PDS_VERSION_ID = PDS3
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 80
OBJECT = TEXT
PUBLICATION_DATE = 1981-07-01
NOTE = "DSN Software Interface Specification for Radio
Science Medium Band Computer Compatible IDR.
Converted to digital format with minor editorial
corrections on 1996-11-13, 1998-06-04, and
1999-02-19."
END_OBJECT = TEXT
END
DOCUMENT 820-13; REV. A
DSN SYSTEM REQUIREMENTS
DETAILED INTERFACE DESIGN
----------------------------------------------------------------------
RSC-11-6
DSN INTERFACES RADIO SCIENCE
MEDIUM BAND COMPUTER COMPATIBLE IDR
(Insert this modular document in 820-13; Rev. A.)
EFFECTIVE DATE: 1 July 1981
Initial Release Date: 1 September 1980
Approved by:
s/B.J. Buckles (DSN S/E)
------------------------------
s/Jamie G. Brownlee (CDE)
------------------------------
s/Izeller E. Cureton (SCOE)
------------------------------
A. PURPOSE
This document defines and controls the format for the Radio Science
System Medium Bandwidth Computer compatible Intermediate Data Record (IDR).
[Radio Science IDRs should not be confused with the IDRs which are
generated at the GCF and may contain Radio Science data (See 820-13; Rev. A;
RSC-11-4).
B. REVISION AND CONTROL
Revisions or changes to the information herein may be initiated
according to the procedure in Section I of this document.
C. GENERAL INFORMATION AND DEFINITIONS
Radio Science Medium Band Computer compatible IDRs may be produced by
the Network Radio Science Subsystem (WRS) or by the DSS Radio Science
Subsystem (DRS) from Digital Recording Assembly (DRA) Original Data
Recordings (ODRs) recorded by the DRS. These IDRs are digital tapes.
Each tape will contain data for one spacecraft for one DSS per pass.
D. MEDIUM BANDWIDTH RADIO SCIENCE IDR TAPE FORMAT
The Medium Bandwidth Radio Science IDR tape format is shown in Figure
RSC-11-6-1. This format conforms to the American National Standards Institute
(ANSI) Standards for Phase Encoded (PE) tape, using wire tracks with a density
of 1600 b/in.
The data portion of the tape format is as described below and shown in
Figure RSC-11-6-2.
WORD 1
------
BIT
Time-Tag Validity Indicator
---------------------------
1 Indicates that time-tag data in Words 6 through 9 are
valid for this record [If time tag is invalid, the remaining
header information may be erroneous. Valid header
information (Words 1 through 27) occur on integer seconds,
as indicated by Time-Tag Validity.]
0 = Invalid
1 = Valid
Record Continuity Indicator
---------------------------
2 Indicates that this record is the first record of a
playback run
0 = Continuation
1 = First Record
Copy Source Error Indicator
---------------------------
3 Applies to IDR tape copies only; indicates that this
record was copied from an original record containing a
parity error
0 = No Source Error
1 = Source Error
Sample Count Validity Indicator
-------------------------------
4 Indicates that the sample count in Words 27 and 28 is
valid for this record
0 = Invalid
1 = Valid
ODA Tape Type Indicator
-----------------------
5 thru 8 Always set to 0000 to indicate medium band reduction
tape.
Tape Number
-----------
9 thru 16 Binary integer number; increments each time a tape is
completed for a given playback run
WORD 2
------
BIT
Record Number
-------------
1 thru 16 16-bit binary number
WORD 3
------
BIT
Record Length
-------------
1 thru 16 16-bit binary integer; indicates number of words in this
record; set to 2528 (decimal)
WORD 4
------
BIT
Spacecraft Number
-----------------
1 thru 8 Binary representation of spacecraft number (Refer to
module OPS-6-6, Tables OPS-6-6-9 and -10 of this
document)
Source Station
--------------
9 thru 16 Binary representation of DSS station number
WORD 5
------
BIT
DRA Tape Number
---------------
1 thru 16 16-bit binary number; tape number of DRA tape which is the
source for this reduction record
WORD 6
------
BIT
Data Time Tag
-------------
1 thru 4 Hundreds of Days; the data time tag is valid only when
Word 1, bit 1 is set to 1; the time tag in general will
not correspond to an exact integral second, but the first
data sample in the record will correspond to the exact
integral second which is closest to the time tag.
Data Time Tag (continued)
-------------------------
5 thru 8 Tens of Days
Data Time Tag (continued)
-------------------------
9 thru 12 Units of Days
Data Time Tag (continued)
-------------------------
13 thru 16 Tens of Hours
WORD 7
------
BIT
Data Time Tag (continued)
-------------------------
1 thru 4 Units of Hours
Data Time Tag (continued)
-------------------------
5 thru 8 Tens of Minutes
Data Time Tag (continued)
-------------------------
9 thru 12 Units of Minutes
Data Time Tag (continued)
-------------------------
13 thru 16 Tens of Seconds
WORD 8
------
BIT
Data Time Tag (continued)
-------------------------
1 thru 4 Units of Seconds
Data Time Tag (continued)
-------------------------
5 thru 16 First 12 bits of 20-bit binary number indicating number
of microseconds since start of second (MSB is bit 5)
WORD 9
------
BIT
Data Time Tag (continued)
-------------------------
1 thru 8 Last 8 bits of 20-bit binary number indicating number
of microseconds since start of second (LSB is bit 8)
9 thru 11 DRA Configuration/Status (DRA Input Selection)
----------------------------------------------
Should always be set to 001 for medium band data.
000 = Input #1
001 = Input #2
010 = Input #3
011 = Input #4
100 = Test Input
DRA Configuration/Status (DRA 1-PPS Status)
--------------------------------------------
12 0 = Present
1 = Absent
DRA Configuration/Status (DRA Clock Sync Status)
------------------------------------------------
13 0 = In-Sync (Normal)
1 = Out-of-Sync
DRA Configuration/Status (Real-Time Recording Monitor Source)
-------------------------------------------------------------
14 0 = Recorder A
1 = Recorder B
DRA Configuration/Status (DRA Microsecond Time Status)
------------------------------------------------------
15 0 = Normal
1 = Abnormal
DRA Configuration/Status (DRA Time-Track Sync)
----------------------------------------------
16 0 = Out-of-Sync
1 = In-Sync (Normal)
WORD 10
-------
BIT
Unused (Reserved) Bits
----------------------
1 thru 11 Undefined
Reduction Rate
--------------
12 thru 16 Rate at which data samples are transferred from DRA tape
to computer-compatible tape; the following are the only
codes valid for playback operations:
Playback Rate
(samples/sec) DRA Tape Speed (ips)
------------- --------------------
10000 50 K 7.5
01000 62.5K 7.5
00000 75 K 7.5
WORD 11
-------
BIT
Unused (Reserved) Bits
----------------------
1 thru 11 Undefined
Channel Sampling Rate
---------------------
12 thru 16 Sampling rate at which data were originally recorded
on the DRA tape; rate is the same for all four data
channels
Sampling Rate
(samples/sec) DRA Tape Speed (ips)
------------- --------------------
10000 50 K 7.5
01000 62.5K 7.5
00000 75 K 7.5
10001 100 K 15
01001 125 K 15
00001 150 K 15
10010 200 K 30
01010 250 K 30
00010 300 K 30
10011 400 K 60
01011 500 K 60
00011 600 K 60
10100 800 K 120
01100 1.0M 120
00100 1.2M 120
WORD 12
-------
BIT
Reduction Data Source
---------------------
1 Indicates data flow path for reduction data
0 = DRA Tape (Normal)
1 = DRA Bypass (Short-loop test only)
Reduction Decimation Ratio
--------------------------
2 thru 4 Factor by which data samples on the DRA tape are
decimated during playback/transfers to this tape record
111 = 1 (no decimation)
110 = 2
101 = 3
100 = 4
011 = 5
010 = 6
001 = 7
000 = 8
1 PPS Track Selection
---------------------
5 Indicates which track on the DRA tape is used for the
start-of-second reference
0 = Track 16
1 = Track 21
Time Track Selection
--------------------
6 Indicates which track on DRA tape is used for time-of-day
reference
0 = Track 22
1 = Track 23
Reduction Channel Selection
---------------------------
7 and 8 Indicates which originally recorded medium-bandwidth
input channel is selected for playback
00 = Channel 1
01 = Channel 2
10 = Channel 3
11 = Channel 4
Input Block Size Register
-------------------------
9 thru 16 Number of samples in 1 second of reduced data expressed
as a negative two's complement binary number.
WORD 13
-------
BIT
Input Block Size Register (Cont.)
---------------------------------
1 thru 16
WORDS 14 THRU 22
----------------
BIT
Unused (Reserved) Bits
----------------------
1 thru 16 Undefined
WORD 23
-------
BIT
Reduction Day of Year
---------------------
1 thru 9 Contains binary value of reduction day (GMT)
Unused (reserved) Bits
----------------------
10 thru 15 Undefined
Reduction Time of Day
---------------------
16 First bit (MSB) of 17-bit number representing number of
seconds since beginning of day
WORD 24
-------
BIT
Reduction Time of Day (Cont.)
-----------------------------
1 thru 16 Last 16 bits of 17-bit number representing number of
seconds since beginning of day
WORD 25
-------
BIT
Unused (Reserved) Bits
----------------------
1 thru 16 Undefined
WORD 26
-------
BIT
Unused (Reserved) Bits
----------------------
1 thru 8 Undefined
Status
------
9 1 = Input buffer overflow
0 = No overflow
Status (Cont.)
--------------
10 1 = 1 pps Out-of-Sync
0 = Not Out-of-Sync
Status (Cont.)
--------------
11 1 = Bit Slip
0 = No Out-of-Sync
Status (Cont.)
--------------
12-13 Spares
Decimation Counter Value
------------------------
14-16 111 = 1 (No decimation)
110 = 2
101 = 3
100 = 4
011 = 5
010 = 6
001 = 7
000 = 8
WORDS 27 AND 28
---------------
BIT
Sample Count
------------
1 thru 16 A 32-bit binary number which relates the first data
sample in this block to an integral second; valid only
when Word 1, bit 4 is set to 1; a number "n" stored in
this field indicates that the first sample in this
block was the nth sample after the start of the second
(at a decimation ratio of one -- see Word 12, bits 2
through 4); MSB is Word 27, bit 1 and LSB is Word 28,
bit 16.
NOTE
Refer to appendix for cases involving other decimation
ratios.
WORDS 29 THRU 2528
------------------
BIT
Data Samples
------------
1 thru 16 Each word contains two 8-bit data samples. MSBs of samples
are in bit 1 and bit 9; the "earlier" sample is in bits 1
through 8.
=============================================================================
---------- ---------------- -------------
|PREAMBLE |REFERENCE MODULE|POSTSCRIPT |
| 40 ZEROS| FIGURE 2 | 1 ONE |
| FOLLOWED|OF THIS DOCUMENT| FOLLOWED |
| BY 1 ONE| | BY 40 ZEROS|
---------- ---------------- -------------
| |
| |
| ----------------------------------
| |
| |
-------------- ------ ------ ------ ------ ------ --//-- ------ ------ ----
| PHASE | | 1st | | 2nd | | | | Nth | END|
| ENCODER |RECORD| DATA |RECORD| DATA |RECORD| |RECORD| DATA | OF |
|IDENTIFICATION| GAP |RECORD| GAP |RECORD| GAP | | GAP |RECORD|FILE|
| BURST | | | | | | | | | |
-------------- ------ ------ ------ ------ ------ --//-- ------ ------ ----
Figure RSC-11-6-1. Medium Bandwidth Radio Science Computer
Compatible Tape Format Conforming to ANSI Standards.
=============================================================================
BIT
-----------------------------------------------
|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
WORD 01 | V| C| E| S| 0 0 0 0| TAPE NO. |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
02 | RECORD NUMBER |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
03 | RECORD LENGTH |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
04 | SPACECRAFT ID | SOURCE STATION |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
05 | DRA TAPE NO. |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
06 | DAY (100s)| DAY (10s) |DAY (UNITS)| HR (10s) |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
07 | HR (UNITS)| MIN (10s) |MIN (UNITS)| SEC (10s) |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
08 |SEC (UNITS)| MICROSECONDS |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
09 | MICROSECONDS (contd) | CONFIGURATION |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
10 | UNDEFINED |REDUCT RATE|
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
11 | UNDEFINED |SAMPLE RATE|
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
12 | REDUCTION SOURCE | INPUT BLK SIZE REG |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
13 | INPUT BLOCK SIZE REGISTER (Cont.) |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
14 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
15 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
16 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
17 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
18 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
19 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
20 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
21 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
22 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
23 | REDUCTION DAY | UNDEFINED |TM|
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
24 | REDUCTION TIME OF DAY |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
25 | UNDEFINED |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
26 | UNDEFINED | STATUS |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
27 | SAMPLE COUNT |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
28 | SAMPLE COUNT (Cont.) |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
29 | DATA SAMPLES |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
30 | DATA SAMPLES |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
31 | DATA SAMPLES |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
/ /
/ /
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
2528 | DATA SAMPLES |
|--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|
-----------------------------------------------
Figure RSC-11-6-2. Medium (Bandwidth) Record Format
=============================================================================
APPENDIX A
MEDIUM BAND IDR RECORDS
The medium band converter hardware inputs data to the computer through
two channels, a control/monitor channel, and a data channel. The
control/monitor channel input contains time of day and status. It appears in
the record in Words 6 through 13. The data channel input contains A/D
converter values and a header. It appears in the record in Words 25 through
28. The header on the data channel contains 8 bytes of auxiliary information
that are inserted into the data stream when the number of data samples
indicated by the block size register has been input to the computer. The ODA
software sets the block size register to equal the sample rate of the recorder
at playback speed. If the record sample rate was 300K samples/second, the
playback rate is 75K samples/second. Validity flags are set when an input
occurs on either the control/monitor channel or the data channel. The data
header validity flag is set when an input occurs on the data channel (every
75K samples of input data) and the time validity flag is set every 300K
samples of input data. A control/monitor channel input sets bit 1 of Word 1
of the medium bandwidth record. The data channel header input sets bit 4 or
Word 1.
The decimation ratio is the factor by which the data samples on the DRA
tape are decimated during IDR production. A decimation ratio of one indicates
that every recorded sample is input to the computer. A decimation ratio of 3
indicates that every third sample is input to the computer.
The sample count in the ODA medium band IDR is the count of the number
of data samples (on the DRA tape) that have occurred since the last tape 1
pps. It indicates the data sample that is to be associated with the time of
the record.
Figure 1 shows the monitor/control and data channel inputs for a
decimation ratio 1. The DRS recorder is operated at 1/4 the rate at which
the data were recorded. The block size register is set to 75,000. This
causes a data channel header input once per second. Note that the 1 pps that
was recorded on the DRA tape when it was running at 300K samples, occurs every
4 seconds when the data is played back at 1.4 rate.
Figure 2 shows the two input channels when the decimation ratio is 3.
The data channel header is still input every 75,000 samples, but since every
third sample is being input, 225K recorded samples must pass before 75K are
input to the computer. Data channel header inputs now occur every 3 seconds.
The data channel validity flag is set every 12 seconds, which is every 3 tape
seconds.
Figure 3 shows the actual sample count for a decimation ratio of 3.
Every third sample is input to the computer, and causes the block size
counter increment. When the counter reaches 75,000, a data channel header
is input. The raw sample counter value input at the start of a tape 1 pps
period is 299997. Samples 299998 and 299999 were not yet counted when the
header was input. The ODA software adjusts the sample count to compensate
for the decimation ratio and to tag the first sample in the record as 1
rather than 0. It also subtracts the record sample rate from the compensated
sample count when a control/monitor input occurs. The records with valid time
in the header, therefore, have sample counts of 1, indicating that the first
sample corresponds to the time in the record. An illustration of this appears
below.
DECIMATION RATIO = 1 DECIMATION RATIO = 3
Record No. Sample Count Record No. Sample Count
---------- ------------ ---------- ------------
1 1 1 3
16 75001 16 225001
31 150001 31 150001
46 225001 46 75001
61 1 61 1
76 75001 76 225001
91 150001 91 150001
106 225001 106 75001
121 1 121 1
The sequence repeats throughout the entire IDR tape for records that do
not have missing or additional samples. Note that the first record on the
decimated tape has a sample count of 3 rather than 1. This occurs because
the first input occurs at the start of second rather than when the block size
count is exhausted, causing the raw sample count to be input as 299999 rather
than 299997.
A DRA tape can contain errors. These errors usually occur as parity
errors in the data samples. If an error occurs on the 1 pps track that
causes a spurious tape 1 pps, the sample counter will not contain the correct
count. The sample count returns to normal during the next second. This
situation is illustrated below at record 181.
Record No. Sample Count
---------- ------------
121 1
136 225001
151 150001
166 75001
181 164196
196 225001
211 150001
226 75001
241 1
256 225001
A DRA tape of poor quality may have "loss of sync" errors in addition to
the sample count reset errors. The data clock and the data lose
synchronization when this occurs, the data samples are lost. This type of
error is indicated by an offset in the sample count. In the example below,
records 451 through 481 illustrate this type of error. During the interval,
the sample count changed from 1 to 4. The data between record 451 and 481
are not usable because the time tag associated with the data samples is
unknown.
Record No. Sample Count
---------- ------------
361 1
376 225001
391 150001
406 48288
421 273288
436 225001
451 150001
466 29791
481 4
496 225004
511 150004
526 75004
541 4
When the sample count shifted from 1 to 4, it indicated that the time
tag of the first sample in the record shifted by 3 sample periods at the
record ratio, and is now 3 sample periods later in time than before. Another
way to consider it is that the first sample in the block would have been the
fourth sample had the sync loss not occurred.
=============================================================================
TAPE 1 PPS ----------------------------------------------------------------
| | | |
v v v v
-------------------------------------------------------------------
| | | | | | | | | | | | |
| | | | | | | | | | | | |
SAMPLE 0 75K 150K 225K 0 75K 150K 225K 0 75K 150K 225K 0
COUNT | | | | | | | | | | | | |
| | | | | | | | | | | | |
| | | | | | | | | | | | |
| | | | | | | | | | | | |
DATA CHANNEL | | | | | | | | | | | | |
HEADER INPUT v v v v v v v v v v v v v
AND VALIDITY | | | |
FLAG SET | | | |
| | | |
| | | |
MONITOR/CTRL | | | |
CHANNEL INPUT | | | |
AND VALIDITY v v v v
FLAG SET
DECIMATION RATIO = 1
RECORD SAMPLE RATE = 300K
PLAYBACK SAMPLE RATE = 75K
DATA CHANNEL HEADER INPUT EACH 75K RECORDED SAMPLES
SAMPLE COUNT RESET BY TAPE 1 PPS
Figure 1. Time and Data Channel Inputs Showing Sample Count
=============================================================================
TAPE 1 PPS ----------------------------------------------------------------
| | | | | |
v v v v v v
-------------------------------------------------------------------
| | | | | | | | | | | | | | | | | | | | |
| | | | | | |
SAMPLE 0 225K 150K 75K 0 225K 150K
COUNT | | | | | | |
| | | | | | |
| | | | | | |
DATA CHANNEL | | | | | | |
HEADER INPUT v v v v v v v
AND VALIDITY | |
FLAG SET | |
| |
| |
MONITOR/CTRL | |
CHANNEL INPUT | |
AND VALIDITY v v
FLAG SET
DECIMATION RATIO = 3
RECORD SAMPLE RATE = 300K
PLAYBACK SAMPLE RATE = 75K
DATA CHANNEL HEADER INPUT EACH 3x75K RECORDED SAMPLES
SAMPLE COUNT RESET BY TAPE 1 PPS
Figure 2. Time and Data Channel Inputs Showing Sample Count
=============================================================================
-- -- -- -- -- -- -- -- -- -- -- --
| | | | | | | | | | | | | | | | | | | | | |
-- -- -- -- -- -- -- -- -- -- --
DECIMATION 1 2 3 1 2 3 1 2 3 1 2
COUNT
SAMPLE 29991 29993 29995 29997 29999 1
COUNTER 29992 29994 29996 29998 0
BLOCK
SIZE 74998 74999 75000 1
COUNTER |
|
|
v
DATA CHANNEL HEADER
INPUT TO COMPUTER
RAW SAMPLE COUNT 299997
ODA S/W ADDS +4
ODA S/W SUBTRACTS -300000
-------
IDR SAMPLE COUNT 1
Figure 3. IDR Sample Count - Decimation Ratio = 3
=============================================================================
|