[Radioig] voltage UCD?

Tue Apr 4 11:30:44 CEST 2023

Hi all,

Thank you all for clarifications.

As far as the UCD vocabulary is concerned , I will wait for a refined 
use case
to go further in the proposal for a new term.

Thanks , Mireille

Le 04/04/2023 à 11:13, Markus Dolensky a écrit :
> Hi again,
>
> Meanwhile, it has turned out that stat.fourier is not a match, because ...
>
> @Mark:
> ... it's channelized, dual-polarisation, beamformed voltages. So, the
> data product is primarily a time series of complex voltages (amplitude
> and phase). Mentioning PSRFITS was somewhat distracting. Upon further
> investigation it turns out that the format was an earlier design
> assumption. As is the format does not support such voltages.
>
> @All:
> Clearly, the design of the voltage recording data product needs to
> settle, before we can make the case for a new UCD.
>
> Apparently, I've stumbled across a new use case. So, thanks all for
> helping to clarify.
>
> Best
> Markus
>
>
> On 31/3/2023 19:40, Mark Kettenis wrote:
>>> From: Markus Dolensky <markus.dolensky at uwa.edu.au>
>>> Date: Fri, 31 Mar 2023 08:16:47 +0000
>> Hi Markus Do & others,
>>
>>> Hi Markus De., Francois, Mireille,
>>>
>>> @Markus De:
>>> We are talking about raw (calib_level = 0), complex voltage data (o_ucd =
>>> stat.fourier?) from a future radio interferometer that records them in near
>>> realtime (dataproduct_type = timeseries).
>> Correct me if I'm wrong, but I think what you're really talking about
>> is "I/Q data" that describes the in-phase (I) and quadrature (Q)
>> components of a (downmixed) signal.  The I and Q components are often
>> combined in a single complex number but that really is just a
>> mathematical convenience.
>>
>> Note that reconstruction of the original signal (which is presumably
>> what is needed/wanted in the subsequent analysis) you need to know the
>> frequency of the mixer signal (LO) that was used to construct the I
>> and Q components.
>>
>>> So yes, stat.fourier is a possible candidate. I will try to source an
>>> opinion from one of the Pulsar astronomers designing the data product.
>> The existence of stat.fourier.amplitude suggests that stat.fourier
>> would indeed be complex number; but the I/Q representation isn't
>> really a fourier transform of the original signal...
>>
>> Is a new UCD "atom" that indicates I/Q data appropriate?  With the
>> understanding that this would be a complex number?  Not sure if there
>> is a need to have a UCD that represents the indivicual I and Q
>> components.
>>
>>> I have taken note of the UCD maintenance process.
>>>
>>> @Francois
>>> re ObsCore extension and ADU:
>>> Likewise, I'm following up with the pulsar team on the nature of the voltage
>>> data. Timezone difference suggests that won't happen before next week.
>>>
>>> @Mireille
>>> Thanks a lot for jump-starting the RFM.
>>>
>>> @All
>>> Depending on said internal clarifications, we may or may not propose
>>> something new. Given that the respective data product does not yet exist,
>>> there is no particular urgency and no shortage of uncertainty.
>>>
>>> For now, thanks for the great considerate responses!
>>> Markus
>>>
>>> Markus Dolensky
>>> Technical Leader
>>> International Centre for Radio Astronomy Research
>>> The University of Western Australia | M468, 35 Stirling Highway | Perth WA
>>> 6009
>>> T +61 8 6488 5072
>>>
>>> On 30/3/2023 22:33, Mireille LOUYS wrote:
>>>
>>>    Hi Markus , hi radio astronomers,
>>>
>>>    I think we can discuss the definition of a new term, if the requirement
>>>    is to label a measurement corresponding to some voltage.
>>>
>>>    The current procedure for UCD addition is to prepare a short document to
>>>    explain the context for adding a new term.
>>>    This can be done in a short file called VEP-UCD.
>>>    I have prepared such a file , as included here below.
>>>
>>>    The first step is to discuss the detailed information of the VEP, and
>>>    the group can finalise the requirement for this UCD :
>>>
>>>    here is my proposal , to be completed by your inputs as
>>>    radioastronomers.
>>>
>>>    ----  starts of: VEP-UCD-012_voltage------
>>>    Vocabulary extension proposal for UCDs /
>>>    Vocabulary: UCDlist 1.6
>>>    Author: mireille louys for radio interest group
>>>    Date: 2023-03-29
>>>
>>>    New Term: phys.voltage
>>>    Action: Addition
>>>    Label: Voltage (measured by an instrument)
>>>    Prefix: Q
>>>    Description:  Voltage quantity
>>>     
>>>    Relationships: can be combined with instr.param for observing
>>>    configuration
>>>    Rationale:
>>>    Radio data in raw format can measure a voltage quantity as signal,
>>>    before the data is calibrated.
>>>    'phys.voltage' can be used as well to identify a parameter of the
>>>    observation configuration used with an instrument.
>>>
>>>    Discussion:
>>>    To be completed by radio and semantics WG remarks
>>>    Pros and cons ...
>>>    Other existing ucd terms that can be used instead...
>>>
>>>    Response: (To be completed by UCD board after discussion)
>>>
>>>    ----  end of VEP-UCD-012_voltage------
>>>
>>>    When we agree, this can be added on the RequestForModificationPage here:
>>>    https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwiki.ivoa.net%2Ftwiki%2Fbin%2Fview%2FIVOA%2FUCDList_1-6_RFM&data=05%7C01%7Cmarkus.dolensky%40uwa.edu.au%7Cd2c757102bb543bc8b5f08db31dcc714%7C05894af0cb2846d8871674cdb46e2226%7C0%7C0%7C638158597453614121%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=HYgQCepCGS%2F2RDAjLR%2BDhRgLuKyW4MN3pn9dxLhUGu0%3D&reserved=0
>>>
>>>    many thanks for your inputs to finalise this first step.
>>>
>>>    cheers , Mireille
>>>
>>>    Le 30/03/2023 à 13:21, Markus Demleitner a écrit :
>>>
>>>    Hi Markus,
>>>
>>> On Tue, Mar 28, 2023 at 06:30:55AM +0000, Markus Dolensky wrote:
>>>
>>>    Can somebody suggest a UCD for complex voltage data, please?
>>>
>>> Context is the Obscore o_ucd for PSRFITS data.
>>>
>>> Hm... it would seem nobody has an immediate solution, and reviewing
>>> the current UCD list make me suspect there's nothing remotely
>>> matching -- although I have to admit that I've no clue of PSRFITS...
>>> Does what you'd like to annotate have a complex part because of phase
>>> information in a fourier transform?  If so, perhaps stat.fourier
>>> could remotely work?
>>>
>>> With that caveat, I suppose the Right Thing™ to do would be to
>>> propose a new UCD.  This is less of a hassle than it might sound like
>>> -- see
>>> https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fivoa.net%2Fdocuments%2FUCDlistMaintenance%2F20191007%2FREC-UCDlistMaintenance-2.0-20191007.pdf&data=05%7C01%7Cmarkus.dolensky%40uwa.edu.au%7Cd2c757102bb543bc8b5f08db31dcc714%7C05894af0cb2846d8871674cdb46e2226%7C0%7C0%7C638158597453614121%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=NBEV%2Bb3KdFXuXTAEsX4%2F0tvOzPDCrPz7JgbVh07kW1A%3D&reserved=0.
>>>
>>> However, I suppose it would be a good idea to discuss the RFM here
>>> first before handing it over to Semantics.
>>>
>>>            -- Markus
>>>
>>> -- 
>>> --
>>> Mireille Louys,  MCF (Associate Professor)
>>> Centre de données CDS		IPSEO, Images, Laboratoire Icube
>>> Observatoire de Strasbourg	Telecom Physique Strasbourg
>>> 11 rue de l'Université		300, Bd Sebastien Brandt CS 10413
>>> F- 67000-STRASBOURG		F-67412 ILLKIRCH Cedex
>>> Tel: +33 3 68 85 24 34

-- 
--
Mireille Louys,  MCF (Associate Professor)
Centre de données CDS		IPSEO, Images, Laboratoire Icube
Observatoire de Strasbourg	Telecom Physique Strasbourg
11 rue de l'Université		300, Bd Sebastien Brandt CS 10413
F- 67000-STRASBOURG		F-67412 ILLKIRCH Cedex
Tel: +33 3 68 85 24 34