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Imanjl
Joined: 15 Nov 2004
Posts: 42
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| Manchester coding and Fsk modulation |
 Posted: Mon Mar 07, 2005 2:54 pm |
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I want to use Uart and then transmit ascii character through serial port ,
I try to make a wireless link between two 16f877A ,with two rf module
from laipac company : (RPL916f & RPL916f)
These are rf modules with Fsk modulation (NRZ),
Should I balance the data using Manchester code with Fsk modulation?
if not, Can i reach to better performance using Manchester code with these modules or it just reduce my bitrate ...???
if anyone has an idea plz help me . |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Mon Mar 07, 2005 5:45 pm |
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Hola Imanjl:
| Quote: |
These are rf modules with Fsk modulation (NRZ),
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NOP. These modules RPL916/TPL916 use ASK modulation.
AM Modulation have multiple designators:
ASK:Amplitude Shift Keying
OOK:On-Off Keying
OOSK: On-Off Shift Keying
CPCA:Carrier-Present Carrier-Absent
ALL have the same meaning
FSK: Frequency Shift Keying
is another concept. To get Frequency Shift a carrier must always be
present, loading the receiver all the time providing in this way high noise
inmunity.
The strenght or the amplitude of the carrier can be used to determine the
quality of the incoming signal.
Require more power and are more expen$ive.
Humberto |
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Imanjl
Joined: 15 Nov 2004
Posts: 42
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| Posted: Tue Mar 08, 2005 12:25 am |
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Im a little confused Humberto cause I just read the datasheet, look at :
http://www.laipac.com/Downloads/Easy/TLP-RLP%20916F%20Datasheet.pdf
DATASHEET :
| Quote: |
High frequency FM Transmitter module (FSK) . Frequency Range:916.5 MHz . Modulate Mode:FSK |
note : these are two kinds which laipac says : 1_tlp916(ASK) and 2_tlp916F(FSK) ......so with ur explanations what is the difference between these two ?
and I still dont give the answer of my first question ,,
thx. |
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Tue Mar 08, 2005 8:53 am |
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Now I realize that LAIPAC 916 has two "flavors":
TLP/RLP916 ASK Modulation
TLP/RLP916f FSK Modulation
I didnīt ever work with the f series. I know the big brother, the
TRF series wich has built in Codec and CRC modules, it use a 3 wire
comunication with the PIC.
Preamble/Data/Postamble to be sent is written in an internal TRF register
and it does all the task delivering RF in FSK modulation. A rock.
Be sure that the TLP916f has all this features. Bit-banging FSK modulation
is a mess.
Humberto |
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Imanjl
Joined: 15 Nov 2004
Posts: 42
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| Posted: Tue Mar 08, 2005 11:10 am |
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thanx humberto but I realy afraid when I saw ur RED FONT at the last message,,,,,anyway .
So tlp916f is Fsk and have all that features ,
I try to make a test between Manchester code sending and simple ascii sending and then if I get an answer tell u ,,,,,,,,
thx . |
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