# RA blocks **URL:** \ **Category:** GNU Radio\ **Created:** [June 22, 2013, 4:13am UTC](https://www.ruby-forum.com/t/ra-blocks/235450 "2013-06-22T04:13:24Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![alcina](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a587f6/32.png) [@alcina](https://www.ruby-forum.com/u/alcina)\ **Post date:** [June 22, 2013, 4:13am UTC](https://www.ruby-forum.com/t/ra-blocks/235450/1 "2013-06-22T04:13:24Z")
I’ve put a set of Radio Astronomy-related blocks up on cgran: [https://www.cgran.org/svn/projects/gr-ra\_blocks](https://www.cgran.org/svn/projects/gr-ra_blocks) It includes o an oblivous “slicer” that can be used in a Dicke-switching environment when there’s no way of explicitly tagging samples as to which “switch state” they belong to. It requires that there be a significant power difference between “Sky”, and “Reference”. It’s a decimator. o A synchronous detector. Like above–again used in Dicke switching, but it has an explicit switch-state input. It’s left as an exercise for the reader as to how you actually synchronize the internal notion of the switch state with the switch hardware, and the resulting data-streams, given the latency-uncertainties of Gnu Radio. Like the above, it’s a decimator. o A “clock generator”. It takes a sample-stream as input, and produces a series of (logical) 1s and 0s as an output, using the input stream purely as a timing source. It’s a decimator, so you can produce any integer-fractional rate of the incoming data stream. One might use this block to provide “switch state” to the synchronous detector block, above, perhaps with a delay block in between. o A “vector power” block (not sure what to actually call this). It takes a vector as input, usually the output magnitude vector of a previous FFT, and allows you to synthesize sub-channels by combining numbers of adjacent FFT output bins into a signal power estimate for that collection of bins. This is cheaper than a PFB, but is useful only for power estimation, since generally, it takes an already-IIR-filtered-and-decimated stream of FFT output vectors as input, and allows non-uniform output channels cheaply. o A pulsar folder – of the true folding type. It produces a fixed vector as output which hopefully contains the folded pulse profile. The input sample-rate must have already been fractionally-resampled to vector\_size \* notional-pulse-rate o Another pulsar folder – using an IIR output filter. Same sample-rate constraints as the “true folder”, but it produces continuous vector outputs, and applies a single-pole IIR filter to each element of the output vector. This is a GRC-derived hier block. o An RA-friendly FFT block – very much like the Log Power FFT block, but with linear magnitude outputs. Nothing fancy. It’s a GRC-derived hier block. I’ll likely add others as time and inspiration permit. For example, a hier block that can be used for coherent de-dispersion where you just give it the DM, Fc, and bandwidth, and let it compute the filter coefficients. I have Python “helper code” that can do this already, just not sure how to integrate it into a hier block “cleanly”. Similarly, an incoherent de-dispersion block using filter-and-delay might also be useful–again taking DM, Fc, and bandwidth as parameters, and breaking up the bandwidth uniformly, and inserting appropriate delays. Simple\_ra doesn’t actually use any of these, although if I add pulsar capability, it’s going to at least use on of the folder blocks, and one of the not-yet-written dedispersion blocks. – Marcus L. Principal Investigator Shirleys Bay Radio Astronomy Consortium > **[Live Draw HK Tercepat | Result HK | HK Pools | Live HK | HK Prize Hari Ini](https://www.sbrac.org/)** > > Temukan live draw hk tercepat melalui halaman hk pools yang resmi dan dapatkan result hk prize melalui live hk secara langsung di situs kami. ---
**Author:** ![Marcus\_DSLeech](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/74df32/32.png) [@Marcus\_DSLeech](https://www.ruby-forum.com/u/Marcus_DSLeech)\ **Post date:** [June 25, 2013, 10:43am UTC](https://www.ruby-forum.com/t/ra-blocks/235450/2 "2013-06-25T10:43:35Z")
Hi ! I tried this link and get Fehler beim Laden des Stylesheets: Beim Laden eines XSLT-Stylesheets ist ein Netzwerkfehler aufgetreten:[https://www.cgran.org/svnindex.xsl](https://www.cgran.org/svnindex.xsl) What does this mean ? – Volker Am 22.06.2013 04:12, schrieb Marcus D. Leech: ---
**Author:** ![Marcus\_DSLeech](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/74df32/32.png) [@Marcus\_DSLeech](https://www.ruby-forum.com/u/Marcus_DSLeech)\ **Post date:** [June 25, 2013, 2:54pm UTC](https://www.ruby-forum.com/t/ra-blocks/235450/3 "2013-06-25T14:54:49Z")
> The link I gave is for svn: svn co [http://www.cgran.org/svn/projects/gr-ra\_blocks](http://www.cgran.org/svn/projects/gr-ra_blocks) > > which > > it’s a decimator. > > o A “vector power” block (not sure what to actually call this). It > > > > the output vector. This is a GRC-derived hier block. > > sure how to integrate it into a hier block “cleanly”. > > * * * > > Discuss-gnuradio mailing list > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) – Marcus L. Principal Investigator Shirleys Bay Radio Astronomy Consortium > **[Live Draw HK Tercepat | Result HK | HK Pools | Live HK | HK Prize Hari Ini](https://www.sbrac.org)** > > Temukan live draw hk tercepat melalui halaman hk pools yang resmi dan dapatkan result hk prize melalui live hk secara langsung di situs kami.