Yes, it is 1 Mohm, and my probe is set to 1X.
Khalid
On Tue, Jan 6, 2015 at 3:33 PM, Nick Foster <bistrom...@gmail.com
<mailto:bistrom...@gmail.com>> wrote:
Is the input impedance of your scope 1Mohm or 50 ohms? You sure
you have the voltage multiplier (1x/10x) set correctly?
On Tue, Jan 6, 2015 at 11:01 AM, khalid.el-darymli
<khalid.el-dary...@mun.ca <mailto:khalid.el-dary...@mun.ca>> wrote:
>> Trying setting a gain in your sink block of, let's say,
20dB, with a magnitude of 0.9. What power output do you get?
How are you measuring power?
This gives me 23.2 mV (peak to peak). This is the reading I
get from a scope connected to a T. For the input ends of the
T, one end is connected to a 50-ohm terminator and the other
end is connected to the output from LFTX. This gives a power
of: 30+10 log_10[{23.2e-03/[2*sqrt(2)]}^2/50]= *-28.711* dBm.
>> What is your flow-graph actually doing? Have you tried both
connectors on the LFTX?
Simple, a signal source (Sine) block directly connected to a
USRP Sink block.
Yes, both connectors on the LFTX daughterboard give the same
voltage reading.
Thanks,
Khalid
On Tue, Jan 6, 2015 at 2:34 PM, Marcus D. Leech
<mle...@ripnet.com <mailto:mle...@ripnet.com>> wrote:
>> Output power is determined largely by baseband signal
magnitude in that case.
Yes, I understand. And I noticed that for baseband
signal with an amplitude *> 1, * the pass-band signal
gets clipped off. So I assume that an amplitude of 1 for
the baseband signal should deliver the maximum output
power (for the pass-band signal).
My question was, what is the maximum power one can get
for the pass-band signal output from LFTX? In your
earlier reply, you said it is around +7dBm, am I getting
this right? In my case, for a baseband amplitude of
around 1, I am only getting *-28.13dBm*, much less than
what you said, I am not sure,*why?*
Thanks,
Khalid
For a magnitude of ~1, you should see maximum amplitude
signals coming out of it.
You could try setting gain, but on any platforms with
VGAs in the DAC, there's only about 6dB of gain range
settable. Trying setting a gain in your
sink block of, let's say, 20dB, with a magnitude of
0.9. What power output do you get? How are you
measuring power? What is your flow-graph
actually doing? Have you tried both connectors on the
LFTX?
On Tue, Jan 6, 2015 at 1:56 PM, Marcus D. Leech
<mle...@ripnet.com <mailto:mle...@ripnet.com>> wrote:
Thanks Marcus for your reply.
>> Probably somewhere in the neighborhood of +7dBm,
maybe a little more.
>> The LF/BASIC series have *no* gain in either
path, so you're just looked
at buffered ADC ouput.
So, ~ *+7dBm* is the max output power I supposed to
get from the LFTX daughterboard? How do I get that?
Since I am only getting -28.13 dBm, does that mean
I have some issue with my LFTX daughterboard?
Khalid
Output power is determined largely by baseband
signal magnitude in that case.
Message: 2
Date: Tue, 6 Jan 2015 10:13:45 -0330
From: "khalid.el-darymli" <khalid.el-dary...@mun.ca
<mailto:khalid.el-dary...@mun.ca>>
To: "Discuss-gnuradio@gnu.org
<mailto:Discuss-gnuradio@gnu.org>"
<discuss-gnuradio@gnu.org
<mailto:discuss-gnuradio@gnu.org>>
Subject: [Discuss-gnuradio] Max Output Power from
the LFTX
daughterboard
Message-ID:
<CACdmG=zCHATiwrtv=wBVLwG0_
5GQr0y=wksequrcajrtuv5...@mail.gmail.com
<mailto:wksequrcajrtuv5...@mail.gmail.com>>
Content-Type: text/plain; charset="utf-8"
Hi,
What is the maximum output power from the LFTX
daughterboard when used with
the USRP N200?
According to this datasheet [1], the N200 with the
WBX daughterbaord
provide an output power of 15 dBm. However, when
using the LFTX
daughterboard, I am getting a much less output power.
[1]
http://www.ettus.com/content/files/07495_Ettus_N200-210_DS_Flyer_HR.pdf
In GNU Radio with the USRP N200, we use a sinusoid
with a frequency of 150
kHz and an amplitude of 0.98, fed into the LFTX
daughterboard for a center
frequency of 5 MHz. When the output of LFTX is
plugged into a scope
terminated with a 50-ohm terminator, the scope
reads 24.8 mV
(peak-to-peak). This is around -28.13 dBm.
Is this the max power one can get out of the LFTX
daughterboard?
Thanks.
Best regards,
Khalid
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Message: 3
Date: Tue, 06 Jan 2015 08:48:08 -0500
From: "Marcus D. Leech" <mle...@ripnet.com
<mailto:mle...@ripnet.com>>
To: discuss-gnuradio@gnu.org
<mailto:discuss-gnuradio@gnu.org>
Subject: Re: [Discuss-gnuradio] Max Output Power
from the LFTX
daughterboard
Message-ID: <54abe798.5060...@ripnet.com
<mailto:54abe798.5060...@ripnet.com>>
Content-Type: text/plain; charset=UTF-8; format=flowed
On 01/06/2015 08:43 AM, khalid.el-darymli wrote:
> Hi,
>
> What is the maximum output power from the LFTX
daughterboard when used
> with the USRP N200?
>
> According to this datasheet [1], the N200 with
the WBX daughterbaord
> provide an output power of 15 dBm. However, when
using the LFTX
> daughterboard, I am getting a much less output power.
> [1]
>
http://www.ettus.com/content/files/07495_Ettus_N200-210_DS_Flyer_HR.pdf
>
> In GNU Radio with the USRP N200, we use a
sinusoid with a frequency of
> 150 kHz and an amplitude of 0.98, fed into the
LFTX daughterboard for
> a center frequency of 5 MHz. When the output of
LFTX is plugged into a
> scope terminated with a 50-ohm terminator, the
scope reads 24.8 mV
> (peak-to-peak). This is around -28.13 dBm.
>
> Is this the max power one can get out of the LFTX
daughterboard?
>
>
> Thanks.
>
> Best regards,
> Khalid
Probably somewhere in the neighborhood of +7dBm,
maybe a little more.
The LF/BASIC series have *no* gain in either path,
so you're just looked
at buffered ADC ouput.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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