rtlsdrblog wrote: ↑Fri Oct 12, 2018 6:36 am
I assume that in the future all smartphones will be using SDR based radios.
Disagree. Current smart phones can already do CDMA/GSM/LTE with traditional ASICs at a reasonable price, so aside from upgradeability and additional flexibility, there is not a whole lot to gain by using an SDR instead. And as you've correctly mentioned, such a phone would likely to use more power, which would be a *major* no-no.
But that does use more battery and CPU power, and no guarantees that they'll be hackable into general purpose receivers.
Hacking them to general purpose receivers would likely require both FW and HW mods, and doing the latter on phones will likely require some exceptional soldering skill.
kelegaya wrote: ↑Wed Oct 10, 2018 5:00 pm
So sorry, i'm a beginner, but i was thinking " Why don't they extract GSM chip of those cheap smartphone to do their usb transceiver"...
Because they contain ASICs (Application Specific Integrated Circuits) that are designed to send/receive (code/decode) GSM/CDMA/LTE/etc., and the phones cannot be easily modified to be used as general purpose transceivers. I presume that in some cases it could be possible to modify them with some kind HW mod, but those mods are not easy to do.
How can a constructor provides smartphones at 40€ with Tx/Rx capability and other cool stuff integrated like wifi, bluetooth, keyboard, operating system etc...
Because they use a handful of ICs that can be very cheap when you are making millions. In addition, I think the lowest frequency mobile phones is currently 600 MHz, (there were lower frequencies used before, but not any more) so the RF chips used in the phones don't need to go down very much. Also, handsets can be sold under cost and subsidized by carriers, so the price you see may not always reflect the true cost.