Anyone using or involved with Software Defined Radio (SDR) or RF SoC technologies ?
I have posted about Software Defined Radio in the past and have been researching other emerging technologies and CAE / CAD toolsets that support this new 'digital' format of receiving 'analog' signals.
There are over (150+) products on the marketplace [I know since I cataloged many of them years ago ] , but there is a push to get all radios into this domain since the old method of super-heterodyning.
So I would like to know if there is anyone out there that has looked into SDR and is using SDR technology ?
This also includes the latest on RF SoC devices using AMD/Xilinx or Intel/Altera FPGAs, or even GPUs from nVidia.
Please provide your experiences below; thank you !
4 Answers
I just searched for SDR and found this awesome site:
https://www.sdr-radio.com/
Seems like he has some good free software to interface with hardware.
Also found this site with ready to buy modules:
https://www.onesdr.com/2019/09/24/the-best-software-defined-radios-sdrs-for-2019/
I was looking into HD radio receiving chips a few months ago for AM/FM HD signals out there and it was hard to find ones that included AM signals too. In general most of the stand alone HD radios I see being sold on the consumer level are not including the HD AM band as a feature.
Maybe this explains it:
https://www.crutchfield.com/S-frUSQtXJFcc/learn/car-hd-radio-tuner.html
"AM radio uses smaller sections of bandwidth than FM. There is not enough bandwidth for HD Radio to give AM stations the same CD-quality signal as FM stations."
Found this though:
https://www.nxp.com/products/audio-and-radio/analog-digital-radio-and-audio/digital-radio-and-processing-system-on-chip:SAF360X
Although I don't see that is has an onboard AM tuner like it does and FM tuner.
I also like this it's relatively low cost compared to other options listed on that page:
https://www.rtl-sdr.com/about-rtl-sdr/
The quotation of AM using smaller bandwidth than FM , yet cannot give CD quality is true in that AM uses 20 KHz per channel of bandwidth of which up to 10 KHz is only usable for audio since AM modulation covers both sidebands, so that is why it is not CD quality : https://grabcad.com/groups/radio-frequency-rf-wireless/questions/anyone-using-or-involved-with-software-defined-radio-sdr-or-rf-soc-technologies
FM radio uses 100 KHz channels and 200 KHz spacing to prevent spatter, but typically can handle 75 KHz deviation and there for can handle up to 44.1 KHz of CD quality audio.
However, this should NOT be assumed that the SDR radio cannot receive AM bands !! The most significant issue is the antenna, the bit quality of the analog to digital converters, speed of the converters, and how capable the software is for filtering.
The Realtek RTL-SDR and other derivate technologies are only for the hobbyist looking to experiment with low cost $25 and antiquated SDR technologies such as QAD (Quadrature Sampling Detectors) which have been supplanted with Direct Conversion Receivers now.
This is all discussed in the SDR book by Andrew Barrow (ZL3DW) which I wrote a thread about.
Also for the NXP parts, these are just good to 108 MHz since the 'Full dual ensemble processing' is 2 × 1.8 Mbit/s or basically 2 Mega Samples per second for stereo.
It does include many of the decoders though if someone is interested in car or home audio applications, but this is not broad enough to get interesting such as into the gigahertz range for Bluetooth, wifi, and other millimeter applications.
