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information_for_astronomers:user_guide:signalpathsetup [2014/11/21 11:10] bwinkel |
information_for_astronomers:user_guide:signalpathsetup [2017/01/25 20:24] (current) akraus |
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===== Signal paths to the spectroscopic, VLBI, and pulsar backends ===== | ===== Signal paths to the spectroscopic, VLBI, and pulsar backends ===== | ||
- | There are several IF chains going to the Faraday room (where the backends live), most importantly the VLBA and narrow-band (SB) IF. Furthermore, the 21-cm 7-feed system has its own IF; and some receivers provide a 2+ GHz IF over optical fibers. All IFs are usually used with different bandwidth setups and need different attenuation to bring the power to a level which is appropriate for the backend ADCs. This is done using the so-called **MultiFiBa**. | + | There are several IF chains going to the Faraday room (where the backends live), most importantly the VLBA and narrow-band (SB) IF. Furthermore, the 21-cm 7-feed system has its own IF; and some receivers provide a 2+ GHz IF over optical fibers. All IFs are usually used with different bandwidth setups and need different attenuation to bring the power to a level which is appropriate for the backend ADCs. This is done using the so-called **MultiFiBa**. |
The various IFs coming from the receivers are fed into the 16-channel MultiFiBa, which allows to apply several internal bandpass filters and attenuation. Channels 1-7 and 9-15 is almost exclusively used for the 21-cm 7-Beam system. All other receivers are attached to channels 8+16. For each channel the **mode** can be changed with the command | The various IFs coming from the receivers are fed into the 16-channel MultiFiBa, which allows to apply several internal bandpass filters and attenuation. Channels 1-7 and 9-15 is almost exclusively used for the 21-cm 7-Beam system. All other receivers are attached to channels 8+16. For each channel the **mode** can be changed with the command | ||
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^Mode^Channels^IF name^IF range^Bandwidth^Attenuation^Comments^ | ^Mode^Channels^IF name^IF range^Bandwidth^Attenuation^Comments^ | ||
^ ^ ^ ^[MHz]^[MHz]^enabled^ ^ | ^ ^ ^ ^[MHz]^[MHz]^enabled^ ^ | ||
- | |249|8+16|VLBA IF|700-800|100|yes| | | + | |216|8+16|VLBA IF|700-800|100|yes| | |
|185|8+16|VLBA IF|500-1000|500|yes| | | |185|8+16|VLBA IF|500-1000|500|yes| | | ||
- | |128|8+16|Narrowband (SB)|100-200|100|yes| | | + | |000|8+16|Narrowband (SB)|100-200|100|yes| | |
- | |134|8+16|Narrowband (SB)|150-200|50|yes|needs change in .front-files (ULO)| | + | |006|8+16|Narrowband (SB)|150-200|50|yes|needs change in .front-files (ULO)| |
|128|1-7,9-15|7-Beam IF|100-200|100|yes|exclusively for 21-cm 7-beam| | |128|1-7,9-15|7-Beam IF|100-200|100|yes|exclusively for 21-cm 7-beam| | ||
|161|1-7,9-15|7-Beam IF|0-300|300(*)|yes|exclusively for 21-cm 7-beam| | |161|1-7,9-15|7-Beam IF|0-300|300(*)|yes|exclusively for 21-cm 7-beam| |