Commit 79977e6a authored by thomas.forbriger's avatar thomas.forbriger
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libdatrwxx [WP][DOC]: mseed binary data types and BTIME

parent 52df2ba8
......@@ -43,6 +43,8 @@
\par Quotations
- \subpage page_mseed_manual_quotations
- \subpage page_mseed_binary_types
- \subpage page_mseed_BTIME
- \subpage page_mseed_blockette8
- \subpage page_mseed_FixedSectionDataHeader
- \subpage page_mseed_blockette1000
......@@ -122,6 +124,11 @@
Suggests that each logical data record starts with a fixed header
\section sec_mseed_manual_page33 Page 33: BTIME data structure
- Defines \ref page_mseed_binary_types
- Defines \ref page_mseed_BTIME
\section sec_mseed_manual_page37 Page 37: [8] Telemetry Volume Identifier Blockette
......@@ -227,6 +234,81 @@
/* ====================================================================== */
/*! \page page_mseed_binary_types Binary data types
On page 33 of "SEED Reference Manual, Standard for the Exchange of
Earthquake Data, SEED Format Version 2.4, August, 2012":
Throughout this manual, we use some conventions to describe the sizes of fields in the SEED format. Here are the
binary data types used in data record contents:
Field type Number of bits Field description
UBYTE 8 Unsigned quantity
IBYTE 8 Two’s complement signed quantity
UWORD 16 Unsigned quantity
WORD 16 Two’s complement signed quantity
ULONG 32 Unsigned quantity
LONG 32 Two’s complement signed quantity
CHAR * n n*8 n characters, each 8 bits and each with a 7-bit ASCII character
(high bit always 0)
FLOAT 32 IEEE Floating point number
The IEEE floating point format consists of three stored components: a sign (+ or -), an exponent, and a fraction. In the
following description of the storage format these notations will be used.
s = sign e = biased exponent f = fraction
The sign is the sign of the fraction. Rather than storing the sign of the exponent a bias is added to the exponent, and the
biased exponent is stored.
s e f
bit positions 31 30:23 22:0
IEEE single precision values occupy one 32 bit word as shown above in 68000 byte order. Bits 0:22 store the 23 bit
fraction, bits 23:30 store the 8 bit exponent, and the high order bit 31 stores the sign bit. The 23 bit fraction combined
with the implicit leading bit provide 24 bits of precision in normalized numbers. The value of an IEEE single precision
floating point number is calculated as
-1s x 2(e-127) x 1.f
The byte order of a FLOAT is specified in the station identifier blockette [50].
/* ====================================================================== */
/*! \page page_mseed_BTIME BTIME structure
On page 33 of "SEED Reference Manual, Standard for the Exchange of
Earthquake Data, SEED Format Version 2.4, August, 2012":
Binary data types are used in the BTIME structure:
Field type Number of bits Field description
UWORD 16 Year (e.g., 1987)
UWORD 16 Day of Year (Jan 1 is 1)
UBYTE 8 Hours of day (0—23)
UBYTE 8 Minutes of day (0—59)
UBYTE 8 Seconds of day (0—59, 60 for leap seconds)
UBYTE 8 Unused for data (required for alignment)
UWORD 16 .0001 seconds (0—9999)
NOTE: The BTIME structure differs from the ASCII variable length TIME structure used in the control headers.
/* ====================================================================== */
/*! \page page_mseed_blockette8 [8] Telemetry Volume Identifier Blockette
On page 37 of "SEED Reference Manual, Standard for the Exchange of
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