The options are detailed below:

**Center Frequency:**This is the frequency on which the individual board is centered. This can either be the rest frequency or observed frequency of your lines. (A description is given below of the possible velocity corrections which can be made to the entered frequencies.)**Bandwidth:**The available range in bandwidths is 50.0 - 0.781 MHz. Bandwidth is only available as a binary fraction of 50.0MHz. That is, you can choose from 50.0, 25.0, 12.5, 6.25, 3.125, 1.562, 0.781, or 0.195 MHz.**Sampling level:**Your data can be sampled with either 3-level, 3-level interleaved, or 9-level sampling. 9-level operation achieves 98% of the signal-to-noise of analog correlation, whereas 3-level sampling achieves 81%. One advantage of 9-level sampling is to limit the effects of RFI (usually) to just a few channels.**You cannot use 9-level sampling with a 50-MHz bandpass.**If you wish to use the 50-MHz bandpass you must use 3-level interleaved sampling.**Polarization:**For each board you have the option of having either A, B, A & B, or full Stokes polarizations. If you use either only A or only B polarization and 3-level interleaved sampling, you can have access to the entire 4096 channels on each board. If you choose to split a board into both A & B polarizations, or increase the sampling levels, you naturally cut down on the the number of available channels.**No. of Channels (Lags) Used:**The total number of channels available on each board is 4096. This number can only be used, though, if you are using 3-level (interleaved) sampling. Increasing your sampling to 9-level cuts the total number of channels available in half (to 2048). A complete listing of the options is given in Table 3. Note that the smaller your number of channels, the smaller (in size) your data file will be for a given record dump. Your options for the number of channels to use are: 4096 (only with one polarization and 3-level interleaved sampling), 2048 (available for the 3-level A and B polarization set-up or the 9-level sampling with one polarization), 1024 (available for all set-ups), 512, 256, 126, 64, 32, or 16 channels.

Sampling |
Max BW |
Pol/sbc |
lags/sbc |
Resolution |

per sbc |
at 1420MHz |
|||

9-level | 25MHz | 1 | 2048 | 2.6 km/s |

9-level | 25MHz | 2 | 1024 | 5.2 km/s |

3-level | 25MHz | 2 | 2048 | 2.6 km/s |

3-level interleaved | 50MHz | 1 | 4096 | 2.6 km/s |

3-level interleaved | 50MHz | 2 | 2048 | 5.2 km/s |

3-level Stokes | 25MHz | - | 2048 | 2.6 km/s |