diff --git a/antenna.html b/antenna.html index 575d7e6a65d60e0dc80d16c8b625043d12ce3bd9..855cccd59fd2b08bfcea7823172b27839a77c083 100644 --- a/antenna.html +++ b/antenna.html @@ -114,12 +114,12 @@ is designed to compensate for the gravitational deformations of the whole surfac <li>parabolic in fixed position (optimized for El=45°)</li> <li>parabolic in tracking (it adjusts according to the observed elevation position)</li> </ul> -<p>The shaped configuration is used for receivers in the Gregorian and BWG foci, while the parabolic configurations are used for the Primary focus systems.</p> +<p>The shaped configuration is used for receivers in the Gregorian and BWG foci, while the parabolic configurations are used for the primary focus systems.</p> </div> <div class="section" id="receivers"> <h1>Receivers<a class="headerlink" href="#receivers" title="Permalink to this headline">¶</a></h1> <ul class="simple"> -<li>The L-P band dual-frequency receiver was installed at the primary focus of the telescope, and therefore requires the parabolic configuration. It allows for simultaneous observations at L and P bands. The polarization type is linear but can be transformed to circular thanks to a hybrid converter.</li> +<li>The L-P band dual-frequency receiver was installed at the primary focus of the telescope, and therefore requires the parabolic configuration. It allows for simultaneous observations at L and P bands. The polarization type is linear but is also transformed to circular thanks to a hybrid converter.</li> <li>A single-feed C-high band receiver is installed at the Beam Wave Guide (BWG) focus of the telescope.</li> <li>A multi-feed K-band receiver is installed at the (secondary) Gregorian focus. Both C and K band receivers require the shaped configuration.</li> </ul> @@ -290,13 +290,16 @@ The observer can select the following configurations:</p> <div class="section" id="pulsar-digital-filter-bank-mark-3-pdfb3"> <h2>Pulsar Digital Filter Bank mark 3 (PDFB3)<a class="headerlink" href="#pulsar-digital-filter-bank-mark-3-pdfb3" title="Permalink to this headline">¶</a></h2> <p>This is an FX correlator developed by the Australia Telescope National Facility (ATNF) that performs full-Stokes observations. It allows for four inputs, each with a 1024 MHz maximum bandwidth and 8-bit sampling for a high dynamic range. The DFB3 is suitable for precise pulsar timing and searching. It allows for up to 8192 spectral channels in order to counter the effects of interstellar dispersion.</p> -<p>The main available configurations for pulsar observations are the following:</p> +<p>The available configurations for pulsar observations are the following:</p> <table border="1" class="docutils"> <colgroup> +<col width="9%" /> +<col width="13%" /> +<col width="15%" /> +<col width="22%" /> <col width="16%" /> -<col width="24%" /> -<col width="27%" /> -<col width="33%" /> +<col width="7%" /> +<col width="20%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Obs type</th> @@ -306,9 +309,18 @@ The observer can select the following configurations:</p> </th> <th class="head">Bandwidth (MHz)</th> <th class="head"><ol class="first last upperalpha simple" start="14"> -<li>frequency bins</li> +<li>frequency channels</li> </ol> </th> +<th class="head"><ol class="first last upperalpha simple" start="14"> +<li>polarizations</li> +</ol> +</th> +<th class="head"><ol class="first last upperalpha simple" start="14"> +<li>bits</li> +</ol> +</th> +<th class="head">Time sampling (sec)</th> </tr> </thead> <tbody valign="top"> @@ -316,74 +328,191 @@ The observer can select the following configurations:</p> <td>1024</td> <td>1024</td> <td>2048</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-odd"><td>folding</td> <td>1024</td> <td>1024</td> <td>1024</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-even"><td>folding</td> <td>1024</td> <td>1024</td> <td>512</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-odd"><td>folding</td> <td>1024</td> <td>512</td> <td>2048</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-even"><td>folding</td> <td>1024</td> <td>512</td> <td>1024</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-odd"><td>folding</td> <td>1024</td> <td>512</td> <td>512</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-even"><td>folding</td> <td>512</td> <td>1024</td> <td>1024</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-odd"><td>folding</td> <td>512</td> <td>512</td> -<td>1024</td> +<td>2048</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-even"><td>folding</td> <td>512</td> <td>512</td> -<td>512</td> +<td>1024</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-odd"><td>folding</td> <td>512</td> +<td>512</td> +<td>512</td> +<td> </td> +<td> </td> +<td> </td> +</tr> +<tr class="row-even"><td>folding</td> +<td>512</td> <td>256</td> <td>512</td> +<td> </td> +<td> </td> +<td> </td> +</tr> +<tr class="row-odd"><td>folding</td> +<td>512</td> +<td>128</td> +<td>2048</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-even"><td>folding</td> <td>256</td> <td>256</td> <td>2048</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-odd"><td>folding</td> <td>256</td> <td>256</td> +<td>1024(*)</td> +<td> </td> +<td> </td> +<td> </td> +</tr> +<tr class="row-even"><td>folding</td> +<td>256</td> +<td>64</td> +<td>2048</td> +<td> </td> +<td> </td> +<td> </td> +</tr> +<tr class="row-odd"><td>folding</td> +<td>256</td> +<td>64</td> <td>1024</td> +<td> </td> +<td> </td> +<td> </td> </tr> <tr class="row-even"><td>search</td> <td> </td> +<td>1024</td> +<td>512</td> +<td> </td> +<td> </td> +<td> </td> +</tr> +<tr class="row-odd"><td>search</td> +<td> </td> <td>512</td> <td>1024</td> +<td>1</td> +<td>1</td> +<td>0.000125</td> +</tr> +<tr class="row-even"><td>search</td> +<td> </td> +<td>512</td> +<td>1024</td> +<td>4</td> +<td>1</td> +<td>0.000512</td> </tr> <tr class="row-odd"><td>search</td> <td> </td> <td>512</td> +<td>1024</td> +<td>4</td> +<td>8</td> +<td>0.000512</td> +</tr> +<tr class="row-even"><td>search</td> +<td> </td> +<td>512</td> +<td>512</td> +<td>1</td> +<td>8</td> +<td>0.000064</td> +</tr> +<tr class="row-odd"><td>search</td> +<td> </td> +<td>512</td> +<td>512</td> +<td>4</td> +<td>8</td> +<td>0.000256</td> +</tr> +<tr class="row-even"><td>search</td> +<td> </td> +<td>512</td> <td>128</td> +<td> </td> +<td> </td> +<td> </td> </tr> </tbody> </table> +<p>(*) This configuration does not work with millisecond pulsars.</p> +<p>For search configurations, choosing 512 frequency channels works well except for polarization in the case of very fast-rotating pulsars. +With 1024 frequency channels, doing full Stokes works well only for slow pulsars; it is not recommended for millisecond pulsars even with just total intensity.</p> <p>Further details about the DFB can be found in the ATNF <a class="reference external" href="http://www.srt.inaf.it/media/uploads/astronomers/dfb.pdf">DFB manual</a>.</p> <p>At the SRT, DFB observations are piloted using the SEADAS software.</p> </div> @@ -401,7 +530,6 @@ Available configurations consist of:</p> <li>420 MHz bandwith with 1024 or 16384 channels</li> <li>1500 MHz bandwidth with 1024 or 16384 channels</li> </ul> -<p>The 420 MHz configurations are most suitable for the L-band receiver and the following RF filters: (3) 1350 - 1450 MHz or (5) 1625 - 1715 MHz, in order to avoid aliasing.</p> <p>SARDARA’s spectral resolution and sensitivity is defined by its full 1500 MHz bandwidth. However only 1200 MHz of the full 1500 MHz bandwidth is usable, since the 1200 MHz filter of the Total Power backend is being used as input to SARDARA.</p> <p>More detailed information on the SARDARA backend can be found here: <a class="reference external" href="https://www.worldscientific.com/doi/full/10.1142/S2251171718500046">SARDARA</a>.</p> </div> diff --git a/antenna.rst b/antenna.rst index 8e2d227538b16870fff80222da4a1dd829792938..6e9f079c3db4ffa404021a4e8a1902c762fa75bf 100644 --- a/antenna.rst +++ b/antenna.rst @@ -68,12 +68,12 @@ The observer can choose among three configurations: * parabolic in fixed position (optimized for El=45°) * parabolic in tracking (it adjusts according to the observed elevation position) -The shaped configuration is used for receivers in the Gregorian and BWG foci, while the parabolic configurations are used for the Primary focus systems. +The shaped configuration is used for receivers in the Gregorian and BWG foci, while the parabolic configurations are used for the primary focus systems. Receivers ========= -* The L-P band dual-frequency receiver was installed at the primary focus of the telescope, and therefore requires the parabolic configuration. It allows for simultaneous observations at L and P bands. The polarization type is linear but can be transformed to circular thanks to a hybrid converter. +* The L-P band dual-frequency receiver was installed at the primary focus of the telescope, and therefore requires the parabolic configuration. It allows for simultaneous observations at L and P bands. The polarization type is linear but is also transformed to circular thanks to a hybrid converter. * A single-feed C-high band receiver is installed at the Beam Wave Guide (BWG) focus of the telescope. @@ -86,7 +86,7 @@ equivalent flux density is the flux density of a radio source that doubles the s Band Frequency coverage (GHz) Feeds Polarization type Focal position Beam size Tsys (K) Gain (K/Jy) Sefd (Jy) ======== ========================= ======= ================= =============== ========= ========== =========== ========== P 0.30 -- 0.36 1 linear primary 56.2' [50-80] [0.45] 125 -L 1.3 -- 1.8 1 linear primary 12.6' 25-35 [0.47] 36 +L 1.3 -- 1.8 1 linear primary 12.6' 25-35 [0.47] 36 C-high 5.7 -- 7.7 1 circular beam waveguide 2.8' 32-37(*) 0.48 43(*) K 18 -- 26 7 circular gregorian 50"(**) 90(**) 0.44 138(**) ======== ========================= ======= ================= =============== ========= ========== =========== ========== @@ -171,11 +171,11 @@ Pulsar Digital Filter Bank mark 3 (PDFB3) This is an FX correlator developed by the Australia Telescope National Facility (ATNF) that performs full-Stokes observations. It allows for four inputs, each with a 1024 MHz maximum bandwidth and 8-bit sampling for a high dynamic range. The DFB3 is suitable for precise pulsar timing and searching. It allows for up to 8192 spectral channels in order to counter the effects of interstellar dispersion. -The main available configurations for pulsar observations are the following: +The available configurations for pulsar observations are the following: -========= ============= =============== ================== -Obs type N. time bins Bandwidth (MHz) N. frequency bins -========= ============= =============== ================== +========= ============= =============== ====================== ================ ======= ==================== +Obs type N. time bins Bandwidth (MHz) N. frequency channels N. polarizations N. bits Time sampling (sec) +========= ============= =============== ====================== ================ ======= ==================== folding 1024 1024 2048 folding 1024 1024 1024 folding 1024 1024 512 @@ -183,14 +183,30 @@ folding 1024 512 2048 folding 1024 512 1024 folding 1024 512 512 folding 512 1024 1024 +folding 512 512 2048 folding 512 512 1024 folding 512 512 512 folding 512 256 512 +folding 512 128 2048 folding 256 256 2048 -folding 256 256 1024 -search 512 1024 +folding 256 256 1024(*) +folding 256 64 2048 +folding 256 64 1024 +search 1024 512 +search 512 1024 1 1 0.000125 +search 512 1024 4 1 0.000512 +search 512 1024 4 8 0.000512 +search 512 512 1 8 0.000064 +search 512 512 4 8 0.000256 search 512 128 -========= ============= =============== ================== +========= ============= =============== ====================== ================ ======= ==================== + +(*) This configuration does not work with millisecond pulsars. + +For search configurations, choosing 512 frequency channels works well except for polarization in the case of very fast-rotating pulsars. +With 1024 frequency channels, doing full Stokes works well only for slow pulsars; it is not recommended for millisecond pulsars even with just total intensity. + + Further details about the DFB can be found in the ATNF `DFB manual <http://www.srt.inaf.it/media/uploads/astronomers/dfb.pdf>`_. @@ -214,8 +230,6 @@ Available configurations consist of: * 420 MHz bandwith with 1024 or 16384 channels * 1500 MHz bandwidth with 1024 or 16384 channels -The 420 MHz configurations are most suitable for the L-band receiver and the following RF filters: (3) 1350 - 1450 MHz or (5) 1625 - 1715 MHz, in order to avoid aliasing. - SARDARA's spectral resolution and sensitivity is defined by its full 1500 MHz bandwidth. However only 1200 MHz of the full 1500 MHz bandwidth is usable, since the 1200 MHz filter of the Total Power backend is being used as input to SARDARA. More detailed information on the SARDARA backend can be found here: `SARDARA <https://www.worldscientific.com/doi/full/10.1142/S2251171718500046>`_.