
I have also tested this using ExtIO_USRP and I notice that any requests to
change the LO result in the hardware changing the frequency between -32MHz and
+32MHz. This is the output:
Req: 160.470884 MHz
H/W: -31.529116 MHz
Target LO: 160.470884 MHz
Actual LO: 0.000000 Hz
Target DDC: -160.470884 MHz
Actual DDC: 31.529116 MHz
Req: 240.470884 MHz
H/W: -15.529116 MHz
Target LO: 240.470884 MHz
Actual LO: 0.000000 Hz
Target DDC: -240.470884 MHz
Actual DDC: 15.529116 MHz
Req: 140.470884 MHz
H/W: 12.470884 MHz
Target LO: 140.470884 MHz
Actual LO: 0.000000 Hz
Target DDC: -140.470884 MHz
Actual DDC: -12.470884 MHz
This results in the same portion of 64MHz of spectrum looping during tuning.
Is the driver broken???
Regards,
Mark McCarron_______________________________________________
USRP-users mailing list
[email protected]
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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Message: 4
Date: Tue, 7 May 2013 15:41:43 -0700
From: Ian Buckley <[email protected]>
To: Mark McCarron <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Mark,
Actually my minor error, its LFRX that has amp's, Basic-RX uses only
transformers.
The BasicRX is accurately described here:
https://www.ettus.com/product/details/BasicRX
My first point of call for filters, LNA's etc is generally Mini-Circuits. Of
course if you are handy with electronics you can knock up simple filters for
very little cost.
Out of interest what is your application/frequency of interest? Perhaps we can
make a more focused suggestion for you?
-Ian
On May 7, 2013, at 2:43 PM, Mark McCarron <[email protected]> wrote:
> Ian,
>
> Thanks for that, this is something Ettus Research fails to make clear on
> their website. So, what filtering options exist and where can I find them?
>
> Regards,
>
> Mark McCarron
>
> Subject: Re: [USRP-users] USRP B100 Tuning Issue
> From: [email protected]
> Date: Tue, 7 May 2013 14:22:22 -0700
> CC: [email protected]
> To: [email protected]
>
> Mark,
> The B100 runs at a 64MHz sampling rate. Basic RX has no LO, it's really just
> simple amplifiers to buffer the antenna connections and no filtering.
> Thus the only available tuning elements are the DUC/DDC in the FPGA, and
> there tuning range is naturally bounded by the sample rate.
> You can target the frequencies in your example because the bandwidth of
> basicRX is so high, but you must supply external filtering to prevent other
> frequency ranges aliasing onto them.
> -Ian
>
> On May 7, 2013, at 2:03 PM, Mark McCarron <[email protected]> wrote:
>
> I received a USRP B100 today and I am experiencing some issues with the
> Basic Rx. I am getting the following warning from GNURadio:
>
> UHD Warning:
> The hardware does not support the requested RX frequency:
> Target frequency: 98.300000 MHz
> Actual frequency: -29.700000 MHz
>
> I have also tested this using ExtIO_USRP and I notice that any requests to
> change the LO result in the hardware changing the frequency between -32MHz
> and +32MHz. This is the output:
>
> Req: 160.470884 MHz
> H/W: -31.529116 MHz
> Target LO: 160.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -160.470884 MHz
> Actual DDC: 31.529116 MHz
>
>
> Req: 240.470884 MHz
> H/W: -15.529116 MHz
> Target LO: 240.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -240.470884 MHz
> Actual DDC: 15.529116 MHz
>
> Req: 140.470884 MHz
> H/W: 12.470884 MHz
> Target LO: 140.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -140.470884 MHz
> Actual DDC: -12.470884 MHz
>
> This results in the same portion of 64MHz of spectrum looping during tuning.
> Is the driver broken???
>
> Regards,
>
> Mark McCarron
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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Message: 5
Date: Tue, 07 May 2013 19:20:15 -0400
From: "Marcus D. Leech" <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
On 05/07/2013 05:43 PM, Mark McCarron wrote:
> Ian,
>
> Thanks for that, this is something Ettus Research fails to make clear
> on their website. So, what filtering options exist and where can I
> find them?
>
> Regards,
>
> Mark McCarron
You aren't the first person to be somewhat confused about the
capabilities of the BASIC_RX series cards, all I can say is that I know
that the data-sheets
are currently being worked over, feverishly, to clarify things like
that, and provide more detailed characterization across all of the various
daughtercards.
There are filter manufacturers all over the place, and for frequencies
below 200Mhz or so, you can build your own from discrete L-C components,
without too much hassle. I've often used this website to help me
design filters from parts I happened to have lying around:
http://www.wa4dsy.net/filter/filterdesign.html
The thing to understand about these BASIC_RX cards is that they're just
designed for direct-sampling into the ADCs. The analog bits of the card
itself are
good to about 250MHz before they start to attenuate, and the ADCs are
also good to fairly high frequencies, which means that so-called
bandpass-sampling can be achieved:
http://en.wikipedia.org/wiki/Undersampling
So, any signals that are presented to the card above the 1st Nyquist
zone (32Mhz for USRP1/B100/E1XX, 50Mhz for N2XX) get *aliased* to
other frequencies that are within the 1st Nyquist zone. The UHD
drivers know this, and will set the tuning (which is all-digital in the case
of the BASIC_RX) based on alias calculations. But in order to make
this work, you have to have bandpass filters of reasonably high-order
to limit the frequencies presented to the ADCs to the "Nyquist Zone"
of interest. Otherwise the "real" frequencies and "alias" frequencies
will both be presented to the ADC, which will cause nothing but grief.
For example, if you wanted to use BASIC_RX just for listening to the
broadcast FM band, you would provide a bit of gain, and a filter that
stiffly presents only the 88-to-108Mhz chunk of spectrum to the
BASIC_RX. Notice that the bandwidth of this--20Mhz, is less than the
1st-Nyquist bandwidth of the USRP1/B100 (32Mhz), so that will work
reasonably well. In fact, it turns out that good-quality FM-band
filters are cheaply available, such as these:
http://radiohobbystore.com/gfwb3.html
Similar strategies can be used to do bandpass sampling at other
frequencies, but once you have a biggish filter-bank setup, you might
consider
a card with actual on-board analog downconversion like WBX or TVRX2, etc.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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Message: 6
Date: Tue, 7 May 2013 16:22:15 -0700
From: John Malsbury <[email protected]>
To: Mark McCarron <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID:
<can5wegqzpg+uqobf+mawypm2hzkwscuo6+mr0ob2fms_3xi...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Mark,
Thank you for the feedback. We've updated the product page, which
correctly stated that the input signals were transformer coupled. The new
text makes things a bit more clear.
-John
On Tue, May 7, 2013 at 2:43 PM, Mark McCarron <[email protected]>wrote:
> Ian,
>
> Thanks for that, this is something Ettus Research fails to make clear on
> their website. So, what filtering options exist and where can I find them?
>
> Regards,
>
> Mark McCarron
>
> ------------------------------
> Subject: Re: [USRP-users] USRP B100 Tuning Issue
> From: [email protected]
> Date: Tue, 7 May 2013 14:22:22 -0700
> CC: [email protected]
> To: [email protected]
>
>
> Mark,
> The B100 runs at a 64MHz sampling rate. Basic RX has no LO, it's really
> just simple amplifiers to buffer the antenna connections and no filtering.
> Thus the only available tuning elements are the DUC/DDC in the FPGA, and
> there tuning range is naturally bounded by the sample rate.
> You can target the frequencies in your example because the bandwidth of
> basicRX is so high, but you must supply external filtering to prevent other
> frequency ranges aliasing onto them.
> -Ian
>
> On May 7, 2013, at 2:03 PM, Mark McCarron <[email protected]>
> wrote:
>
> I received a USRP B100 today and I am experiencing some issues with the
> Basic Rx. I am getting the following warning from GNURadio:
>
> UHD Warning:
> The hardware does not support the requested RX frequency:
> Target frequency: 98.300000 MHz
> Actual frequency: -29.700000 MHz
>
> I have also tested this using ExtIO_USRP and I notice that any requests to
> change the LO result in the hardware changing the frequency between -32MHz
> and +32MHz. This is the output:
>
> Req: 160.470884 MHz
> H/W: -31.529116 MHz
> Target LO: 160.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -160.470884 MHz
> Actual DDC: 31.529116 MHz
>
>
> Req: 240.470884 MHz
> H/W: -15.529116 MHz
> Target LO: 240.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -240.470884 MHz
> Actual DDC: 15.529116 MHz
>
> Req: 140.470884 MHz
> H/W: 12.470884 MHz
> Target LO: 140.470884 MHz
> Actual LO: 0.000000 Hz
> Target DDC: -140.470884 MHz
> Actual DDC: -12.470884 MHz
>
> This results in the same portion of 64MHz of spectrum looping during
> tuning. Is the driver broken???
>
> Regards,
>
> Mark McCarron
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
>
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
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Message: 7
Date: Wed, 8 May 2013 01:54:55 +0100
From: Mark McCarron <[email protected]>
To: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Marcus,
That was an excellent explanation. You should write the user manuals. :)
Is there a complete filter bank that spans 1-250MHz that can be interfaced
either through USB or the B100?
I had been reading other posts of yours because I am trying to create a proper
antenna setup. I see that the Basic Rx/Tx have different input specs from the
WBX. 2Vpp and 0.2Vpp respectively. I didn't see any specs on the maximum
input current.
So far, I have come up with this basic list:
Basic Tx
Wideband Tx Antenna (either 1-250MHz or to the bottom end of the WBX @50MHz)
5000A/8000A wideband lightening/surge protector (low insertion loss @0.2dB or
better)
RF Wideband Power Amp to match antenna
Low pass filter - cutoff 250MHz
Basic Rx
Wideband Rx Antenna (either 1-250MHz or to the bottom end of the WBX @50MHz,
possibly Active Antenna)
5000A/8000A wideband lightening/surge protector (low insertion loss @0.2dB or
better)
Wideband LNA to match antenna (or use active antenna)
Low pass filter - cutoff 250MHz
WBX (Tx)
Wideband Tx Antenna (either 50-2200MHz or to the top end of the Basic Tx
@250MHz)
5000A/8000A wideband lightening/surge protector (low insertion loss @0.2dB or
better)
RF Wideband Power Amp to match antenna
Low pass filter - cutoff 2.2GHz
WBX (Rx)
Wideband Rx Antenna (either 50-2200MHz or to the top end of the Basic Rx
@250MHz, possibly Active Antenna)
5000A/8000A wideband lightening/surge protector (low insertion loss @0.2dB or
better)
Wideband LNA to match antenna (or use active antenna)
Low pass filter - cutoff 2.2GHz
To prevent transient pulses from damaging the B100 that are not enough to
trigger the surge protector (I think these kick in at 90Vpp), I require
something that will attenuate input signals. I think you recommended -25dBm
for the WBX. I didn't see a recommendation for the Basic Tx/Rx. Any good
suggestions?
Do you see any problems or anything I have missed?
Regards,
Mark McCarron
Date: Tue, 7 May 2013 19:20:15 -0400
From: [email protected]
To: [email protected]
Subject: Re: [USRP-users] USRP B100 Tuning Issue
On 05/07/2013 05:43 PM, Mark McCarron wrote:
Ian,
Thanks for that, this is something Ettus Research fails to make
clear on their website. So, what filtering options exist and
where can I find them?
Regards,
Mark McCarron
You aren't the first person to be somewhat confused about the
capabilities of the BASIC_RX series cards, all I can say is that I
know that the data-sheets
are currently being worked over, feverishly, to clarify things
like that, and provide more detailed characterization across all of
the various
daughtercards.
There are filter manufacturers all over the place, and for
frequencies below 200Mhz or so, you can build your own from discrete
L-C components,
without too much hassle. I've often used this website to help me
design filters from parts I happened to have lying around:
http://www.wa4dsy.net/filter/filterdesign.html
The thing to understand about these BASIC_RX cards is that they're
just designed for direct-sampling into the ADCs. The analog bits of
the card itself are
good to about 250MHz before they start to attenuate, and the ADCs
are also good to fairly high frequencies, which means that so-called
bandpass-sampling can be achieved:
http://en.wikipedia.org/wiki/Undersampling
So, any signals that are presented to the card above the 1st Nyquist
zone (32Mhz for USRP1/B100/E1XX, 50Mhz for N2XX) get *aliased* to
other frequencies that are within the 1st Nyquist zone. The UHD
drivers know this, and will set the tuning (which is all-digital in
the case
of the BASIC_RX) based on alias calculations. But in order to
make this work, you have to have bandpass filters of reasonably
high-order
to limit the frequencies presented to the ADCs to the "Nyquist
Zone" of interest. Otherwise the "real" frequencies and "alias"
frequencies
will both be presented to the ADC, which will cause nothing but
grief.
For example, if you wanted to use BASIC_RX just for listening to the
broadcast FM band, you would provide a bit of gain, and a filter
that
stiffly presents only the 88-to-108Mhz chunk of spectrum to the
BASIC_RX. Notice that the bandwidth of this--20Mhz, is less than
the
1st-Nyquist bandwidth of the USRP1/B100 (32Mhz), so that will work
reasonably well. In fact, it turns out that good-quality FM-band
filters are cheaply available, such as these:
http://radiohobbystore.com/gfwb3.html
Similar strategies can be used to do bandpass sampling at other
frequencies, but once you have a biggish filter-bank setup, you
might consider
a card with actual on-board analog downconversion like WBX or
TVRX2, etc.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
_______________________________________________
USRP-users mailing list
[email protected]
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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Message: 8
Date: Tue, 07 May 2013 21:19:48 -0400
From: "Marcus D. Leech" <[email protected]>
To: Mark McCarron <[email protected]>,
"[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
On 05/07/2013 08:54 PM, Mark McCarron wrote:
> Marcus,
>
> That was an excellent explanation. You should write the user manuals. :)
>
> Is there a complete filter bank that spans 1-250MHz that can be
> interfaced either through USB or the B100?
Not that I'm aware of. Such "filter banks" usually aren't done as a
separate commercial module, but usually integrated into the
front-end of some types of receivers.
>
> I had been reading other posts of yours because I am trying to create
> a proper antenna setup. I see that the Basic Rx/Tx have different
> input specs from the WBX. 2Vpp and 0.2Vpp respectively. I didn't see
> any specs on the maximum input current.
Well, the input impedance is 50 ohms, so ohms law. The WBX is a full
analog downconverter with a complete RF gain chain, mixers, etc. It's
more along the lines of what you'd expect for a
wants-to-be-plugged-into-an-antenna receiver for 50Mhz to 2.2GHz, so the
maximum input levels
are very much lower, as you would expect. Generally in RF, we refer
everything to dBm, usually in a 50Ohm system, rather than talking about
P-P voltage levels. That's just the way the RF industry "works".
>
> So far, I have come up with this basic list:
>
> Basic Tx
> Wideband Tx Antenna (either 1-250MHz or to the bottom end of the WBX
> @50MHz)
> 5000A/8000A wideband lightening/surge protector (low insertion loss
> @0.2dB or better)
> RF Wideband Power Amp to match antenna
> Low pass filter - cutoff 250MHz
I'd again urge caution in the use of RF power amps at arbitrary
frequencies. That's likely to get unwanted attention not only from
law enforcement, but other properly-licensed users of the same spectrum.
>
> Basic Rx
> Wideband Rx Antenna (either 1-250MHz or to the bottom end of the WBX
> @50MHz, possibly Active Antenna)
> 5000A/8000A wideband lightening/surge protector (low insertion loss
> @0.2dB or better)
> Wideband LNA to match antenna (or use active antenna)
> Low pass filter - cutoff 250MHz
For terrestrial applications below 50Mhz or so, there's no point in
trying to even *design* a *true* low-noise amplifier.
Terrestrial and background galactic noise will utterly dominate any
noise added by the electronics themselves.
Also, below about 1GHz, it's hard to find low-noise amplifiers with
enough dynamic range (expressed as p1dB and OIP3)
that you can do without application-specific filtering. The RF
spectrum is *really crowded* these days, and strong signals
are everywhere that can easily drive your nice little LNA into
non-linear territory without app-specific filtering.
>
> WBX (Tx)
> Wideband Tx Antenna (either 50-2200MHz or to the top end of the Basic
> Tx @250MHz)
> 5000A/8000A wideband lightening/surge protector (low insertion loss
> @0.2dB or better)
> RF Wideband Power Amp to match antenna
> Low pass filter - cutoff 2.2GHz
See power amp cautions as above.
The WBX already has a 2.2GHz LPF on the output, as I recall.
>
> WBX (Rx)
> Wideband Rx Antenna (either 50-2200MHz or to the top end of the Basic
> Rx @250MHz, possibly Active Antenna)
> 5000A/8000A wideband lightening/surge protector (low insertion loss
> @0.2dB or better)
> Wideband LNA to match antenna (or use active antenna)
> Low pass filter - cutoff 2.2GHz
See cautions about linearity. In any reasonable suburban/urban
setting, letting the front-end just "soak up whatever is out there" is
generally
unwise, at least if you care about quality and the ability to pick
out weak signals.
>
> To prevent transient pulses from damaging the B100 that are not enough
> to trigger the surge protector (I think these kick in at 90Vpp), I
> require something that will attenuate input signals. I think you
> recommended -25dBm for the WBX. I didn't see a recommendation for the
> Basic Tx/Rx. Any good suggestions?
>
> Do you see any problems or anything I have missed?
>
> Regards,
The WBX already has TVS protection in the front end, and adding an
external GDT is a good idea.
If you're connecting directly to the BASIC_RX/BASIC_TX from an antenna a
GDT by itself should be sufficient.
In either case, if they're going to be sitting in strong RF fields, you
should consider attenuators, which can be purchased from a multitude of
vendors. But doing so will, necessarily, reduce your sensitivity.
From the type of questions, I'm getting that perhaps RF isn't really a
core expertise for you, and I would urge you to learn about RF engineering
before just "throwing a whole pile of equipment together". The ARRL
handbook, for example, offers a treasure-trove of fairly easy to understand
chapters on theory, and engineering considerations. I've acquired my
knowledge through *years* of experience, having been licensed as an
amateur radio operator since 1986, and worked in technology since
1979. There's still a lot I don't know, and unlike, for example, putting
a home entertainment system together, putting RF systems together
requires real *engineering* discipline. Mistakes in this area lead to
damaged equipment and/or systems that perform very poorly, not
because any given component is "bad", but because the overall
RF system design is not well considered.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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Message: 9
Date: Wed, 8 May 2013 03:07:14 +0100
From: Mark McCarron <[email protected]>
To: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Marcus,
Absolutely correct on the hardware side of things, I write DSP software and I'm
doing a deep-dive on the physical setup. Thanks for all your help. As I am
assembling all of this over the next month or so, no doubt I will pick your
brains.
Right now, I have a noise issue. I am using the WBX board. All throughout the
sub-1GHz band, I find the following noise pattern with limited gaps of 20MHz or
so now and again. They are narrow-band AM signals that are ever-so-slightly FM
modulated. See this image:
http://i.imgur.com/OSVhxp8.jpg
My area should be RF quiet and by that I mean absolutely dead unless cows can
broadcast.
I went to the 2-meter band and I found this:
http://i.imgur.com/0tbZt3x.jpg
Any idea what this is??? Or better yet, how to get rid of it?
Regards,
Mark McCarron
Date: Tue, 7 May 2013 21:19:48 -0400
From: [email protected]
To: [email protected]; [email protected]
Subject: Re: [USRP-users] USRP B100 Tuning Issue
On 05/07/2013 08:54 PM, Mark McCarron wrote:
Marcus,
That was an excellent explanation. You should write the user
manuals. :)
Is there a complete filter bank that spans 1-250MHz that can be
interfaced either through USB or the B100?
Not that I'm aware of. Such "filter banks" usually aren't done as a
separate commercial module, but usually integrated into the
front-end of some types of receivers.
I had been reading other posts of yours because I am trying to
create a proper antenna setup. I see that the Basic Rx/Tx have
different input specs from the WBX. 2Vpp and 0.2Vpp
respectively. I didn't see any specs on the maximum input
current.
Well, the input impedance is 50 ohms, so ohms law. The WBX is a
full analog downconverter with a complete RF gain chain, mixers,
etc. It's
more along the lines of what you'd expect for a
wants-to-be-plugged-into-an-antenna receiver for 50Mhz to 2.2GHz, so
the maximum input levels
are very much lower, as you would expect. Generally in RF, we
refer everything to dBm, usually in a 50Ohm system, rather than
talking about
P-P voltage levels. That's just the way the RF industry "works".
So far, I have come up with this basic list:
Basic Tx
Wideband Tx Antenna (either 1-250MHz or to the bottom end of the
WBX @50MHz)
5000A/8000A wideband lightening/surge protector (low insertion
loss @0.2dB or better)
RF Wideband Power Amp to match antenna
Low pass filter - cutoff 250MHz
I'd again urge caution in the use of RF power amps at arbitrary
frequencies. That's likely to get unwanted attention not only from
law enforcement, but other properly-licensed users of the same
spectrum.
Basic Rx
Wideband Rx Antenna (either 1-250MHz or to the bottom end of the
WBX @50MHz, possibly Active Antenna)
5000A/8000A wideband lightening/surge protector (low insertion
loss @0.2dB or better)
Wideband LNA to match antenna (or use active antenna)
Low pass filter - cutoff 250MHz
For terrestrial applications below 50Mhz or so, there's no point in
trying to even *design* a *true* low-noise amplifier.
Terrestrial and background galactic noise will utterly dominate
any noise added by the electronics themselves.
Also, below about 1GHz, it's hard to find low-noise amplifiers with
enough dynamic range (expressed as p1dB and OIP3)
that you can do without application-specific filtering. The RF
spectrum is *really crowded* these days, and strong signals
are everywhere that can easily drive your nice little LNA into
non-linear territory without app-specific filtering.
WBX (Tx)
Wideband Tx Antenna (either 50-2200MHz or to the top end of the
Basic Tx @250MHz)
5000A/8000A wideband lightening/surge protector (low insertion
loss @0.2dB or better)
RF Wideband Power Amp to match antenna
Low pass filter - cutoff 2.2GHz
See power amp cautions as above.
The WBX already has a 2.2GHz LPF on the output, as I recall.
WBX (Rx)
Wideband Rx Antenna (either 50-2200MHz or to the top end of the
Basic Rx @250MHz, possibly Active Antenna)
5000A/8000A wideband lightening/surge protector (low insertion
loss @0.2dB or better)
Wideband LNA to match antenna (or use active antenna)
Low pass filter - cutoff 2.2GHz
See cautions about linearity. In any reasonable suburban/urban
setting, letting the front-end just "soak up whatever is out there"
is generally
unwise, at least if you care about quality and the ability to pick
out weak signals.
To prevent transient pulses from damaging the B100 that are not
enough to trigger the surge protector (I think these kick in at
90Vpp), I require something that will attenuate input signals.
I think you recommended -25dBm for the WBX. I didn't see a
recommendation for the Basic Tx/Rx. Any good suggestions?
Do you see any problems or anything I have missed?
Regards,
The WBX already has TVS protection in the front end, and adding an
external GDT is a good idea.
If you're connecting directly to the BASIC_RX/BASIC_TX from an
antenna a GDT by itself should be sufficient.
In either case, if they're going to be sitting in strong RF fields,
you should consider attenuators, which can be purchased from a
multitude of
vendors. But doing so will, necessarily, reduce your sensitivity.
From the type of questions, I'm getting that perhaps RF isn't really
a core expertise for you, and I would urge you to learn about RF
engineering
before just "throwing a whole pile of equipment together". The
ARRL handbook, for example, offers a treasure-trove of fairly easy
to understand
chapters on theory, and engineering considerations. I've acquired
my knowledge through *years* of experience, having been licensed as
an
amateur radio operator since 1986, and worked in technology since
1979. There's still a lot I don't know, and unlike, for example,
putting
a home entertainment system together, putting RF systems together
requires real *engineering* discipline. Mistakes in this area lead
to
damaged equipment and/or systems that perform very poorly, not
because any given component is "bad", but because the overall
RF system design is not well considered.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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------------------------------
Message: 10
Date: Tue, 07 May 2013 22:13:07 -0400
From: "Marcus D. Leech" <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
> Marcus,
>
> Absolutely correct on the hardware side of things, I write DSP
> software and I'm doing a deep-dive on the physical setup. Thanks for
> all your help. As I am assembling all of this over the next month or
> so, no doubt I will pick your brains.
>
> Right now, I have a noise issue. I am using the WBX board. All
> throughout the sub-1GHz band, I find the following noise pattern with
> limited gaps of 20MHz or so now and again. They are narrow-band AM
> signals that are ever-so-slightly FM modulated. See this image:
>
> http://i.imgur.com/OSVhxp8.jpg
>
> My area should be RF quiet and by that I mean absolutely dead unless
> cows can broadcast.
>
> I went to the 2-meter band and I found this:
>
> http://i.imgur.com/0tbZt3x.jpg
>
> Any idea what this is??? Or better yet, how to get rid of it?
>
> Regards,
>
> Mark McCarron
Hard to tell from just looking at a the spectra. My guess, would be
digital noise from your own equipment.
RF noise even "out with the cows" can be a real problem if you're
observing near the noise floor. Particularly as noise figures of LNAs
continue to plummet, stuff that 20 years ago your receiver wouldn't
have noticed, now sticks out like a sore thumb.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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------------------------------
Message: 11
Date: Wed, 8 May 2013 05:21:42 +0100
From: Mark McCarron <[email protected]>
To: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Marcus,
I powered down everything in the house and switched to a laptop. There was no
change. Have a look:
http://i.imgur.com/JIiUHwL.jpg
I added a little gain to that signal on 2 meters...:
http://i.imgur.com/jEPgyyM.jpg
I pulled the antenna from the USRP and it appears to be internal. Is this
normal? It looks like this board or box may be defective. I'll contact Ettus
Research and find out.
Regards,
Mark McCarron
Date: Tue, 7 May 2013 22:13:07 -0400
From: [email protected]
To: [email protected]
Subject: Re: [USRP-users] USRP B100 Tuning Issue
Marcus,
Absolutely correct on the hardware side of things, I write DSP
software and I'm doing a deep-dive on the physical setup.
Thanks for all your help. As I am assembling all of this over
the next month or so, no doubt I will pick your brains.
Right now, I have a noise issue. I am using the WBX board. All
throughout the sub-1GHz band, I find the following noise pattern
with limited gaps of 20MHz or so now and again. They are
narrow-band AM signals that are ever-so-slightly FM modulated.
See this image:
http://i.imgur.com/OSVhxp8.jpg
My area should be RF quiet and by that I mean absolutely dead
unless cows can broadcast.
I went to the 2-meter band and I found this:
http://i.imgur.com/0tbZt3x.jpg
Any idea what this is??? Or better yet, how to get rid of it?
Regards,
Mark McCarron
Hard to tell from just looking at a the spectra. My guess, would be
digital noise from your own equipment.
RF noise even "out with the cows" can be a real problem if you're
observing near the noise floor. Particularly as noise figures of
LNAs
continue to plummet, stuff that 20 years ago your receiver
wouldn't have noticed, now sticks out like a sore thumb.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
_______________________________________________
USRP-users mailing list
[email protected]
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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------------------------------
Message: 12
Date: Wed, 8 May 2013 10:21:01 +0000 (UTC)
From: Raja Sattiraju <[email protected]>
To: [email protected]
Subject: [USRP-users] UHD driver for Matlab R2012b
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
Hello all,
There seems to be no UHD driver for version Communications systems toolbox
(V5.3)in the official mathworks page. Do I need to switch back to R2012a or
wait for the latest version?
Many thanks,
Raja
------------------------------
Message: 13
Date: Wed, 08 May 2013 19:43:54 +0800
From: Gong Zhang <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [USRP-users] Document about the FPGA
Message-ID: <[email protected]>
Content-Type: text/plain; charset=GB2312
Hi,
Is there any detail document about the FPGA part of UHD? Is reading the
source code the only way to go deep into the FPGA part?
Thanks.
------------------------------
Message: 14
Date: Wed, 8 May 2013 12:02:49 +0000
From: Mike McLernon <[email protected]>
To: Raja Sattiraju <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] UHD driver for Matlab R2012b
Message-ID:
<e3879be9a282cb45aab7ce258a9ae48f21a22...@exmb-01-ah.ad.mathworks.com>
Content-Type: text/plain; charset="utf-8"
Hi Raja,
See
http://www.mathworks.com/support/solutions/en/data/1-M28V7O/index.html?solution=1-M28V7O,
and look for the section on R2012b.
Hth,
Mike
-----Original Message-----
From: USRP-users [mailto:[email protected]] On Behalf Of Raja
Sattiraju
Sent: Wednesday, May 08, 2013 6:21 AM
To: [email protected]
Subject: [USRP-users] UHD driver for Matlab R2012b
Hello all,
There seems to be no UHD driver for version Communications systems toolbox
(V5.3)in the official mathworks page. Do I need to switch back to R2012a or
wait for the latest version?
Many thanks,
Raja
_______________________________________________
USRP-users mailing list
[email protected]
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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------------------------------
Subject: Digest Footer
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------------------------------
End of USRP-users Digest, Vol 33, Issue 7
*****************************************
