I bought one of these 433MHz superheterodyne boards.
It has a SYN500R IC on it.
The board seems to have the figure 3 schematic without the pcb antenna.
There is always a 7kHz squarewave on the output pin. Is that right? I expected nothing until I sent a signal to it, but maybe this tone is always there and I need to look for variations in the pulsewidths (longer lows and highs) for my signal.
Thanks
These cheapo Tx/Rx sets are always 'noisy' giving garbage on the Rx output until a signal is received. Start by looking at RSSI and the data sheet. One would normally use the RSSI signal and a comparator( or AD converter on a micro) to give a starting point for a 'valid' RF transmission. Then you can start looking for valid data...IME these are only any good for low speed networks- 1-2 KHz.
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I'd say no.
That should be the case when the transmitter is on but without any data input. If the transmitter is kept off, you'll probably see random pulses at the receiver output as a result of noise triggering. But not regular 7kHz pulses.
That would be PWM but this Tx-Rx pair is not designed for that. It's OOK or ASK.
I have some of these. They're very noisy, not very good.
Thanks. I'll design in the RSSI signal and start with just detecting that the signal is present.
What do you suggest? I thought something with an IC and a datasheet would be better than the single opamp ones.
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