High-Bit-Rate Work Tape File Format

Record size: 2 x 16 bites headers followed by frames of data; variable-length format

Frame size: 288 bytes (3 subframes of 96 bytes each)

File constitution:
Each WTH file consists of double (occasionally single-)16-byte headers, and successive 288-byte frames (3 subframes of 96 bytes each) to the end of the file. A WTH file contains only the A17 High-Bit-Rate data from the Passive Listening Mode of LSPE.

Header Format

Bytes	Information (16-bit integers)
1-2	4 to identify High-Bit-Rate Work tape
3-4	active staion code 5 for Apollo 17 stations.
5-6	number of active stations (=1)
7-8	original 9-track tape ID number (6001 through 6336)
9-10	year
11-14 and first 4 bits of byte 15	time of the year of the first data in msec, 36-bit integer
Remaining bits of byte 15 and byte 16	not used

Data Format: In each subframe

*1 Long word consists of 32 bits
Long Word	Bits	Data
1	0	a flag bit indicating usage of computer-generated time code
1	1-31	31msb of 35-bit time of the year in ms
2	0-3	4lsb of 35-bit time of the year in ms
2	4-7	ALSEP tracking station ID
2	8-10	ALSEP package ID =5
2	11-15	bit synchronizer status: bit 11=search; bit 12=verify; bit 13=confirm; bit 14=lock; bit 15=input level
2	16-31	original 7-track record number (first subframe only)
3-22	0-29	20 LSPE data words
3-22	30-31	not used
23-24	0-31	not used

LSPE Data Word Allocation

Each LSPE data word consists of 30 bits of data, and it is included in Long Words 3-22 in the WTH files. The data allocation of the LSPE words is described in LSEP Data Word Allocation.