FS-1052: Appendix A

FS-1052: Appendix A

APPENDIX A

39-TONE PARALLEL MODE

10. GENERAL.

10.1 Scope. This appendix describes the 39-tone parallel mode.

10.2 Applicability. This appendix is a nonmandatory part of FED-STD-1052; however, when the optional 39-tone parallel mode is used, it shall be implemented in accordance with this appendix.

20. APPLICABLE DOCUMENTS. See section 2.

30. DEFINITIONS. See section 3.

40. GENERAL REQUIREMENTS. The mode specified herein uses 39 orthogonal subcarrier tones in the audio frequency band with quadrature differential phase-shift keying (QDPSK) modulation for bit-synchronous data transmission. In the transmit direction, this mode (see Fig. 7);

a. accepts UNKNOWN serial binary data at its line-side data input port,
b. performs forward error correction (FEC) encoding and interleaving, and
c. converts the resulting coded serial bit stream into QDPSK data tones at the modulator output port.

The modulation rate of the modulator output is constant for all data rates. In-band diversity of varying degrees is used at data rates below 1200 bits per second (b/s). A means is provided for synchronization of the signal element and interleaved data block timing. A 40th unmodulated tone is used for correcting frequency offsets introduced by doppler shift or radio equipment instability. In a like manner, the receive direction;

a. accepts QDPSK data tones at its demodulator input port,
b. converts them back into the transmitted coded serial bit stream,
c. performs deinterleaving and FEC decoding, and
d. makes the resulting serial binary data stream available at its line-side output port.

Figure 7. Transmit direction functional diagram


50. DETAILED REQUIREMENTS.

50.1 Characteristics. In this section, detailed requirements are given for the waveform characteristics for which knowledge is needed to achieve over-the-air interoperability. These characteristics are error-correction coding, interleaving, synchronization, modulator output signal, in-band time/frequency diversity, and asynchronous data operation.

50.2 Error-correcting coding. All UNKNOWN input data shall have redundant bits added to it, prior to modulation, for the purpose of correcting errors introduced by the transmission medium. The added bits shall be computed by a shortened Reed-Solomon (15,11) block code, whose generator polynomial is:

g(x) = x4 + a13x3 + a6x2 + a3x + a10;

where a is a nonzero element of the Galois field (GF)(24) formed as the field of polynomials over GF(2) modulo x4 + x + 1.

For input signaling rates of 2400 b/s, the code shall be shortened to (14,10). Otherwise, the code shall be shortened to (7,3).

50.3 Interleaving. The mode shall perform block interleaving for the purpose of providing time separation between contiguous symbols of a code word. Selectable interleaving degrees for the data rates as shown in Table XIII shall be provided. For a data signaling rate of 2400 b/s, the selection shall consist of eight degrees. At data signaling rates below 2400 b/s, four degrees for each bit rate shall be provided as shown in Table XIII. The input data stream shall be loaded into the interleaver buffer as described by figures 8 and 9.

TABLE XIII. Selectable interleaving degrees

Data rate (b/s)
75
150
300
600
1200
2400

Interleaving

degree
1
1
1
1
1
1
1
4
9
17
33
63
9
72
12
25
47
99
189
18
144
36
81
153
297
567
27
288

Figure 8. Data flow through encoder and interleaver for an interleaver containing an even


number of code words

Figure 9. Data flow through encoder and interleaver for an interleaver containing an odd number


of code words

50.4 Synchronization. A means shall be provided whereby the receive demodulator process achieves time alignment with both signal element and code-word timing. Frame synchronization shall be acquired within 680 milliseconds (ms). The transmit sequence of events is shown on Figure 10.

50.4.1 Preamble. Prior to the transmission of data, a three-part preamble shall be transmitted. Part one shall last for 14 signal-element periods and consist of four equal-amplitude unmodulated data tones of 787.5, 1462.5, 2137.5, and 2812.5 hertz (Hz). Part two shall last for 8 signal-element periods and consist of three modulated data tones of 1125.0, 1800.0, and 2475.0 Hz. The three data tones of part two shall be advanced 180 degrees at the boundary of each data signal element. Part three shall last for one signal-element period and consist of all 39 data tones plus the doppler correction tone. This last part establishes the starting phase reference for subsequent signal-element periods. During all parts of the preamble, the transmitted level of the composite signals shall have a root-mean-square (rms) value within ±1 decibel (dB) of the rms value of the modulator output (39-tone) levels occurring during subsequent data transmission. The tone phases at the onset of each part of the preamble, along with their normalized amplitudes, shall be in accordance with Table XIV.

50.4.2 Extended preamble. To improve the probability of synchronization and signal presence detection in low signal-to-noise ratio situations, the ability to select an extended preamble shall be provided. Part one of the extended preamble shall last for 58 signal-element periods, part two shall last for 27 signal-element periods, and part three shall last for 12 signal-element periods. In parts one and two, the data tones shall be as described in the nonextended preamble given above. In part three, the phase of each data tone shall be set at the onset of each signal element to the phase that it had at the onset of the first signal element in this part.

NOTE: When operating with the extended preamble, the minimum doppler correction shall be ±20 Hz and frame synchronization shall be acquired within 2.5 seconds (s).

50.4.3 Data block synchronization. A set of interleaved code words is known as a super block. Block synchronization (framing) is the process whereby a receiving demodulator locates super block boundaries. This synchronization process must occur before proper deinterleaving and decoding can commence. Framing shall be established and maintained by periodically inserting into the encoded unknown data bit stream a known pseudorandom sequence. The required sequence is defined by the primitive polynomial,

f(x) = x9 + x7 + x6 + x4 + 1,

when used in the feedback shift register configuration shown in Figure 11. The first insertion of the block framing sequence shall start on the first signal element following the synchronization preamble. Upon transmission of the last bit of the sequence, the first bit of the first super block shall be transmitted without interruption. Thereafter, the framing sequence shall be inserted each time the number of super blocks specified in Table XV has been transmitted. Upon transmission of the last bit of the framing sequence, transmission of data bits shall resume without interruption. The number of framing bits to be transmitted per insertion varies with data rate and interleaving degree, and is specified in Table XV. However, the final bit of the framing sequence shall always be the first SPACE bit which follows a contiguous block of nine MARK bits. Equivalently, the final sequence bit shall be the bit generated by the shift register when its present state is 111111111 (binary) or 511 (decimal).

Figure 10. Transmit sequence of events


TABLE XIV. Tone set application, amplitude, and phase

Preamble
part
number
Tone freq (Hz) Function Normalized amplitude Initial phase (degrees)
1 787.50 Data tone 3 3 0.0
1 1462.50 Data tone 15 3 103.7
1 2137.50 Data tone 27 3 103.7
1 2812.50 Data tone 39 3 0.0
2 1125.00 Data tone 9 4 0.0
2 1800.00 Data tone 21 4 90.0
2 2475.00 Data tone 33 4 0.0
3 393.75 Doppler 2 0.0
3 675.00 Data tone 1 1 0.0
3 731.25 Data tone 2 1 5.6
3 787.50 Data tone 3 1 19.7
3 843.75 Data tone 4 1 42.2
3 900.00 Data tone 5 1 73.1
3 956.25 Data tone 6 1 115.3
3 1012.50 Data tone 7 1 165.9
3 1068.75 Data tone 8 1 225.0
3 1125.00 Data tone 9 1 295.3
3 1181.25 Data tone 10 1 14.1
3 1237.50 Data tone 11 1 101.3
3 1293.75 Data tone 12 1 199.7
3 1350.00 Data tone 13 1 303.8
3 1406.25 Data tone 14 1 59.1
3 1462.50 Data tone 15 1 185.6
3 1518.75 Data tone 16 1 317.8
3 1575.00 Data tone 17 1 101.3
3 1631.25 Data tone 18 1 253.1
3 1687.50 Data tone 19 1 56.3
3 1743.75 Data tone 20 1 225.0
3 1800.00 Data tone 21 1 45.0
3 1856.25 Data tone 22 1 236.3
3 1912.50 Data tone 23 1 73.1
3 1968.75 Data tone 24 1 281.3
3 2025.00 Data tone 25 1 137.8
3 2081.25 Data tone 26 1 5.6
3 2137.50 Data tone 27 1 239.1
3 2193.75 Data tone 28 1 123.8
3 2250.00 Data tone 29 1 19.7
3 2306.25 Data tone 30 1 281.3
3 2362.50 Data tone 31 1 194.1
3 2418.75 Data tone 32 1 115.3
3 2475.00 Data tone 33 1 45.0
3 2531.25 Data tone 34 1 345.9
3 2587.50 Data tone 35 1 295.3
3 2643.75 Data tone 36 1 253.1
3 2700.00 Data tone 37 1 222.2
3 2756.25 Data tone 38 1 199.7
3 2812.50 Data tone 39 1 185.6

Figure 11. Framing sequence feedback shift register generator


50.5 Modulator output signal. The modulator output shall contain 39-QDPSK data tones (see Table XVI). The 39 data tones shall be simultaneously keyed to produce a signal-element interval of 22.5 ms for each data tone. The composite modulator output shall have a constant modulation rate of 44.44 baud (Bd) for all standard input data signaling rates from 75 to 2400 b/s. At input signaling rates less than 2400 b/s, information carried on data tones 1 through 7 shall also be carried on data tones 33 through 39. The modulator shall also provide the required special preamble tone combinations used to initiate synchronization and doppler correction. During data transmission, the unmodulated doppler correction tone shall be 6 dB (±1 dB) higher than the normal level of any data tone. All tone frequencies shall maintain an accuracy of ±0.05 Hz. At the onset of each signal element, every data tone shall experience a phase change relative to its phase at the onset of the previous signal element. The modulator shall partition the bit stream to be transmitted into 2-bit symbols (dibits) and map them into a phase change of the appropriate data tone according to Table XVII.

50.6 In-band diversity. Two selectable methods of in-band diversity for data rates of 75-600 b/s shall be incorporated in each modem as follows: a modern method containing both time and frequency diversity, and a frequency-only diversity method for backward compatibility with older modems. The requirements given for these methods in the following subparagraphs apply to diversities of order d, where d = 1200/(data signaling rate).

50.6.1 Time/frequency diversity. Disregarding the redundant data carried on data tones 33 through 39, 64 bits, equally partitioned into d data words, shall be transmitted during each 22.5-ms signal element. Each data word and its d-1 copies shall be transmitted on 32/d unique data tones in d different signal elements. If data word i is being transmitted in a given signal element, the other data words that are to be transmitted in the same signal element are given by i - k(16/d), where k ranges from 1 through d-1 (see Table XVIII).

50.6.2 Frequency diversity. In-band diversity shall be characterized by transmitting a data word and its (d-l) copies in one signal element (e.g., 22.5-ms time interval). This characterization is according to the tone/bit assignments shown in Table XIX.

TABLE XV. Framing sequence insertion intervals and lengths

Data rate (b/s) Interleaving degree Insertion interval Sequence length (bits)
(super blocks) (bits)
75 1 567 15876 252
75 4 234 26208 416
75 12 75 25200 400
75 36 16 16128 256
150 1 576 16128 256
150 9 100 25200 400
150 25 36 25200 400
150 81 8 18144 288
300 1 567 15876 252
300 17 54 25704 408
300 47 18 23688 376
300 153 4 17136 272
600 1 567 15876 252
600 33 30 27720 440
600 99 10 27720 440
600 297 2 16632 264
1200 1 567 15876 252
1200 63 14 24696 392
1200 189 6 31752 504
1200 567 1 15876 252
2400 1 144 8064 256
2400 9 16 8064 256
2400 18 12 12096 384
2400 27 9 13608 432
2400 36 7 14112 448
2400 72 3 12096 384
2400 144 1 8064 256
2400 288 1 16128 512
NOTE: Insertion interval does not include framing sequence bits.

TABLE XVI. Data-tone frequencies and bit locations

Tone freq (Hz) Function
Bit Locations
2400 b/s
1200 b/s
393.75 Continuous Doppler
675.00 Data tone 1 1 2 1 2
731.25 Data tone 2 3 4 3 4
787.50 Data tone 3 5 6 5 6
843.75 Data tone 4 7 8 7 8
900.00 Data tone 5 9 10 9 10
956.25 Data tone 6 11 12 11 12
1012.50 Data tone 7 13 14 13 14
1068.75 Data tone 8 15 16 15 16
1125.00 Data tone 9 17 18 17 18
1181.25 Data tone 10 19 20 19 20
1237.50 Data tone 11 21 22 21 22
1293.75 Data tone 12 23 24 23 24
1350.00 Data tone 13 25 26 25 26
1406.25 Data tone 14 27 28 27 28
1462.50 Data tone 15 29 30 29 30
1518.75 Data tone 16 31 32 31 32
1575.00 Data tone 17 33 34 33 34
1631.25 Data tone 18 35 36 35 36
1687.50 Data tone 19 37 38 37 38
1743.75 Data tone 20 39 40 39 40
1800.00 Data tone 21 41 42 41 42
1856.25 Data tone 22 43 44 43 44
1912.50 Data tone 23 45 46 45 46
1968.75 Data tone 24 47 48 47 48
2025.00 Data tone 25 49 50 49 50
2081.25 Data tone 26 51 52 51 52
2137.50 Data tone 27 53 54 53 54
2193.75 Data tone 28 55 56 55 56
2250.00 Data tone 29 57 58 57 58
2306.25 Data tone 30 59 60 59 60
2362.50 Data tone 31 61 62 61 62
2418.75 Data tone 32 63 64 63 64
2475.00 Data tone 33 65 66 1 2
2531.25 Data tone 34 67 68 3 4
2587.50 Data tone 35 69 70 5 6
2643.75 Data tone 36 71 72 7 8
2700.00 Data tone 37 73 74 9 10
2756.25 Data tone 38 75 76 11 12
2812.50 Data tone 39 77 78 13 14

TABLE XVII. Modulation characteristics of the 39-tone HF modem

Logic sense of dibits
Phase change

(degrees)

Later bit Earlier bit
MARK (1) SPACE (0) +45
SPACE (0) SPACE (0) +135
SPACE (0) MARK (1) +225
MARK (1) MARK (1) +315

50.7 Asynchronous data operation. In addition to bit-synchronous data transmission, an asynchronous mode shall also be supported. When operating in the asynchronous mode, the modulator shall accept source data in asynchronous start/stop character format, convert it to bit synchronous data, and replace the start, stop, and parity bits with SPACE bits prior to FEC encoding. Conversely, after FEC decoding, the demodulator shall restore the converted bit synchronous data back into asynchronous format and re-generate the start, stop, and parity bits before placing the characters in the output data stream. Otherwise, the mode operates as specified in pars. 50.1 through 50.6 above.

50.7.1 Character length. A means shall be provided whereby the modulator will accept, and the demodulator will generate, any of the data characters shown in Table XX.

50.7.2 Data signaling rate constraint. A means shall be provided whereby the selected data signaling rate of the modem is constrained to not exceed the nominal bit rate of the data input source.

50.7.3 Data-rate adjustment. A means shall be provided whereby differences between data signaling rates of the data input source and the modem are accommodated with no loss of data or introduction of extraneous data in the demodulated output.

50.7.3.1 Input data source rate greater than modem rate. The modem shall maintain a control path to the data source for the purpose of stopping the flow of data into the modulator. When the modem senses that continued flow of input data will result in data loss, it shall cause the data source to suspend the transfer of data. Upon sensing that the threat of data loss has passed, the modem shall allow the transfer of data to resume.

TABLE XVIII. In-band time/frequency diversity

Tone no. 600 b/s Data word 300 b/s Data word 150 b/s Data word 75 b/s Data word
1  1     2  1     2  1     2  1     2 i
2  3     4  3     4  3     4 i  3     4
3  5     6  5     6  5     6  1     2 i-1
4  7     8  7     8 i  7     8  3     4
5  9    10  9    10  1     2  1     2 i-2
6 11    12 11    12  3     4 i-2  3     4
7 13    14 13    14  5     6  1     2 i-3
8 15    16 i 15    16  7     8  3     4
9 17    18  1     2  1     2  1     2 i-4
10 19    20  3     4  3     4 i-4  3     4
11 21    22  5     6  5     6  1     2 i-5
12 23    24  7     8 i-4  7     8  3     4
13 25    26  9    10  1     2  1     2 i-6
14 27    28 11    12  3     4 i-6  3     4
15 29    30 13    14  5     6  1     2 i-7
16 31    32 15    16  7     8  3     4
17  1     2  1     2  1     2  1     2 i-8
18  3     4  3     4  3     4 i-8  3     4
19  5     6  5     6  5     6  1     2 i-9
20  7     8  7     8 i-8  7     8  3     4
21  9    10  9    10  1     2  1     2 i-10
22  11   12  11   12  3     4 i-10  3     4
23  13   14  13   14  5     6  1     2 i-11
24  15   16 i-8  15   16  7     8  3     4
25  17   18   1    2  1     2  1     2 i-12
26  19   20   3    4  3     4 i-12  3     4
27  21   22   5    6  5     6  1     2 i-13
28  23   24   7    8 i-12  7     8  3     4
29  25   26   9   10  1     2  1     2 i-14
30  27   28  11   12  3     4 i-14  3     4
31  29   30  13   14  5     6  1     2 i-15
32  31   32  15   16  7     8  3     4
33   1    2   1    2  1     2  1     2 i
34   3    4   3    4  3     4 i  3     4
35   5    6   5    6  5     6  1     2 i-1
36   7    8 i   7    8 i  7     8  3     4
37   9   10   9   10  1     2  1     2 i-2
38  11   12  11   12  3     4 i-2  3     4
39  13   14  13   14  5     6  1     2 i-3

TABLE XIX. In-band frequency diversity

Tone
freq (Hz)
Function
 600 b/s 300 b/s 150 b/s 75 b/s
   393.75   Continuous doppler
   675.00   Data tone  1  1     2  1     2 1     2 1     2
   731.25   Data tone  2  3     4  3     4 3     4 3     4
   787.50   Data tone  3  5     6  5     6 5     6 1     2
   843.75   Data tone  4  7     8  7     8 7     8 3     4
   900.00   Data tone  5  9    10  9    10 1     2 1     2
   956.25   Data tone  6 11    12 11    12 3     4 3     4
  1012.50   Data tone  7 13    14 13    14 5     6 1     2
  1068.75   Data tone  8 15    16 15    16 7     8 3     4
  1125.00   Data tone  9 17    18  1     2 1     2 1     2
  1181.25   Data tone 10 19    20  3     4 3     4 3     4
  1237.50   Data tone 11 21    22  5     6 5     6 1     2
  1293.75   Data tone 12 23    24  7     8 7     8 3     4
  1350.00   Data tone 13 25    26  9    10 1     2 1     2
  1406.25   Data tone 14 27    28 11    12 3     4 3     4
  1462.50   Data tone 15 29    30 13    14 5     6 1     2
  1518.75   Data tone 16 31    32 15    16 7     8 3     4
  1575.00   Data tone 17  1     2  1     2 1     2 1     2
  1631.25   Data tone 18  3     4  3     4 3     4 3     4
  1687.50   Data tone 19  5     6  5     6 5     6 1     2
  1743.75   Data tone 20  7     8  7     8 7     8 3     4
  1800.00   Data tone 21  9    10  9    10 1     2 1     2
  1856.25   Data tone 22 11    12 11    12 3     4 3     4
  1912.50   Data tone 23 13    14 13    14 5     6 1     2
  1968.75   Data tone 24 15    16 15    16 7     8 3     4
  2025.00   Data tone 25 17    18  1     2 1     2 1     2
  2081.25   Data tone 26 19    20  3     4 3     4 3     4
  2137.50   Data tone 27 21    22  5     6 5     6 1     2
  2193.75   Data tone 28 23    24  7     8 7     8 3     4
  2250.00   Data tone 29 25    26  9    10 1     2 1     2
  2306.25   Data tone 30 27    28 11    12 3     4 3     4
  2362.50   Data tone 31 29    30 13    14 5     6 1     2
  2418.75   Data tone 32 31    32 15    16 7     8 3     4
  2475.00   Data tone 33  1     2  1     2 1     2 1     2
  2531.25   Data tone 34  3     4  3     4 3     4 3     4
  2587.50   Data tone 35  5     6  5     6 5     6 1     2
  2643.75   Data tone 36  7     8  7     8 7     8 3     4
  2700.00   Data tone 37  9    10  9    10 1     2 1     2
  2756.25   Data tone 38 11    12 11    12 3     4 3     4
  2812.50   Data tone 39 13    14 13    14 5     6 1     2

TABLE XX. Asynchronous character set

Nr. of bits

Character bit designation and location
1
2
3
4
5
6
7
8
9
10
11
12
7 Start Data Data Data Data Data Stop
8 Start Data Data Data Data Data +Par Stop
8 Start Data Data Data Data Data -Par Stop
8 Start Data Data Data Data Data Stop Stop
8 Start Data Data Data Data Data Data Stop
9 Start Data Data Data Data Data +Par Stop Stop
9 Start Data Data Data Data Data -Par Stop Stop
9 Start Data Data Data Data Data Data +Par Stop
9 Start Data Data Data Data Data Data -Par Stop
9 Start Data Data Data Data Data Data Stop Stop
9 Start Data Data Data Data Data Data Data Stop
10 Start Data Data Data Data Data Data +Par Stop Stop
10 Start Data Data Data Data Data Data -Par Stop Stop
10 Start Data Data Data Data Data Data Data +Par Stop
10 Start Data Data Data Data Data Data Data -Par Stop
10 Start Data Data Data Data Data Data Data Stop Stop
10 Start Data Data Data Data Data Data Data Data Stop
11 Start Data Data Data Data Data Data Data +Par Stop Stop
11 Start Data Data Data Data Data Data Data -Par Stop Stop
11 Start Data Data Data Data Data Data Data Data +Par Stop
11 Start Data Data Data Data Data Data Data Data -Par Stop
11 Start Data Data Data Data Data Data Data Data Stop Stop
12 Start Data Data Data Data Data Data Data Data +Par Stop Stop
12 Start Data Data Data Data Data Data Data Data -Par Stop Stop
NOTE: +Par = Positive parity, -Par = Negative parity

50.7.3.2 Input data source rate less than modem rate. When the modem senses that it is about to exhaust its supply of source data, it shall insert a special "null" character into the source data bit stream prior to encoding. The null character shall be formed by making each of its bits a SPACE, and the start, stop, and parity bits a MARK. The demodulator shall recognize this bit pattern as a null character, and discard it from its data output.

50.7.4 End-of-message (EOM) indication. Upon reception of the source's final data character, the modulator shall insert a series of EOM characters into the source data bit stream prior to encoding. The EOM character shall be formed by making each of its bits a MARK. The number of EOM characters inserted shall range from a minimum of ten to the number greater than ten required to fill a super block. The demodulator shall use the arrival of the EOM characters to terminate its data output.

50.7.5 Asynchronous mode interleaving and block framing. The degree of interleaving and the framing sequence length used in the asynchronous mode vary with data signaling rate and character length. With each data rate and character length, four selectable interleaving degrees shall be provided as shown in tables XXI thru XXVI, along with the corresponding framing sequence length.

50.7.6 Bit packing. An integral number of data characters shall be transmitted between framing sequence transmissions. Therefore, the number of bits encoded will not always equal the number of bits received from the data source. In such cases, the modulator shall insert into the source data a number of fill bits equal to the difference between the number of bits encoded and the number of bits received (see tables XXI thru XXVI). The fill bits shall be located in the bit stream so that they are the first bits encoded, thereby permitting the remainder of the data transmission to carry an integral number of data characters.

60. PERFORMANCE REQUIREMENTS. The minimum performance of the 39-tone mode employing soft-decision decoding and maximum interleaving, as measured using a baseband HF simulator patterned after the Watterson Model for channel simulation, shall be as shown in table XXVII.

TABLE XXI. 75-b/s asynchronous operational parameters

Data rate (b/s) Char length (bits) Interleaver degree Super blocks Nr. of bits encoded Nr. of source bits Fill bits Seq nr. length (bits)
75 7 1 567 6804 6804 0 252
75 7 5 189 11340 11340 0 420
75 7 12 84 12096 12096 0 448
75 7 35 18 7560 7560 0 280
75 8 1 576 6912 6912 0 256
75 8 4 234 11232 11232 0 416
75 8 12 75 10800 10800 0 400
75 8 36 16 6912 6912 0 256
75 9 1 567 6804 6804 0 252
75 9 4 252 12096 12096 0 448
75 9 12 84 12096 12096 0 448
75 9 36 16 6912 6912 0 256
75 10 1 585 7020 7020 0 260
75 10 4 242 11616 11610 6 416
75 10 12 75 10800 10800 0 400
75 10 35 18 7560 7560 0 280
75 11 1 594 7128 7128 0 264
75 11 4 260 12480 12474 6 448
75 11 11 99 13068 13068 0 484
75 11 33 18 7128 7128 0 264
75 12 1 567 6804 6804 0 252
75 12 4 261 12528 12528 0 464
75 12 12 84 12096 12096 0 448
75 12 36 16 6912 6912 0 256

TABLE XXII. 150-b/s asynchronous operational parameters

Data rate (b/s) Char length (bits) Interleaver degree Super blocks Nr. of bits encoded Nr. of source bits Fill bits Seq nr. length (bits)
150 7 1 567 6804 6804 0 252
150 7 9 112 12096 12096 0 448
150 7 27 35 11340 11340 0 420
150 7 81 7 6804 6804 0 252
150 8 1 576 6912 6912 0 256
150 8 9 100 10800 10800 0 400
150 8 25 36 10800 10800 0 400
150 8 81 8 7776 7776 0 288
150 9 1 567 6804 6804 0 252
150 9 9 112 12096 12096 0 448
150 9 25 38 11400 11394 6 408
150 9 81 7 6804 6804 0 252
150 10 1 585 7020 7020 0 260
150 10 9 110 11880 11880 0 440
150 10 25 36 10800 10800 0 400
150 10 75 9 8100 8100 0 300
150 11 1 594 7128 7128 0 264
150 11 9 110 11880 11880` 0 440
150 11 27 33 10692 10692 0 396
150 11 77 9 8316 8316 0 308
150 12 1 567 6804 6804 0 252
150 12 9 110 11880 11880 0 440
150 12 27 33 10692 10692 0 396
150 12 81 7 6804 6804 0 252

TABLE XXIII. 300-b/s asynchronous operational parameters

Data rate (b/s) Char length (bits) Interleaver degree Super blocks Nr. of bits encoded Nr. of source bits Fill bits Seq nr. length (bits)
300 7 1 567 6804 6804 0 252
300 7 15 63 11340 11340 0 420
300 7 49 18 10584 10584 0 392
300 7 145 5 8700 8694 6 308
300 8 1 576 6912 6912 0 256
300 8 17 54 11016 11016 0 408
300 8 47 18 10152 10152 0 376
300 8 153 4 7344 7344 0 272
300 9 1 567 6804 6804 0 252
300 9 17 54 11016 11016 0 408
300 9 47 18 10152 10152 0 376
300 9 153 4 7344 7344 0 272
300 10 1 585 7020 7020 0 260
300 10 17 49 9996 9990 6 356
300 10 45 22 11880 11880 0 440
300 10 153 5 9180 9180 0 340
300 11 1 594 7128 7128 0 264
300 11 19 43 9804 9801 3 356
300 11 45 22 11880 11880 0 440
300 11 161 4 7728 7722 6 272
300 12 1 567 6804 6804 0 252
300 12 17 54 11016 11016 0 408
300 12 49 18 10584 10584 0 392
300 12 153 4 7344 7344 0 272

TABLE XXIV. 600-b/s asynchronous operational parameters

Data rate (b/s) Char length (bits) Interleaver degree Super blocks Nr. of bits encoded Nr. of source bits Fill bits Seq nr. length (bits)
600 7 1 567 6804 6804 0 252
600 7 35 27 11340 11340 0 420
600 7 105 9 11340 11340 0 420
600 7 315 2 7560 7560 0 280
600 8 1 576 6912 6912 0 256
600 8 33 30 11880 11880 0 440
600 8 99 10 11880 11880 0 440
600 8 297 2 7128 7128 0 264
600 9 1 567 6804 6804 0 252
600 9 33 30 11880 11880 0 440
600 9 99 10 11880 11880 0 440
600 9 297 2 7128 7128 0 264
600 10 1 585 7020 7020 0 260
600 10 33 30 11880 11880 0 440
600 10 99 10 11880 11880 0 440
600 10 315 2 7560 7560 0 280
600 11 1 594 7128 7128 0 264
600 11 33 30 11880 11880 0 440
600 11 99 10 11880 11880 0 440
600 11 297 2 7128 7128 0 264
600 12 1 567 6804 6804 0 252
600 12 33 30 11880 11880 0 440
600 12 99 10 11880 11880 0 440
600 12 297 2 7128 7128 0 264

TABLE XXV. 1200-b/s asynchronous operational parameters

Data rate (b/s) Char length (bits) Interleaver degree Super blocks Nr. of bits encoded Nr. of source bits Fill bits Seq nr. length (bits)
1200 7 1 567 6804 6804 0 252
1200 7 63 15 11340 11340 0 420
1200 7 189 6 13608 13608 0 504
1200 7 567 1 6804 6804 0 252
1200 8 1 576 6912 6912 0 256
1200 8 63 14 10584 10584 0 392
1200 8 189 6 13608 13608 0 504
1200 8 576 1 6912 6912 0 256
1200 9 1 567 6804 6804 0 252
1200 9 63 15 11340 11340 0 420
1200 9 189 6 13608 13608 0 504
1200 9 567 1 6804 6804 0 252
1200 10 1 585 7020 7020 0 260
1200 10 63 15 11340 11340 0 420
1200 10 195 6 14040 14040 0 520
1200 10 585 1 7020 7020 0 260
1200 11 1 594 7128 7128 0 264
1200 11 65 16 12480 12474 6 448
1200 11 203 5 12180 12177 3 444
1200 11 619 1 7428 7425 3 268
1200 12 1 567 6804 6804 0 252
1200 12 63 15 11340 11340 0 420
1200 12 189 6 13608 13608 0 504
1200 12 567 1 6804 6804 0 252

TABLE XXVI. 2400-b/s asynchronous operational parameters

Data rate (b/s) Char length (bits) Interleaver degree Super blocks Nr. of bits encoded Nr. of source bits Fill bits Seq nr. length (bits)
2400 7 1 145 5800 5796 4 252
2400 7 36 7 10080 10080 0 448
2400 7 73 3 8760 8757 3 385
2400 7 282 1 11280 11277 3 497
2400 8 1 144 5760 5760 0 256
2400 8 36 7 10080 10080 0 448
2400 8 72 3 8640 8640 0 384
2400 8 288 1 11520 11520 0 512
2400 9 1 144 5760 5760 0 256
2400 9 36 7 10080 10080 0 448
2400 9 72 3 8640 8640 0 384
2400 9 288 1 11520 11520 0 512
2400 10 1 144 5760 5760 0 256
2400 10 36 7 10080 10080 0 448
2400 10 72 3 8640 8640 0 384
2400 10 288 1 11520 11520 0 512
2400 11 1 151 6040 6039 1 267
2400 11 33 9 11880 11880 0 528
2400 11 71 3 8520 8514 6 370
2400 11 297 1 11880 11880 0 528
2400 12 1 144 5760 5760 0 256
2400 12 36 7 10080 10080 0 448
2400 12 72 3 8640 8640 0 384
2400 12 288 1 11520 11520 0 512

TABLE XXVII. Probability of bit error vs signal-to-noise ratio

Signal-to-noise ratio (dB in 3-kHz bandwidth)
Probability of bit error
2400 b/s 1200 b/s
5 8.6 × 10-2 6.4 × 10-2
10 3.5 × 10-2 4.4 × 10-3
15 1.0 × 10-2 3.4 × 10-4
20 1.0 × 10-3 9.0 × 10-6
30 1.8 × 10-4 2.7 × 10-6
Signal-to-noise ratio (dB in 3-kHz bandwidth)
Probability of bit error
300 b/s 75 b/s
0 1.8 × 10-2 4.4 × 10-4
2 6.4 × 10-3 5.0 × 10-5
4 1.0 × 10-3 1.0 × 10-6
6 5.0 × 10-5 1.0 × 10-6
8 1.5 × 10-6 1.0 × 10-6
NOTE: Two independent equal average-power Rayleigh fading paths, with 2-Hz fading bandwidth and 2-ms multipath spread.