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FS#9824 - Fix FM channel spacing for Europe

Attached to Project: Rockbox
Opened by Bertrik Sikken (bertrik) - Sunday, 25 January 2009, 15:14 GMT
Last edited by Bertrik Sikken (bertrik) - Thursday, 24 September 2009, 22:06 GMT
Task Type Bugs
Category FM Tuner
Status Closed
Assigned To No-one
Operating System All players
Severity Low
Priority Normal
Reported Version Version 3.1
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

This patch fixes the channel spacing for the "Europe" regional setting. In Europe, a channel spacing of 100 kHz (0.1 MHz) is used for FM radio stations, as per recommendation BS.412 of the ITU-R (International Telecommunications Union - Radiocommunications sector). The current channel spacing of 50 kHz (0.05 MHz) for Europe causes scanning for stations to take twice as long as needed and allows for accidental tuning to incorrect frequencies at x.x5 MHz. This patch fixes that.

The "Korea" regional setting is removed as it is now identical to the "Europe" regional setting. A few stations in Italy still use the 50 kHz (0.05 MHz) spacing so in order to receive these, a "World" regional setting with 50 kHz (0.05 MHz) channel spacing has been added.
This task depends upon

Closed by  Bertrik Sikken (bertrik)
Thursday, 24 September 2009, 22:06 GMT
Reason for closing:  Accepted
Additional comments about closing:  Committed as svn r22822
Comment by Thomas Martitz (kugel.) - Sunday, 25 January 2009, 15:24 GMT
Wouldn't a Korean use the World setting, rather than the Europe one, which is meant to be used for Korea?
Comment by Jonas Häggqvist (rasher) - Sunday, 25 January 2009, 19:04 GMT
And wouldn't an Italian use the Europe setting, rather than the world one?

I really think having some redundancy as I suggested on the ML is a more friendly solution.
Comment by Bertrik Sikken (bertrik) - Sunday, 25 January 2009, 19:33 GMT
Ok, maybe the current patch is no so friendly towards the Koreans or some Italians (although I think it's already an improvement). One solution would be add specific countries (not regions) to the list, but in that case I can see the list easily grow out of control. Perhaps we could cover it by adding an "Asia" setting. Does anyone know what kind of FM settings other countries in Asia use? I don't really like the solution of explicitly specifying the channel spacing, but maybe that's the only way to go.
Comment by Jonas Häggqvist (rasher) - Sunday, 25 January 2009, 20:31 GMT
I don't see the issue in having these settings (other than a bit of waste):

North America: 87.9 - 107.9 MHz, 200 kHz steps, 75 us de-emphasis
Europe: 87.5 - 108.0 MHz, 100 kHz steps, 50 us de-emphasis
Italy: 87.5 - 108.0 MHz, 50 kHz steps, 50 us de-emphasis
Japan: 76.0 - 90.0 MHz, 100 kHz steps, 50 us de-emphasis
Other: 87.5 - 108.0 MHz, 50 kHz steps, 50 us de-emphasis

Italians would pick "Italy" (since that's a better fit than Europe), Koreans would pick "Other" (since there's nothing else that applies to them).
Comment by Thomas Martitz (kugel.) - Sunday, 25 January 2009, 20:32 GMT
Koreans are supposed to pick europe IIUC.
Comment by Jonas Häggqvist (rasher) - Sunday, 25 January 2009, 20:39 GMT
Ah right. So call it Europe/Korea instead :-)
Comment by Bertrik Sikken (bertrik) - Sunday, 25 January 2009, 20:45 GMT
I just downloaded the list of Korean FM stations from fmlist.org and guess what ... all stations are spaced on a 200 kHz (not 100 kHz) grid, just like North America!
Comment by Jonas Häggqvist (rasher) - Sunday, 25 January 2009, 20:46 GMT
Okay, so add a Korea option instead.
Comment by Thomas Martitz (kugel.) - Sunday, 25 January 2009, 21:19 GMT
There's already a Korea option, this patch removes it ;)
Comment by Jonas Häggqvist (rasher) - Sunday, 25 January 2009, 21:25 GMT
I meant to my suggestion:

North America: 87.9 - 107.9 MHz, 200 kHz steps, 75 us de-emphasis
Europe: 87.5 - 108.0 MHz, 100 kHz steps, 50 us de-emphasis
Korea: 87.5 - 108.0 MHz, 200 kHz steps, 50 us de-emphasis
Italy: 87.5 - 108.0 MHz, 50 kHz steps, 50 us de-emphasis
Japan: 76.0 - 90.0 MHz, 100 kHz steps, 50 us de-emphasis
Other: 87.5 - 108.0 MHz, 50 kHz steps, 50 us de-emphasis
Comment by Thomas Martitz (kugel.) - Sunday, 25 January 2009, 21:26 GMT
These sound good imo.
Comment by Bertrik Sikken (bertrik) - Saturday, 08 August 2009, 14:16 GMT
I think I'm going to close this task since the patch is not going in its current shape anyway. I'm not really motivated to sort out the mess called fm region settings (and as a European I'll just keep using the Korean setting...).
Comment by Jonas Häggqvist (rasher) - Saturday, 08 August 2009, 14:19 GMT
What's the issue with my last suggestion? IIRC it covers everyone, and everyone will get the right setting if they pick the region that's most specific to them.
Comment by Jonas Häggqvist (rasher) - Saturday, 08 August 2009, 15:29 GMT
This patch implements my suggestion. I've tested that it compiles on a range of players, but haven't tested it on target yet.
Comment by Bertrik Sikken (bertrik) - Sunday, 20 September 2009, 20:02 GMT
Resynced against 22731, with intention to commit when rockbox 3.4 freeze ends.

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