Using Prop/ADC and FT232 to send IQ signals to PC or even standalone type of SDR?
rwgast_logicdesign
Posts: 1,464
in Propeller 1
Im not sure if this is the best forums to post this on but I know there are some really smart guys out there that know a lot about quadrature signals an AC theory along with good digital knowledge.
I recently built a simple 3.579mhz CW transmitter, I ordered a softrock lite which is basically a tuned hi-q direct conversion tayloe detector that plugs in to a PC sound card. The issue is even my X-FI line in will only do 48Khz. Unless the crystal is replaced with a VFO that means max sample rate it 24khz or about 12khz on each side of center frequency of xtal, so that is all the PC SDR software can see. I know my transmitter works via scope and FFT along with RTL-SDR and custom up conversion using mini circuits mixers.
My idea was to make a full on small 80 meter SDR transceiver. I would like to make it hand held and able to plug in to a PC. So first of all lets say the proper ADC is chosen. Would the propeller be able to do FFT along with driving a display and demodulation along with decoding of the the incoming I/Q? Secondly if one were to write a custom serial driver for an SDR program would an FTDI chip be able to stream enough I/Q data to the PC to see the full 3.5Mhz-4.0Mhz band? If not what about using the Cypress FX-2 hi speed USB chip used in saelae devices? Secondly what kind of ADC should I be looking for to do this? There are a lot of nice Audio Codec chips out there that have 192khz bandwidth and two line in channels, but I am looking to somehow get the whole 500khz out to the PC, not use an audio codec and VFO to scroll around.
I recently built a simple 3.579mhz CW transmitter, I ordered a softrock lite which is basically a tuned hi-q direct conversion tayloe detector that plugs in to a PC sound card. The issue is even my X-FI line in will only do 48Khz. Unless the crystal is replaced with a VFO that means max sample rate it 24khz or about 12khz on each side of center frequency of xtal, so that is all the PC SDR software can see. I know my transmitter works via scope and FFT along with RTL-SDR and custom up conversion using mini circuits mixers.
My idea was to make a full on small 80 meter SDR transceiver. I would like to make it hand held and able to plug in to a PC. So first of all lets say the proper ADC is chosen. Would the propeller be able to do FFT along with driving a display and demodulation along with decoding of the the incoming I/Q? Secondly if one were to write a custom serial driver for an SDR program would an FTDI chip be able to stream enough I/Q data to the PC to see the full 3.5Mhz-4.0Mhz band? If not what about using the Cypress FX-2 hi speed USB chip used in saelae devices? Secondly what kind of ADC should I be looking for to do this? There are a lot of nice Audio Codec chips out there that have 192khz bandwidth and two line in channels, but I am looking to somehow get the whole 500khz out to the PC, not use an audio codec and VFO to scroll around.
Comments
Isn't that like two channels of 4 Mega samples per second times 10 bits or so? 80MBits pers second. I don't see how you can get data into or out of the Prop that fast.
As far as FFT on the prop itself I don,t need to see or work the whole band at one time, nor do I need super fast FFT update it is more of a pan adapter to find the traffic. I may not even implement anything besides FFT and CW decoding on the portable side.
I really want to build an SDR out of some specific things i.e Parallela board and some other RF parts, that can can do at least as much as an Ettus for cheaper. Im trying to start small here.