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young
Joined: 24 Jun 2004
Posts: 285
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| how to setup and measured the baud rate? |
 Posted: Mon Jan 24, 2005 9:07 am |
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| I am think you setup baud rate and measure it, but How could I do it? |
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Sherpa Doug
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| Posted: Mon Jan 24, 2005 12:23 pm |
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The most practical way is to use an oscilloscope. If you send a string of the character "U" it is real easy to see a bit length.
If you can't get a scope you could send a long string of maybe 1000 characters and time it with a stopwatch. |
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Guest
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| Posted: Mon Jan 24, 2005 12:31 pm |
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Thank you:
I am trying to use the wireless communication. so far for a near diatance it is working well, but a little bit farther, the data start to having delay and some noise. I am trying to intensify my signal to get stable data, and I hear that the baud rate is one of the issue.
I will try to see if baud rate keep stable using oscilloscope, if there is a little different between two chips (same as two 16f76 chips), is it able to calibrate them to same frequency?
what other ways to make a wireless communication more stable? |
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rwyoung
Joined: 12 Nov 2003
Posts: 563
Location: Lawrence, KS USA
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| Posted: Mon Jan 24, 2005 1:39 pm |
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Google for "Manchester Encoding"
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month! |
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Tue Jan 25, 2005 8:43 am |
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| I searched and take a home work at it and understand how manchester en/decoding working. I think it is just a software way to satblize the TX/RX remote communication/ are there any physical encoder/dedcorder that I can use? |
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rwyoung
Joined: 12 Nov 2003
Posts: 563
Location: Lawrence, KS USA
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| Posted: Tue Jan 25, 2005 11:19 am |
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| young wrote: | | I searched and take a home work at it and understand how manchester en/decoding working. I think it is just a software way to satblize the TX/RX remote communication/ are there any physical encoder/dedcorder that I can use? |
Yes you can buy chips but probably most people implement the scheme in either programmable logic (CPLD or FPGA) or a microcontroller.
The general idea is to keep approximately the same number of 0 to 1 as 1 to 0 transitions so that your transmitter and or receiver never spend too long at a single level. Prevents possible saturation of the analog circuits and helps the receiving hardware extract the clock so that it can keep a lock on the data stream.
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Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month! |
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