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OverSampling - HALF_DUPLEX mode with reduced range #91
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Here some pictures from oscilloscope: The signal shown is the device 1 rx pin reading What is seems happening is that the transmitter of device 1 is saturating or blinding its receiver sensitivity because of its antenna vicinity. After this it occurs always 80 milliseconds of total silence and no background noise and an unwanted high bit followed by noise and channel back to stable state. It seems that an ack or a packet it is much more difficult to be received if arrives in the 80 milliseconds timeframe following a transmission of the local device transmitter (blinding its own receiver). What it seems occurring, is that the receiver's chip is highering the gain, getting only 0s, until passing the background noise threshold (the unwanted bit). After this process reception can occur properly. So I am working adding the necessary delay to avoid the repection loss in this timeframe. Initial tests implementing this mechanism seems to prove the hypotesis exposed above:
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Issue finally fixed: This is a picture of an There is a reduction in bandwidth because |
Ciao! It's a while I am trying to fix this issue locally, but seems this is harder than expected. I am trying to enable HALF_DUPLEX mode with a couple of cheap ASK/FSK 315/433 modules. After various tests seems the receiver is saturated by the transmitter, so its sensitivity is lowered, and the sync ACK can not be received correctly at far distances, SRX885 in particular has a CS pin that should be set HIGH to receive data and LOW to set the module in sleep mode. I considered possible to solve the issue making the receiver sleep while transmitting and making it awake to get the acknowledge after transmission. I tried to extend the OverSampling strategy with a setter: set_cs_pin to pass the pin, and modified the codebase to set its state where necessary:
But I have the same negative results also sending more than one ACK.
Is there someone with some experience with those modules or with a good SDR ready to help :) ?
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