<div dir="ltr"><div dir="ltr">Hi folks,<div><br></div><div>Woah - thanks for the numerous helpful responses! I will contact those people suggested. </div><div><br></div><div>"<span style="font-family:monospace">you need all the subbands to go back"</span></div><div><br>Ah yes, 488 is not 512 ...</div><div><br></div><div>Thanks again!</div><div>Evan</div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Ar Déar 11 Meith 2020 ag 09:08, scríobh Joeri van Leeuwen <<a href="mailto:leeuwen@astron.nl">leeuwen@astron.nl</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<br>
<tt>Hi Evan, all,<br>
<br>
Apertif uses the same PFB and there too Eric Kooistra and I looked
into it. The filterbank is critically sampled as Ben writes, which
is an issue. One more problem (depending on the stage at which you
want to the inversion) as that you need all the subbands to go
back, so after subband selection you have an information deficit.
Eric most likely has a Matlab model. <br>
<br>
Cheers,<br>
Joeri<br>
<br>
==<br>
<br>
</tt><br>
<div>On 11-6-2020 09:57, Benjamin Stappers
wrote:<br>
</div>
<blockquote type="cite">
Hi Evan,
<div><br>
</div>
<div>I don’t have anything quickly to hand, but I can
take a look. On the inversion,</div>
<div>we looked into some of this a long time back for the
Cosmic Ray work and </div>
<div>I believe that there was a student, I could find out
her name and details who</div>
<div>worked on that. However, my memory is such that
while it is possible in theory</div>
<div>it isn’t actually possible unless you do a
oversampled polyphase like the ASKAP</div>
<div>one and the one proposed for SKA-Low. </div>
<div><br>
</div>
<div>Cheers - Ben</div>
<div><br>
<div><br>
<blockquote type="cite">
<div>On 11 Jun 2020, at 08:52, Evan Keane <<a href="mailto:evan.keane@gmail.com" target="_blank">evan.keane@gmail.com</a>>
wrote:</div>
<br>
<div>
<div dir="ltr">Hi PWG,
<div><br>
</div>
<div>Does anyone have to hand a
paper/document/anything describing the LOFAR polyphase
filterbank in the RSP boards, or a model for them? The
kind of thing I could run on (say) some simulated
Nyquist voltages to get a LOFAR RSP like response?
And, related, any attempts to invert the polyphase
filterbank?</div>
<div><br>
</div>
<div>Evan</div>
<div>
<div><br>
</div>
-- <br>
<div dir="ltr">
<div dir="ltr">
<div>
<div dir="ltr">Is mise le meas,<br>
Dr. E. F. Keane
<div>
<div><br>
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<div>***************************************************************</div>
<div>Ben Stappers</div>
<div>Head of Pulsar and Time Domain Astronomy Group</div>
<div>MeerTRAP Project Lead</div>
<div>Jodrell Bank Centre for Astrophysics</div>
<div>Department of Physics and Astronomy</div>
<div>The University of Manchester</div>
<div>Phone: +44 161 2754187</div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr">Is mise le meas,<br>Dr. E. F. Keane<div><div><br><div>**Smaoinigh ar an timpeallacht - an gcaithfidh tú an r-phost seo a phriontáil?**<br>**Please consider the environment before printing this email**</div></div></div></div></div></div></div>