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information_for_astronomers:user_guide:signalpathsetup [2014/11/20 23:26]
bwinkel [Signal paths to the spectroscopic, VLBI, and pulsar backends]
information_for_astronomers:user_guide:signalpathsetup [2016/03/15 13:49]
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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 <​code>​SXXNNNZ</​code>​ <​code>​SXXNNNZ</​code>​
  
-where XX stands for the channel which one would like to change and NNN is a three-byte code for the mode. XX can be 01 to 16, or 99 (for all channels. Typical modes are:+where XX stands for the channel which one would like to change and NNN is a three-byte code for the mode. XX can be 01 to 16, or 99 (for all channels. ​**Note, that the MultiFiBa got a very slow processing unit, so sometimes it may take a while until the requested mode is set.** ​Typical modes are:
  
-^Mode^Channels^IF^Bandwidth^Attenuation-enabled^Comment+^Mode^Channels^IF ​name^IF range^Bandwidth^Attenuation^Comments^ 
-|097|8+16|VLBA IF|100 ​MHz|yes| | +^ ^ ^ ^[MHz]^[MHz]^enabled^ ^ 
-|185|8+16|VLBA IF|500 ​MHz|yes| | +|249|8+16|VLBA IF|700-800|100|yes| | 
-|128|8+16|Narrowband (SB)|100 ​MHz|yes| | +|185|8+16|VLBA IF|500-1000|500|yes| | 
-|134|8+16|Narrowband (SB)|50 ​MHz|yes|needs change in .front-files| +|128|8+16|Narrowband (SB)|100-200|100|yes| | 
-|128|1-7,​9-15|7-Beam IF|100 ​MHz|yes|exclusively for 21-cm 7-beam| +|134|8+16|Narrowband (SB)|150-200|50|yes|needs change in .front-files ​(ULO)
-|161|1-7,​9-15|7-Beam IF|300 ​MHz(*)|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| 
-|033|8+16|Optical|2/2.5 GHz|no|used for UBB/new K-band| +|161|1-7,​9-15|7-Beam IF|0-300|300(*)|yes|exclusively for 21-cm 7-beam| 
-|161|8+16|Baseband|1 GHz(+)|yes|mainly for VLBI and pulsars|+|033|8+16|Optical|0-2500|2500|no|used for UBB/new K-band| 
 +|161|8+16|Baseband|0-1000|1000(+)|yes|mainly for VLBI and pulsars|
 (*) 300 MHz from 7-Beam Rx/IF, MultiFiBa only applies 2.5 GHz lowpass\\ (*) 300 MHz from 7-Beam Rx/IF, MultiFiBa only applies 2.5 GHz lowpass\\
 (+) 1GHz from IF, MultiFiBa only applies 2.5 GHz lowpass (+) 1GHz from IF, MultiFiBa only applies 2.5 GHz lowpass
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-===== Wiring schemes for spectroscopy ​===== +===== MultiFiBa technical scheme ​===== 
-**OutdatedWill be updated soon.**+{{:​information_for_astronomers:​user_guide:​bsb_multifiba_rev.4_20141120.png?​1000|}}\\ 
 +{{:​information_for_astronomers:​user_guide:​bsb_multifiba_rev.4_20141120.pdf|}}
  
-=== XFFTS 100/500 MHz Bandwidths === 
  
-{{:​information_for_astronomers:​user_guide:​xffts_100_500mhz.png?​800|}} 
  
-=== XFFTS 2 GHz Bandwidth === 
- 
-{{:​information_for_astronomers:​user_guide:​xffts_2ghz.png?​800|}} 
- 
-=== AFFTS 7-Beam (100 MHz) === 
- 
-{{:​information_for_astronomers:​user_guide:​affts_7beam.png?​800|}} 
- 
-=== AFFTS channels 8 and 16 (100 MHz) === 
- 
-{{:​information_for_astronomers:​user_guide:​affts_8_16_100mhz.png?​800|}} 
- 
-===== Pictures ===== 
- 
-{{:​information_for_astronomers:​user_guide:​xffts_photo.png?​518|}}\\ 
-{{:​information_for_astronomers:​user_guide:​affts_photo.png?​556|}}\\ 
-{{:​information_for_astronomers:​user_guide:​multifiba1_rename.png?​768|}}\\ 
-{{:​information_for_astronomers:​user_guide:​multifiba2_rename.png?​576|}} 
information_for_astronomers/user_guide/signalpathsetup.txt · Last modified: 2017/01/25 20:24 by akraus