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." 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 =============================================================================