Artlav
Full Member level 2
The most straightforward SDR is an ADC with an antenna plugged into it.
But how to make one in practice?
What i want is a receiver for a range of 1Mhz and below, that would produce essentially a recording of all EM waves in this range, kind of like a microphone picks up all the air oscillations to make a sound waveform.
Surprisingly enough, i was unable to google up anything for such a direct approach to an SDR, or anything remotely simple.
That suggests that it's either terribly difficult, or quite useless.
As i understand it, after an antenna there should be a filter for 50Hz and similar loud stuff, then some sort of amplifier to get the signal into detectable range for ADC, and a 2 MSPS or higher (twice the target frequency) ADC.
A byte stream from the ADC would then go into an FPGA/CPLD to be either recorded or processed.
The question is - can it be done, and was it done before?
If yes, are there ready-made schematics, or at least any guidelines on which components to choose and what problems to expect?
But how to make one in practice?
What i want is a receiver for a range of 1Mhz and below, that would produce essentially a recording of all EM waves in this range, kind of like a microphone picks up all the air oscillations to make a sound waveform.
Surprisingly enough, i was unable to google up anything for such a direct approach to an SDR, or anything remotely simple.
That suggests that it's either terribly difficult, or quite useless.
As i understand it, after an antenna there should be a filter for 50Hz and similar loud stuff, then some sort of amplifier to get the signal into detectable range for ADC, and a 2 MSPS or higher (twice the target frequency) ADC.
A byte stream from the ADC would then go into an FPGA/CPLD to be either recorded or processed.
The question is - can it be done, and was it done before?
If yes, are there ready-made schematics, or at least any guidelines on which components to choose and what problems to expect?