How to weed out the garbage on the receiver in the wireless transmission frequency 433MHz?

Collected the device for wireless reception of the transmission on the basis of receiver MR-RM-5V and the transmitter FS100A. There is analysis of the preamble, that is, the device reads the data only if they were predshestvovali a certain sequence bitikov. On the wire everything is transmitted perfectly. But the receiver before the transmission catches in the constant mode a bunch of garbage (random sequence of 1 and 0). Question: how do I filter out this garbage, to be able to receive traffic data?
April 4th 20 at 00:44
2 answers
April 4th 20 at 00:46
Make the detector of the preamble. The radio will always be random data, you should look for a specific bit sequence (the preamble), and at the bit level. While the preamble is not detected, byte-by-byte technique is not included.
@Ines_Haag74 , I did expect a certain sequence of bits (in my case, 10101010) and then read 8 data bits. But it reads garbage, as the preamble is not necessarily consistently go my 8 bit - Jovany_Keeling commented on April 4th 20 at 00:49
@Jovany_Keeling, the preamble should not be 10101010, but something more complex, e.g. 10110010. This will provide more accurate positioning at the bit level.
Find her need to constantly, shifting bits. UART it does not fit.
Next, be sure the checksum for the data packet. - Ines_Haag74 commented on April 4th 20 at 00:52
@Ines_Haag74, the preamble was changed. Now longer is waiting on the line, then again catches the preamble, but the data is always different and not right. If I understand correctly, the checksum will reveal the presence of errors, but since I pass only 8 bits, I can see that I've made, and that there are errors. The question is, what's between my bits come, even the garbage, so data in the end error. - Jovany_Keeling commented on April 4th 20 at 00:55
@Ines_Haag74, using GPIO. Not UART - Jovany_Keeling commented on April 4th 20 at 00:58
April 4th 20 at 00:48
The receiver has AGC, which automatically adjusts the levels 0 and 1. To do this, the receiver 16 sends alternating 0 and 1.
The package itself must be encoded, for example Manchester coding, i.e. changing 0 to 1 or Vice versa needs to be every beat of the transfer, otherwise the AGC will lose and there will be mistakes.
Well, sure CRC.

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