Decode HD Radio Signals with SDR!

[Scott Greczkowski]

Now THIS is cool!

http://www.rtl-sdr.com/decoding-and-listening-to-hd-radio-nrsc-5-with-an-rtl-sdr/

 

[KE4EST]

Yes, VERY!

 

[harshness]

Since the data isn't encrypted, I suppose it isn't covered under DMCA.

 

[KC7NOA]

Pretty much any sdr that can Rx and pass the data to a demodulating codec will do it.

HackRf LimeSDR-USB ..... how wife is digital FM?

Im stil trying to figure out if my LimeSDR-USB/computer can decode sat TV on a USB3 bus.

Sent from my SM-G930V using the SatelliteGuys app!

 

[harshness]

Im stil trying to figure out if my LimeSDR-USB/computer can decode sat TV on a USB3 bus.

USB 3.0 transfer rates probably don't enter into the discussion. The bandwidth of a satellite transponder is 24-36MHz so the USB3.0 (assuming it is a fast implementation) and LimeSDR hardware is probably still in the game. From there you need to decode the multiplex and that's where everything breaks down.

De-multiplexing between 5 to 24 TV channels from a 24-36MHz transponder in software with a desktop computer seems like a non-starter. This doesn't seem like something that you can hand off to a display adapter or sound card DSP without substantial supervision.

Of course since you can buy a fully functional FTA satellite TV receiver for under $40, there's not much point to trying to building something around a $300 core.

 

[KC7NOA]

Wonder how a 40$ usb device does it but 300$ core cant ....

Your not trying to watch all of the channels ...

Sent from my SM-G930V using the SatelliteGuys app!

 

[N6BY]

Wonder how a 40$ usb device does it but 300$ core cant ....

Your not trying to watch all of the channels ...

Sent from my SM-G930V using the SatelliteGuys app!

Satellite receivers have a DVB demodulator chip and other specialized hardware, which is orders of magnitude more efficient than doing the same thing in software.

All the SDR does is stream raw I/Q to the computer. The rest is all software, and there is a substantial amount of processing to do. And its coming in at a very high rate .....

 

[harshness]

Modern computers have limited dedicated hardware in their sound and display systems (and to a lesser extent, in their network interfacing hardware) but none of it can do some of fundamental the stuff that every satellite receiver can do.

8PSK (or even 8VSB) demultiplexing isn't something you can easily pull one element out of by comparing against a local oscillator. It is a complex mathematical task that demands a lot of very fast processing. There are also components to the signal such as error correction that ride on top of the whole package. In the end, there's just too much data that is coming far too fast for a general purpose processor to handle. You're juggling chain saws, marshmallows and live grenades.

There's a reason that nobody is doing a GPS in software. How many radios does that take? Instead we plug in a relatively inexpensive GPS module that sends text data out through a serial port.

 

[KC7NOA]

Parallela has 1024 RSOC cores ... 1ghz last i had seen ....

Sent from my SM-G930V using the SatelliteGuys app!

 

[harshness]

Parallela has 1024 RSOC cores ... 1ghz last i had seen ....

This is all well and good, but it is still significantly more expensive than a satellite receiver. Cores and clock frequency mean absolutely nothing when we're talking about something like demodulating or decoding. The metrics mean even less when applied to RISC processors.

The processes are straightforward and hardware that is hardwired to execute to those processes are much more economical.