The different types of RDS frame require different repetitions rates to be effective.
There are repetition rate recommendations in the pre 2009 RDS standards but now this has developed more freedom of choice for repetition rates. Typical transmission proportions of groups:
| Group Type | Features | Typical Proportions |
|---|---|---|
| 0A or 0B | PI, PS, PTY, TP, AF, TA, DI, M/S | 40% |
| 1A or 1B | PI, PTY, TP, PIN | 10% |
| 2A or 2B | PI, PTY, TP, RT | 25% |
| 14A or 14B | PI, PTY, TP, EON | 10% |
| Any Other | Other Applications | 15% |
For the purpose of this RDS encoder we use a cycle of 64 groups over a 5.7sec period. There are many ways of organising the groups depending upon the information to be transmitted. Here I give a basic super group organised in 4 sections of 16 groups:
| Section 1 | Section 2 | Section 3 | Section 4 | ||||
|---|---|---|---|---|---|---|---|
| Frame | Group | Frame | Group | Frame | Group | Frame | Group |
| 0 | 0A(0) | 16 | 0A(0) | 32 | 0A(0) | 48 | 0A(0) |
| 1 | 2A(0) | 17 | 2A(4) | 33 | 2A(8) | 49 | 2A(C) |
| 2 | 10A(0) | 18 | 1A(2) | 34 | 1A(4) | 50 | 1A(6) |
| 3 | 1A(0) | 19 | 15B(0) | 35 | 15B(0) | 51 | 15B(0) |
| 4 | 0A(1) | 20 | 0A(1) | 36 | 0A(1) | 52 | 0A(1) |
| 5 | 2A(1) | 21 | 2A(5) | 37 | 2A(9) | 53 | 2A(D) |
| 6 | 15B(0) | 22 | 15B(1) | 38 | 15B(1) | 54 | 15B(1) |
| 7 | 15B(1) | 23 | 6A | 39 | 6A | 55 | 6A |
| 8 | 0A(2) | 24 | 0A(2) | 40 | 0A(2) | 56 | 0A(2) |
| 9 | 2A(2) | 25 | 2A(6) | 41 | 2A(A) | 57 | 2A(E) |
| 10 | 1A(1) | 26 | 1A(3) | 42 | 1A(5) | 58 | 1A(7) |
| 11 | 15B(2) | 27 | 15B(2) | 43 | 15B(2) | 59 | 15B(2) |
| 12 | 0A(3) | 28 | 0A(3) | 44 | 0A(3) | 60 | 0A(3) |
| 13 | 2A(3) | 29 | 2A(7) | 45 | 2A(B) | 61 | 2A(F) |
| 14 | 10A(1) | 30 | 10A(0) | 46 | 10A(1) | 62 | 6A |
| 15 | 15B(3) | 31 | 15B(3) | 47 | 15B(3) | 63 | 15B(3) |
The composition will vary as the transmission content is changed. Up to 4 data set (super block) can be held for different compositions. In the next section we show how the groups are composed and converted to symbols. Many of the groups have data that is spread over several groups sends (eg: 0A(0), 0A(1) ....)