I've used a similar transmitter from Lapaic, and it was also subject to a TON of noise. The good news is that under normal conditions your transmitter will overcome all the noise and be the dominant signal while transmitting. An easy way to filter the noise is to develop a simple handshaking protocol of some sort, like for example always transmit a particular set of characters before the data. The odds that the exact blips of a few ascii characters would show up in random noise are quite poor, so by only accepting whatever comes after your start code then you can be reasonably assured that you're not receiving garbage. A stop code might be pretty useful too if your transmissions are intermittent. I think the guys at sparkfun.com talk a little about this, so you might have a look at their tutorials section under the "foamware" glider project. Nathan even put together a simple protocol that apparently worked pretty well for them and is sharing it with the world. quick link (protocol only): http://www.sparkfun.com/tutorial/ADXL/glider-3base.htm Hope this helps! ----- Original Message ----- From: "Edson Brusque" To: Sent: Thursday, April 15, 2004 9:40 AM Subject: [EE]: RF Rx and Tx modules > Hello, > > I'm testing some transmiters and receivers modules (315MHz e > 434MHz) from Keymark (www.keymark.com.tw). Transmiters are TXC1-0315 and > TXC1-0434. Receivers are RXD1-0315 and RXD1-0434. > > What I'm founding strange is that the receivers output random noise > when the transmiter is OFF (or ON with data pin low). > > This is ok? Am I doin something wrong? > > It seens the receiving routine would need to ignore all this noise. > I think it would be complex. Any good documents on this subject I should > read before doing dumb questions? > > I've tried to find something on www.piclist.com but it seens to be > offline. > > Obrigado, > > Brusque > -- > -- > --------------------------------------------------------------------- > Edson Brusque C.I.Tronics Lighting Designers Ltda > Research and Development Blumenau - SC - Brazil > http://www.suporte.ind.br/ryan/netiqueta.htm www.citronics.com.br > --------------------------------------------------------------------- > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu