FM0 (bi-phase space) decoding!

What is the best way to do this.

1) Catch either edge (falling , rising). 2) Catch every edge.

Your answer?

Tahnks

What is the best way to do what? Your question? See below.

-- "If you want to post a followup via groups.google.com, don't use the broken "Reply" link at the bottom of the article. Click on "show options" at the top of the article, then click on the "Reply" at the bottom of the article headers." - Keith Thompson More details at: Also see

This is pretty much the old floppy single-density data decoding problem.

If we convert the incoming data stream into a stream of transition pulses, there are two interleaved pulse trains: clocks at each bit cell boundary and data at the center of each bit cell. You have to identify the streams in some way. The circuit used with disk recording was called data separator, although its main task is to identify the clock edges.

The customary way in FM disk recording was a special clock/data pattern called an address mark, which was detected by the decoder. This was also used to detect the byte boundaries.

A simple way of detecting the clock was a timer of 3/4 bit cell and which was started by the incoming edge. It will sync to the clock edges after the first missing data pulse, but it assumes that the data stream is error-free.

For more robust clock detection, phase-locked loops (PLL) are used.

HTH

--

Tauno Voipio
tauno voipio (at) iki fi

Please read the OP before posting. In fact that was the follow-up and every one could understand;-)

Addition to Tauno Voipio post:

Yeah you are right and I'm also using PLL in my design but the problem is with RF part , yeah my audio data stream is in form of radio frequency . A hell noise and all the time signal is distorted.

What original post? The threat started with "Re: FM0 (bi-phase space) decoding!".

Peter

decoding!".

Peter

Hmm , tahts why i'm saying to look at OP rather thread with 'Re';-)

You can't say look at such-and-such a message because you can't guarantee that everyone recieves all the messages - and in my case I didn't. As a result your message reads like one side of a telephone conversation - perhaps I can figure out what some of it means but it's real hard work.

Peter

Well i use google's interface for UseNet and its simple to view whole thread at a glance. Not sure how other interfaces present useNet threads anyhow I think we should be concentrating on problem nOw ;-)

Any good pointers for bi-phase decoding design? Regards, ali

As you have already been told, Google's interface is badly broken. It is not a proper newsreader, nor a suitable interface for posting - it's merely an interface for searching the archives. If possible, you should use a proper newsreader and a proper Usenet feed - failing that, you should use Google's interface properly.

"If you want to post a followup via groups.google.com, don't use the broken "Reply" link at the bottom of the article. Click on "show options" at the top of the article, then click on the "Reply" at the bottom of the article headers." - Keith Thompson More details at: Also see

If you want to capture both edges, it might be easier to route the signal to two interrupt pins and configure one for rising edges, and the other for falling edges. Timer captures can also be useful here.

"Ali" schreef in bericht news: snipped-for-privacy@i40g2000cwc.googlegroups.com...

I think you should be concentrating on getting a proper newsreader and quit using that broken Google interface to usenet.

Because it is possible to post correctly from Google, new Google posters may get the benefit of the doubt, but their credit quickly evaporates, and certainly when you start lecturing about the whereabouts of the original post.

And to confirm that, *PLONK* !

--
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)

In article , Ali writes

That is obvious. It is broken and ONLY works with google users. The rest of us (that is the vast majority of Usenet users) do not.

Then you are in a MINORITY. You are also breaking the conditions of use of Usenet.

the problem is your incorrect use of Usenet.

If some one joins a conversation and is very rude people tend not to help them.

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\/\/\/\/\ Chris Hills  Staffs  England     /\/\/\/\/
/\/\/ chris@phaedsys.org      www.phaedsys.org \/\/\
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signal to two interrupt pins and configure one for rising edges, and the other for falling edges. Timer captures can also be useful here.

Thanks David sounds interesting, I have tried to capture both edges on the same interrupt pin and now i'll try to capture both edges with tow pins. What kind of software filter I can design to eliminate the noise factor?

Frank Bemelman wrote:

using that broken Google interface to usenet.

get the benefit of the doubt, but their credit quickly evaporates, and certainly when you start lecturing about the whereabouts of the original post. And to confirm that, *PLONK* !

Hmm interesting , ain't gonna confirm anything let the readers decide ;-)

ali

In article , Ali writes

Top posting too.... Are yo deliberately trying to piss people off?

Do you realise how stupid your last comment was... "freedom from applications" like news readers.... you are using a web browser That is an application and it is less secure than a news reader.

You clearly have little knowledge of what you are doing.

You he is right. You can set up the goolge reader to conform to the rules if not you ain't going to get much help

--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills  Staffs  England     /\/\/\/\/
/\/\/ chris@phaedsys.org      www.phaedsys.org \/\/\
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

What's the gripe with the google reply feature? You aren't supposed to reply to a message in the middle of a thread? The preferred reply method is to only add replies at the end of the thread? (This seems moot if the thread is sorted by date in the reader)

The gripe is lack of context within a single message.

For example: here, I've quoted (and attributed) the bit I'm responding to.

This isn't just pedantry: it's simple netiquette.

Steve

In article , BobG writes

I think the other 8 people in this thread who would have helped you with you technical query have told you.

IT DOES NOT WORK in 99% of readers for Usenet. Google is unique in the way it works only about 0.5% of the Usenet users use google.

Now you appear to have been kill filed by the people you need help from because you refuse to work in harmony with the people who could help you.

Your reader works differently to 99% of all the other news readers on Usenet over the last 20 years. Either fit in with the millions of others or go your own way and get no help. Simple choice really

The basic rules, yes there are rules in the charter and FAQ, are

1 Quote the relevant parts of the message you are replying to. 2 Do not top post 3 Be polite. 4 Do not use HMTL 5 Only post binaries in binary NG/s 6 Follow the particular rules for the NG as laid out in the charter 7 Post in the appro,priate NG 8 Do not cross post.

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\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills  Staffs  England     /\/\/\/\/
/\/\/ chris@phaedsys.org      www.phaedsys.org \/\/\
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CH: I think the other 8 people in this thread who would have helped you with you technical query have told you. =========================================== Now I'm really confused. I see 21 messages in the thread, and I only posted once, so no one has told me anything yet except you.

To me it seems like this newsgroup is full of kids who are here to learn from others and when someone asks a question (which they don't know how to respond to), they start arguing on things which should not be discussed in this newsgroup.

No matter the guy in need of reply was rude or polite, does it serve the purpose of this newsgroup to argue on "how to post to newsgroups?"

P.S: My this message contributes to same thing I am complaining of, but it was necessary and is essentially last one. No need to argue or explain.

He (Chris) has apparently mixed you up with the OP, who was also a google poster. Even those of us with real newsreaders don't always pay attention...

The trouble is not to which messages you reply - you can add a reply anywhere you like in a thread. The trouble is that google's interface is broken, so the "reply" button does not work correctly. Cutting and pasting quotations (as you appear to have done) is perhaps better than nothing, but it's going to get very tedious for you after a while. A better solution, lifted from CBFalconer's sig, is:

"If you want to post a followup via groups.google.com, don't use the broken "Reply" link at the bottom of the article. Click on "show options" at the top of the article, then click on the "Reply" at the bottom of the article headers." - Keith Thompson More details at: Also see