atm digital receiver (echotek card)


Linux config:
Ryan seals thesis (.pdf)
source locations:
Notes/bugs echotek online gui
    all buffers get written to disc.

12nov09: sine wave to check freq, timing
30mar06: echotek config error caused IQ imbalance.
sep05: glitches (out of order ipps) in the data.
sep05: baud transitions show power overshoots

Intro: (top)

 The echotek  card is used to  filter and sample the aeronomy signals. It plugs into the pci bus. The  30 MHz IF is sampled at 80 MHz and then reduced to 5 or 10 MHz bandwidth. The card returns 16 bit complex samples. The card  operation is:
  • The sampling is normally triggered by the transmitter rf pulse (from the sps).
  • BurstCount samples are acquired and shipped to the cpu. This value is user programmable. It needs to be a multiple of 4096 bytes.
  • A linux driver runs a dma chain that tells the echotek where to put the data. There are two buffers that the driver loads.
  • The data taking software grabs a completed buffer from the kernel. It selects a portion of the input data and moves it to one of two output buffers. A tx section, height section, and noise section are selected. This selection is needed so the i/o rate to disc is manageable. The number of output buffers is currently set at two (but it can be increased).
  • A separate thread takes the full output buffers and writes them to disc.
  • The data files contain an ascii  primary header followed by a set of records (or tables). Each record contains an ascii header followed by a number of ipps of data. This is typically 100 ipps. At 10 millisecs per ipp each record holds 1 second worth of data. Files are filled with an integral number of records until the  2 Gb limit. New files are created automatically. Data should be continuous across files.

  • 12nov09: sine wave checking freq/timing

        A sine wave was injected into the echotek card to check the freq and timing.


    Plots showing the results of the test (.ps) (.pdf):

        The data is plotted in black,  the red plot is a  16010 Hz sinewave computed with the amplitude of the measure data and the phase of the measured sinewave at the start of  ipp0.


    Glitches (out of order ipps) in the data.  (top)

         Out of order records (glitches) were found in test data taken 11aug05. The glitches appeared to be aligned with the 1 second records.
    see:  11aug05: out of order records in the 11aug05 test data.
        More test data was taken on 07sep05. This data did not show any of  the jumps seen in the 11aug05 data.
    see: 07sep05: test data shows no out of order records.
    The differences in the echotek card configuration for the two data sets was: The IF configuration was also different on the two days. On 11aug05 the sampled signal was centered at 434 MHz. On 07sep05 it was centered at 430 MHz.  Since the transmitter samples were always  at 430MHz, the 11aug05 had the tx samples offset by 4MHz from DC.  This made the tx samples look different, but should not have had any affect on the records being out of order.

    sep05: baud transitions show power overshoots

            The transmitter is phase coded with a barker and  random shift register code (clp). On  07sep05 the atm digital receiver recorded  power and coded long pulse  ipps. The data was output as 10 MHz complex samples. The bandwidth was 7.5 MHz. The plots show the transmitter response to these transitions (.ps) (.pdf) : processing: x101/050907/

    linux software config

  • 05apr06:
  • logfile are not being written?,
  • ntpd not running system clock is 5 seconds fast.
  • /etc/cron.daily is running slocate every morning at 3:01.

  • History:

  • 05apr06: ntpd has not been  running. system clock is  fast by 5 seconds.
  • 05apr06: cron.daily has been running slocate at 3:01 every morning. This should probably be removed.

  • Source locations (21jan13)

        Source code for the software is located on the daeron computer:

    svn repos:
    svn list file:///home/svn/radarSVN/trunk                               

    working area

    cd /usr/local/radarTk
    svn info
    Path: .
    URL: file:///home/svn/radarSVN/branches
    Repository Root: file:///home/svn/radarSVN
    Repository UUID: 7d53ecaf-a2f4-0310-94ec-ef7151cc01ef
    Revision: 136
    Node Kind: directory
    Schedule: normal
    Last Changed Author: rseal
    Last Changed Rev: 136
    Last Changed Date: 2006-12-20 17:41:53 -0400 (Wed, 20 Dec 2006)

    Note: this was checked out of branches, not from the trunk.

    runtime programs and their links:

    Notes/Bugs online software:


    Configure gui:  ..src/echoConfig/src

    RadarTk: class definitions: ../RadarTk/*.h

    All buffers get written to disc instead of just clp buffers.

        Occasionally the echotek code writes all buffers to disc rather than just the clp buffers.

    The code to figure this is:

    so the code path is:
    My guess is that the codedLongPulse* is setting isValid =0 because of what it thinks the txWindow is.

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