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Artifact-less ISM band radio transmitter part

kellogs

Jan 7, 2014
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I have tried a couple of FSK/OOK wide frequency range transmitters (among the lines of 100 - 1000 MHz) at 433.92 MHz. They both produce artifacts; i.e. extraneous signals in front and / or after the desired signal - in either OOK or FSK modes. I am sure there are some parts out there that are able to put a clean radio signal in the air. Any examples of such transmitters ?
 

davenn

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Sep 5, 2009
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I have tried a couple of FSK/OOK wide frequency range transmitters (among the lines of 100 - 1000 MHz) at 433.92 MHz. They both produce artifacts; i.e. extraneous signals in front and / or after the desired signal - in either OOK or FSK modes. I am sure there are some parts out there that are able to put a clean radio signal in the air. Any examples of such transmitters ?


Have you heard of band pass filters ?
 

kellogs

Jan 7, 2014
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Thank you!

The separation I wanted is in time, so I guess a passband filter would not do it. Here are two pictures of the artifacts for one of the transmitters:

s8bbJqK.png


2hbAmYY.png


This is a Si4012 transmitter and I already have an answer from Silicon Labs on these artifacts as not being possible to remove based on just I2C commands for the chip. They did not mention the bandpass filter solution, but only to set the transmitter up and then allow a significant delay before I started transmitting. Which would have worked had it not been for my FSK -> OOK mode switch in the middle of the packet train.
 
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