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operations:documentation.ivs.mark5mode
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operations:documentation.ivs.mark5mode [2016/04/15 10:27] Nick Ham Added info on Mark5 data recording mode & rate |
operations:documentation.ivs.mark5mode [2018/02/27 05:19] Warren Hankey |
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| + | ===Mode Modern=== | ||
| + | for Mark5B machines, | ||
| + | mode? now returns mk5b_mode=ext,<bitmask>,,<sampling> | ||
| + | |||
| + | sampling is rate (1 or 2 GB/s) times twice (Nyquist) bandwidth of 2,4,8,16 MHz gives 4,8,16,32 or 64 | ||
| + | |||
| + | bitstream mask 0xffffffff is 11111111 11111111 11111111 11111111 so all 32 bitstreams are taken. There are sixteen channels so two values per channel sign (positive/negative 1/0), and amplitude (high/low 1/0) give 32 bitstreams (2-bit samples). Bitstream mask 0x55555555 is 01010101 01010101 01010101 01010101 means unsigned, just amplitude for 16 channels (1-bit samples). | ||
| + | |||
| + | data rate is (2 x bandwidth) x (16 channels) | ||
| + | e.g. ks experiment 64 x 16 | ||
| + | |||
| For VSI recording, 1-bit sampling and 8 MHz bandwidths (e.g. R1 and R4 experiments): | For VSI recording, 1-bit sampling and 8 MHz bandwidths (e.g. R1 and R4 experiments): | ||
| <code>mk5=mode=ext:0x55555555:2</code> | <code>mk5=mode=ext:0x55555555:2</code> | ||
| Line 13: | Line 24: | ||
| * ''/mk5/!mode? 0 : ext : 0xffffffff : 2 : 2 ;'' for the 2nd and 4th R1/R4 experiments each month; | * ''/mk5/!mode? 0 : ext : 0xffffffff : 2 : 2 ;'' for the 2nd and 4th R1/R4 experiments each month; | ||
| * ''/mk5/!mode? 0 : ext : 0x55555555 : 2 : 2 ;'' for all other R1 and R4 experiments; | * ''/mk5/!mode? 0 : ext : 0x55555555 : 2 : 2 ;'' for all other R1 and R4 experiments; | ||
| - | * ''/mk5/!mode? 0 : ext : 0x55555555 : 4 : 2 ;'' for APSG, CRF, OHIG and T2 experiments; and | + | * ''/mk5/!mode? 0 : ext : 0x55555555 : 4 : 2 ;'' for APSG, CRF, OHIG and T2 experiments; and |
| * ''/mk5/!mode? 0 : ext : 0xffffffff : 1 : 1 ;'' for AUST experiments. | * ''/mk5/!mode? 0 : ext : 0xffffffff : 1 : 1 ;'' for AUST experiments. | ||
| ===== <return code> ===== | ===== <return code> ===== | ||
| - | When ''mk5=mode?'' returns successfully, ''<return code>'' will be ''0'', anything else ought to be investigated. Descriptions for what the other possible return codes indicate may be found on Page 2 of [[http://www.haystack.mit.edu/tech/vlbi/mark5/docs/Mark%205B%20DIM%20command%20set%20Rev%201.12.pdf|the Mark5B command set pdf (Rev 1.12)]]. | + | When ''mk5=mode?'' returns successfully, ''<return code>'' will be ''0'', anything else ought to be investigated. Descriptions for what the other possible return codes indicate may be found on Page 2 of [[http://www.haystack.mit.edu/tech/vlbi/mark5/docs/Mark%205B%20DIM%20command%20set%20Rev%201.12.pdf|the Mark5B command set pdf (Rev 1.12)]]. |
| ===== <data source> ===== | ===== <data source> ===== | ||
| Line 31: | Line 42: | ||
| Recall that the conversion to binary from the hexadeximal number: | Recall that the conversion to binary from the hexadeximal number: | ||
| - | * ''5'' is ''0101'' (?which indicates one-bit sampling?); and | + | * ''5'' is ''0101'' (which indicates one-bit sampling); and |
| - | * ''f'' is ''1111'' (?which indicates two-bit sampling?). | + | * ''f'' is ''1111'' (which indicates two-bit sampling). |
| - | One-bit sampling uses the sign of recorded voltages when recording, two-bit sampling partitions the interval of possible voltages up in to ''4'' pieces to obtain sign and magnitude components. | + | One-bit sampling uses the sign of recorded voltages when recording, two-bit sampling partitions the interval of possible voltages up in to ''4'' pieces to obtain sign and magnitude components. |
| Possible values for ''<bit-stream mask>'' are: | Possible values for ''<bit-stream mask>'' are: | ||
| Line 40: | Line 51: | ||
| * ''0xffffffff''. | * ''0xffffffff''. | ||
| - | <note>(need to note which way around the channels are ordered).</note> | + | <note>Channels 1-8 are X-band upper sideband (USB) from BBcs 1-8, channels 9 and 10 are the X-band LSB channels of BBCs 1 and 8, and channels 11-16 are S-band USB BBCs 9-14.</note> |
| ===== <decimation ratio> ===== | ===== <decimation ratio> ===== | ||
| Line 47: | Line 58: | ||
| Possible values for ''<decimation ratio>'' are: | Possible values for ''<decimation ratio>'' are: | ||
| * ''1'' which indicates we are keeping all of the data (16 MHz bandwidth); | * ''1'' which indicates we are keeping all of the data (16 MHz bandwidth); | ||
| - | * ''2'' which indicates we are keeping one half of the data (8 MHz bandwidth); | + | * ''2'' which indicates we are keeping one half of the data (8 MHz bandwidth); |
| * ''4'' which indicates we are keeping one quarter of the data (4 MHz bandwidth); and | * ''4'' which indicates we are keeping one quarter of the data (4 MHz bandwidth); and | ||
| * ''8'' which indicates we are keeping one eighth of the data (2 MHz bandwidth). | * ''8'' which indicates we are keeping one eighth of the data (2 MHz bandwidth). | ||
| Line 59: | Line 70: | ||
| <note>FPDP stands for Front-Panel Data Port.</note> | <note>FPDP stands for Front-Panel Data Port.</note> | ||
| + | |||
| + | ====== Sampling Rate ====== | ||
| + | Recall that the nyquist rate is the minimum rate at which a signal can be sampled without introducing errors, which is twice the highest frequency present in a signal. Consequently, the __sampling rate__ is double the maximum bandwidth per channel (which the decimation ratio determines). | ||
| ====== Mark5 Data Recording Rate ====== | ====== Mark5 Data Recording Rate ====== | ||
/home/www/auscope/opswiki/data/pages/operations/documentation.ivs.mark5mode.txt · Last modified: 2018/02/27 05:19 by Warren Hankey
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