Mcrds data format
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MCRDS Data Format. May 3, 2006. File Type Header. Data file type 32 byte string (“Data-MCRDS”) terminated with null character ‘\0’. Characters after termination undefined. 2 bytes unsigned short representing year 1 byte unsigned character representing subyear version 5 bytes reserved.

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MCRDS Data Format

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Mcrds data format

MCRDS Data Format

May 3, 2006


File type header

File Type Header

  • Data file type

    • 32 byte string (“Data-MCRDS”) terminated with null character ‘\0’. Characters after termination undefined.

    • 2 bytes unsigned short representing year

    • 1 byte unsigned character representing subyear version

    • 5 bytes reserved


Data header block

Data Header Block

struct HeaderBlock

{

int dataType;

double sampFreq;% 120 MHz

int prfCount;% PRF = 1/(prfCount*1e-7)

int numAve;% # of hardware integrations (i.e. coherent averages)

int rxAtten[8][2][4];

int rxBlank[8][1][4];

char calModeEn;% always false

char numWaveforms;

char pad[2];% reserved

int calNumOfPnts;% not used during data collection

double calStartFreq;% not used during data collection

double calStopFreq;% not used during data collection

double calDelay;% not used during data collection

double calDuration;% not used during data collection

};


Fields of interest rx mode

Fields of interest: Rx mode

  • rxAtten and rxBlank

    • Each of the eight receivers are loaded with 4 different modes. The modes for each receiver are independent of one another.

      • E.g. mode 1 for receiver 2 can be different than mode 1 for receiver 3.

    • A mode is defined by the settings of the two digital step attenuators and the blank delay line selection.

      • The receiver has a single blanking switch, but two different control lines that can be selected.

    • During any given pulse period, all receivers must be in the same mode number.

      • I.e. the radar does not allow receiver 2 to be in mode 1 while receiver 3 is in mode 2.


Fields of interest waveforms

Fields of interest: Waveforms

  • The radar system transmits a set of waveforms defined by the radar operator.

  • The radar loads this sequence of waveforms into the system. For example:

    • 3 us linear FM chirp, radar mode 0

      • Receiver gain settings are set to allow capture of the surface echo and both transmit amplifiers are enabled.

    • 10 us linear FM chirp, radar mode 1

      • Receiver gain settings set to maximize dynamic range while keeping the lowest noise figure possible and satisfying our A2D dithering req. Transmit antenna one enabled.

    • 10 us linear FM chirp, radar mode 2

      • Receiver gain settings set to maximize dynamic range while keeping the lowest noise figure possible and satisfying our A2D dithering req. Transmit antenna five enabled.

  • When the radar is enabled, each of the waveforms and radar modes is run in sequence.

    • E.g. With three waveforms the effective PRF of an individual waveform becomes PRF/3


Waveform headers part of data header block

Waveform Headers (part of data header block)

  • struct WaveformHeaderBlock

  • {

  • double startFreq;% 20 MHz (USB mixing with 120 MHz LO to 140 MHz)

  • double stopFreq; % 40 MHz (USB mixing with 120 MHz LO to 160 MHz)

  • double pulseDuration;% arbitrary (but most likely 1 us, 3 us or 10 us)

  • double calFreq;% 0 (disabled during data collection)

  • double calDelay;% unused

  • double calDuration;% unused

  • char bandSelect;% 0 for 150 MHz band, 1 for 450 MHz band

  • char zeroPiMod;% 0 for no modulation, 1 for zero-pi modulation

  • char txMult;% unused

  • char rxMode;% 0, 1, 2, or 3

  • char txAmpEn[2];% [0] control tx amp 0, [1] controls tx amp 1

  • char pad[2];

  • int mod0Count;% transmitter blanking control line

  • int mod1Count;% transmit amplifier blanking control line

  • int numSam[4];% number of samples for each DAQ to capture (4 daqs, each with 2 channels)

  • int sampleDelayCount[4];% delay for DAQ begins capturing

  • char recordEn[8];% per channel record enable

  • int recordDelay[8];% per channel recording window start sample

  • int recordNumSam[8];% per channel recording number of samples

  • int blankDelay0Count;% receiver blank control line 0

  • int blankDelay1Count;% receiver blank control line 1

  • };

  • COUNTS ARE DEFINED AS 10 MHz clock cycles (0.1 us) and are relative to the AWG trigger. The transmit waveform is delayed by 1 us. Therefore “zero-time” has a count of 10.


Awg block

AWG Block

  • For predistortion and non-ideal linear FM chirps

    • We are not using this data block for May 06.


Data block

Data Block

  • 4 byte integer for data type (data type is 2 for data blocks)

  • 8 bytes for computer time stamp

    • 4 bytes for seconds since epoch (Jan 1, 1970)

    • 4 bytes for microseconds

  • 8 bytes for radar time (free-running 10 MHz counter on the radar board)

    • Used to precisely synchronize to the 1 pps provided by the Wallop’s Flight Facility group.

  • 4 bytes for DAQ errors

    • 1 byte per DAQ

    • Byte is zero when there is no error

    • Most common error is a FIFO error which causes a reset of the FIFOs and a few dropped records

  • Binary data follows (2 byte unsigned samples)

    • 12 bit DAQ, 64 integrations = 18 bits

    • 2 bits dropped = 16 bit sample


Overview

Overview

File Type

Data Header

Data Block 0

Datatype (=2)

Waveform 0

Sample 0

Computer Time

Data Block 1

Waveform 1

Sample 1

Radar Time

Data Block 2

Waveform 2

Sample 2

DAQ Error Bytes

DAQ 0

DAQ 1

DAQ 2


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