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PostPosted: Sat May 21, 2011 4:27 am 

Joined: Sat May 21, 2011 3:37 am
Posts: 6
hello!! this is my first time to use English describe thing.so, maybe there is some grammar describe don't proper. please forgive!! my question is following::

I am design FM receiver use the chip which name is si4703, and I use the Stereo Tool 6.1 configure the information then send it.When I decode the RDS information about alternative frequency, there is some thing problem when I configure LF/MF to send which belong to (153khz-279khz\531khz -1602khz). for example(alternative frequency setting):
configure 1: 89.9MHZ 102.3MHZ 102.6MHZ 153khz
configure 2: 89.9MHZ 102.3MHZ 153khz
1 is right, 2 maybe not right. when I decode this information. According to configure, the receive data is:
receive data 1:[(#5) (89.9MHZ)] [(102.3MHZ) (102.6MHZ)] [(LF/MFFLAG) (153khz)]
receive date 2:[(#4) (89.9MHZ)] [(102.3MHZ) (LF/MFFLAG)] [(153khz) (Filler code)] NOTE: [ ] is a block which have 2 bytes.

compare data 1 and data 2, the byte (LF/MFFLAG) is the first byte in 1, it is the second byte in 2. Some times, the block maybe lost, so there maybe some question??can you help me ??I am hoping your reply on line ,,Thank you very much!!


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PostPosted: Sat May 21, 2011 4:33 am 

Joined: Sat May 21, 2011 3:37 am
Posts: 6
and my Bibliography is:
UNITED STATES RBDS STANDARD April 9, 1998 Specification of the radio broadcast data system (RBDS);
BS EN 500667:1992 specification of the radio data system (RDS) the European standard.


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PostPosted: Mon May 23, 2011 3:18 am 

Joined: Sat May 21, 2011 3:37 am
Posts: 6
RDS alternative frequency setting:

configure 1: 89.9MHZ 102.3MHZ 102.6MHZ 153khz
configure 2: 89.9MHZ 102.3MHZ 153khz

compare configure 1 and configure 2, when the VHF number which is at the front of the LF/MF(153khz) is odd(configure 1), then the receive data is right. when the number is even(configure 2), then the receive data is wrong.

why? the different configure? is there anyone else?


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PostPosted: Mon May 23, 2011 5:54 am 

Joined: Sat May 21, 2011 3:37 am
Posts: 6
another question about alternative frequency configure:

configure: 89.9MHZ 102.3MHZ 153khz

the following is practice data:
receive data 1:[(#4) (89.9MHZ)]/// [(102.3MHZ) (LF/MFFLAG)] ///[(153khz) (Filler code)]
NOTE: [ ] is a block which have 2 bytes.

but, according to the RDS standard, we should receive data are following(theory data):
receive data 2:[(#3) (89.9MHZ)]/// [(102.3MHZ) (LF/MFFLAG)] ///[(153khz) (Filler code)]

compare receive data 1 and receive data 2 ,byte(#4) and byte (#3)?? could you give me your RDS standard book? :roll:


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PostPosted: Mon May 23, 2011 11:12 am 
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Joined: Mon Mar 17, 2008 1:40 am
Posts: 11213
Hm, I checked and I think you're right. I just generate all the different codes in a sequence, but that fails half of the time.

Workaround for now: Only fill in LW/MW frequencies at odd positions (not counting the LW/MW frequencies themselves).

I'll either have to rearrange the frequencies (don't know if that's allowed, is there an ordering?), or use an extra filler when needed.

I'll add it to the TODO list of version 6.20.


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PostPosted: Wed May 25, 2011 3:49 am 

Joined: Sat May 21, 2011 3:37 am
Posts: 6
I am exciting for your replay :D . Maybe use an extra filler is more better.

I have changed the receive method, and it can receive the configure data rightly now. I think this receive method also fit for the version 6.20.


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PostPosted: Wed May 25, 2011 4:14 am 

Joined: Sat May 21, 2011 3:37 am
Posts: 6
There is another question which puzzle me.

The LF/MF Flag whose byte number is 250, although it indicate one LF/MF frequency follow, Maybe it should not counting in the counter number. I describe it detailed ahead(in the reply 3).


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PostPosted: Mon Jun 06, 2011 12:22 am 
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Joined: Mon Mar 17, 2008 1:40 am
Posts: 11213
Agassi: You are right that the 250 code should not be counted. --> This is fixed in the next BETA (see News section).

Now about where it should be placed (filler or move to the front): I don't know. And I cannot determine it from the official RDS spec! It depends a lot on whether the order matters (if not, there's no need to move it to the front. On the other hand, if you ONLY have an LF/MF frequency, then you have no other choice than using a filler.).


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