Jeon:
Gnu Radio, per se, knows nothing of voltage. It just sees digital samples as delivered by the hardware. What those samples mean in terms of voltage amplitude as delivered to the antenna port is completely opaque to Gnu Radio.
The LFRX will easily tolerate an input signal with a voltage swing up to +/- 1V. You would have to see what amplitude, in terms of floating-point, is produced in your flow-graph.
On 2015-07-30 01:37, Jeon wrote:
I am building a communication system which uses light. For the system, I've buiult a custom analog circuit and connected it to LFRX with SMA-BNC-Alligator clip.
A simple dry run gives the following:As you can see, data is transmitted with on off keying.
(Please ignore some ripples and fluctuation, it's due to 60 Hz fluorscent light interference. I'll fix it later.)I wonder that such input range (+- 50 mV) is quite acceptable for GNU Radio to manipulate.
Since it's my first time to physically implement a communication system, I only have mathematical and theoretical knowledge, but have little experience and sense about dBm, rx sensitivity and so.But as I can see the waveform not so bad, I think I can manipulate it by equalizing or something...PS: In addition, that 60 Hz interference, would it be better if I filter out that at the analog circuit with high pass filter? Or is it just ok to use high pass filter block in GNU Radio. I think the former is better to reduce the computational cost of GNU Radio. And it is more proper to filter out before it passes through the ADC...Regards,Jeon.
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