Hi Alexander.
As I understand, you ask about output signal difference when TXVGA2=25,
isn't it?
Actually I missed it before.
I am sure that difference much less then 2-3dB as you mentioned, I think it
there was temperature effect.
Best regards,
Andrey Sviyazov.
2012/11/2 Alexander Chemeris <alexander.chemeris(a)gmail.com>
Andrey,
A stupid question. Why does "LDO" measurements have signal level 2-3dB
higher then "FPGA" measurements? Is it due to measurement inaccuracy
or it's an effect from the power supply change?
On Fri, Nov 2, 2012 at 5:41 AM, Andrey Sviyazov <andreysviyaz(a)gmail.com>
wrote:
Hi Jean-Samuel.
I spent a lot of time yesterday and this morning because I trying to fix
DC-DC issue which I mentioned few days ago (see pics).
Unfortunatelly, result seems close to zero so far.
I never saw so strange problems with dc-dc converters before.
I am sure that there are no problems in v1 and also that this problems
because of syncro mode.
Now I am trying to describe this issue, may be anybody have experience
with
this kind problem.
Let me know if you can help me here too.
Regarding +3.3V LDO regulators for LMS.
Here attached pics of noise plots with LDO's and when supplied from
+3.3VFPGA through TI1608U601.
I can't find any significant difference there.
I think we can replace LDO's by RF chokes without derating performances.
In this case, power consumption decreased to 11..12W in dependance of
values
TXVGA.
Regarding GSM spectrum requirements you mentioned.
As you can see, yesterday I've measured it again when made experiments
around +3.3V.
I found that we didn't meet requirements only when deep saturation occur.
I mean when TXVGA2 higher then 23 (i.e. 24 and 25).
Best regards,
Andrey Sviyazov.
2012/11/2 Jean-Samuel Najnudel - BJT PARTNERS SARL <jsn(a)bjtpartners.com>
>
> Hi Andrey,
>
>
> Thank you very muchf or your reply.
>
> Regarding the requirement at f +/- 400 KHz, the spec mentions our signal
> must be -60 dBc bellow the signal at f.
> You can get more details on the GSM 05.05 spec (part 4.2), from page 15.
>
http://p3e.rats.fi/oh2mqk/GSM/GSM-05.05.pdf
>
> To pass this spec, we need to get our phase noise bellow -113 dBc/Hz at
> 400 KHz.
> On last measurements, we either fail or just pass this spec.
> If possible, this would be great to try to tune the charge pump and the
> loop filter passives to get our phase noise as low as possible.
> I know you already worked on this and already improved this but, if you
> have some ideas to decrease a bit more the phase noise, this would be
very
> interesting.
>
> Best regards.
>
> Jean-Samuel.
> :-)
>
>
>
> On Wed, Oct 31, 2012 at 10:19 PM, Andrey Sviyazov <
andreysviyaz(a)gmail.com>
> wrote:
>>
>> Hi Jean-Samuel.
>>
>> About power consumption and performancea I can say that spurs at 500
kHz
>> offset around 6dB above TX LO noise
plot.
>> It wad measured when 3.3V come from dogs through TI2012U601.
>> Tomorrow I'll measure all again and share pics in this topic.
>> As I mentioned, I'll try to find better filter to suppress 500kHz.
>> Please let me know any partnumbers or suppliers you known.
>> Also unoccupied place under 3.3V LDO's near LMS seems a good place for
>> thermal sensors.
>> About rf connectors, now I am sure that MCX much better then U_FL and
we
>> should return them.
>> To connect UmSEL to UmTRX v2.1 required U_FL-MCX cable assemblies till
>> new UmSEL version.
>> Also possible to use direct cable soldering to UmSEL board.
>> Of course, last variant look not perfect.
>> About requirements at 400kHz we can't meet, I actually can't understand
>> what do you mean.
>>
>>
>>
>> Best regards,
>> Andrey Sviyazov.
>> (Sent from my mobile client)
>>
>> 31.10.2012 22:47 пользователь "Jean-Samuel Najnudel - BJT PARTNERS
SARL"
>> <jsn(a)bjtpartners.com> написал:
>>
>>> Hi Andrey,
>>>
>>> Do you think it will be possible to decrease the power consumption and
>>> to keep the best possible performances for industrial applications ?
>>> I know you cannot be sure about this but I would like to know how
>>> confident you feel about this ?
>>>
>>> Best regards.
>>>
>>> Jean-Samuel.
>>> :-)
>>>
>>>
>>> On Wed, Oct 31, 2012 at 7:40 PM, Andrey Sviyazov
>>> <andreysviyaz(a)gmail.com> wrote:
>>>>
>>>> Hi Jean-Samuel, Alexander.
>>>>
>>>> Tomorrow I'll let you know what possible to make on time.
>>>> And we should set time limit for this.
>>>> For example, next morning.
>>>>
>>>> Best regards,
>>>> Andrey Sviyazov.
>>>> (Sent from my mobile client)
>>>>
>>>> 31.10.2012 22:24 пользователь "Jean-Samuel Najnudel - BJT PARTNERS
>>>> SARL" <jsn(a)bjtpartners.com> написал:
>>>>
>>>>> Hi Alexander,
>>>>>
>>>>> Thank you very much for your reply.
>>>>>
>>>>> Why skip/populate LMS power supply block ?
>>>>> As I understand we always need the LMS power supply block. I
probably
>>>>> missed something. Could you
explain this in more details to let me
better
>>>>> understand ?
>>>>>
>>>>> Thanks a lot for your help.
>>>>>
>>>>> Best regards.
>>>>>
>>>>> Jean-Samuel.
>>>>> :-)
>>>>>
>>>>>
>>>>> On Wed, Oct 31, 2012 at 7:14 PM, Alexander Chemeris
>>>>> <alexander.chemeris(a)gmail.com> wrote:
>>>>>>
>>>>>> Yes, lesser input voltage range makes sense only if it saves
>$10
>>>>>> and/or considerably increases power efficiency. I think this not
the
>>>>>> case, and then only these
changes will be needed:
>>>>>>
>>>>>> * traditional power connector
>>>>>> * MCX RF connector, because they sustain much more
connect-disconnect
>>>>>> cycles
>>>>>> * lower power consumption mod
>>>>>>
>>>>>> I would appreciate if we could keep the same PCB for both
versions
>>>>>> and
>>>>>> populate the proper version of power connector/RF connector and
>>>>>> skip/populate LMS power supply block.
>>>>>>
>>>>>> On Wed, Oct 31, 2012 at 9:56 PM, Jean-Samuel Najnudel - BJT
PARTNERS
>>>>>> SARL
<jsn(a)bjtpartners.com> wrote:
>>>>>> > Hi Alexander,
>>>>>> >
>>>>>> > This would be much easier to have the same board for both
lab and
>>>>>> > deployment. Only the UmSEL would make the difference.
>>>>>> > For deployment, I really need wide input voltage range as I
plan
to
>>>>>> > power
>>>>>> > the whole system (UmTRX + PA) with a single 28V supply.
>>>>>> > Even if this can save a few euros, I would really prefer we
do
not
>>>>>> > make the
>>>>>> > input voltage range smaller.
>>>>>> > By the way, even for lab, it might be convenient and it can
avoid
>>>>>> > damages in
>>>>>> > case of wrong voltage supply.
>>>>>> >
>>>>>> > Best regards.
>>>>>> >
>>>>>> > Jean-Samuel.
>>>>>> > :-)
>>>>>> >
>>>>>> >
>>>>>> >
>>>>>> > On Wed, Oct 31, 2012 at 6:50 PM, Alexander Chemeris
>>>>>> > <alexander.chemeris(a)gmail.com> wrote:
>>>>>> >>
>>>>>> >> Andrey, how much time do you need to create 2.1? If
it's mire
than
>>>>>> >> a day,
>>>>>> >> we should postpone this. I believe that enclosure is a
much more
>>>>>> >> important
>>>>>> >> issue at this moment.
>>>>>> >>
>>>>>> >> I think we need following changes for the lab version:
>>>>>> >> * traditional power connector
>>>>>> >> * MCX RF connector, because they sustain much more
>>>>>> >> connect-disconnect
>>>>>> >> cycles
>>>>>> >> * lower power consumption mod
>>>>>> >> * smaller input voltage range (only if this makes things
cheaper)
>>>>>> >>
>>>>>> >> Sent from my Android device.
>>>>>> >>
>>>>>> >> --
>>>>>> >> Regards,
>>>>>> >> Alexander Chemeris
>>>>>> >> CEO, Fairwaves LLC
>>>>>> >>
http://fairwaves.ru
>>>>>> >>
>>>>>> >> 31.10.2012 14:05 пользователь "Andrey
Sviyazov"
>>>>>> >> <andreysviyaz(a)gmail.com>
>>>>>> >> написал:
>>>>>> >>
>>>>>> >>> Hi Jean-Samuel.
>>>>>> >>>
>>>>>> >>> First of all, you didn't said about delay
duration :)
>>>>>> >>> I can't delay this batch just due to my wishes
that each next
>>>>>> >>> batch
>>>>>> >>> should work more and more ideally.
>>>>>> >>>
>>>>>> >>>> These modifications looks interesting. I think
it is a good
>>>>>> >>>> idea.
>>>>>> >>>
>>>>>> >>> Hope so.
>>>>>> >>>
>>>>>> >>>>
>>>>>> >>>> I just have a few question.
>>>>>> >>>>
>>>>>> >>>> Why do you call this board revision 2.1 "a
special batch for
>>>>>> >>>> labs" ?
>>>>>> >>>> Would these modifications make this revision 2.1
also more
>>>>>> >>>> suitable for
>>>>>> >>>> field deployment, at least as much as the
revision 2.0 ?
>>>>>> >>>
>>>>>> >>> Because of I can fix only known issues.
>>>>>> >>> Also not all really required improvements are known
yet.
>>>>>> >>>
>>>>>> >>>> Decreasing power consumption to 10..11 W would
be great. Is
>>>>>> >>>> there any
>>>>>> >>>> drawbacks of this modification ? Would it
decrease some
>>>>>> >>>> performances ? If
>>>>>> >>>> not, this modifiction to decrease power
consumption is a
>>>>>> >>>> significant very
>>>>>> >>>> good modification.
>>>>>> >>>
>>>>>> >>> Decreasing of performances it is only spurs with
DC/DC
conversion
>>>>>> >>> freq
>>>>>> >>> ~500kHz.
>>>>>> >>> Now I searching more good LC filter to suppress it
better than
>>>>>> >>> TI2012U601
>>>>>> >>> can.
>>>>>> >>>
>>>>>> >>>> Do you have enough space on the board to replace
some U_FL
>>>>>> >>>> connectors
>>>>>> >>>> with MCX connectors as you suggest ?
>>>>>> >>>
>>>>>> >>> Yes, but may be not all should be MCX.
>>>>>> >>> Of course I did not insist, but just asking whether
there is a
>>>>>> >>> reason to
>>>>>> >>> do it or not.
>>>>>> >>>
>>>>>> >>>> An external LNA would probably need around 5
Volts instead of
>>>>>> >>>> 6V. A
>>>>>> >>>> small PA would probably need a little bit higher
voltage. Do
you
>>>>>> >>>> think
it
>>>>>> >>>> would be possible to have a variable voltage low
power
connector
>>>>>> >>>> ?
>>>>>> >>>
>>>>>> >>> On my opinion, variable voltage is not good idea.
>>>>>> >>> For example for LNA's better to place low noise
LDO 6V to 5V
near
>>>>>> >>> to IC's
>>>>>> >>> to get Vcc clean too.
>>>>>> >>>
>>>>>> >>>> By the way, could you pelase also add the 2 LMS
output
matching
>>>> >>>> capacitors we need to
improve output power figures in the 1800
>>>> >>>> band ?
>>>> >>>
>>>> >>> Of course, because it is issue which should be fixed, but
not
>>>> >>> improvement.
>>>> >>>
>>>> >>> Best regards,
>>>> >>> Andrey Sviyazov.
>>>> >
>>>> >
>>>>
>>>>
>>>>
>>>> --
>>>> Regards,
>>>> Alexander Chemeris.
>>>> CEO, Fairwaves LLC / ООО УмРадио
>>>>
http://fairwaves.ru
>>>
>>>
>
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru