Rtl-sdr » History » Version 4
steve-m, 02/19/2016 10:51 PM
| 1 | 1 | steve-m | [[PageOutline]] |
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| 2 | = rtl-sdr = |
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| 3 | |||
| 4 | DVB-T sticks based on the Realtek RTL2832U can be used as a cheap SDR, since the chip allows transferring the raw I/Q samples to the host, which is officially used for DAB/DAB+/FM demodulation. |
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| 5 | |||
| 6 | == Specifications == |
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| 7 | |||
| 8 | 2 | steve-m | The RTL2832U outputs 8-bit I/Q-samples, and the highest theoretically possible sample-rate is 3.2 MS/s, however, the highest sample-rate without lost samples that has been tested so far is 2.8 MS/s. The frequency range is highly dependent of the used tuner, sticks that use the Elonics E4000 offer the best range (64 - 1700 MHz). |
| 9 | 1 | steve-m | |
| 10 | == Supported Hardware == |
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| 11 | |||
| 12 | So far, the following devices are supported: |
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| 13 | |||
| 14 | * ezcap USB 2.0 DVB-T/DAB/FM stick (Elonics E4000 tuner) |
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| 15 | * Terratec NOXON DAB/DAB+ USB-Stick (Fitipower FC0013 tuner) |
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| 16 | 2 | steve-m | |
| 17 | 4 | steve-m | This is the PCB of the ezcap-stick:[[br]][[br]] |
| 18 | [[Image(ezcap_top.jpg,50%)]] |
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| 19 | |||
| 20 | 2 | steve-m | Other sticks based on the RTL2832U might be added in the future as well. |
| 21 | |||
| 22 | == Software == |
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| 23 | |||
| 24 | rtl-sdr is a commandline tool that can initialize the RTL2832, tune to a given frequency, and record the I/Q-samples to a file. |
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| 25 | |||
| 26 | The code can be checked out with: |
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| 27 | {{{ |
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| 28 | git clone git://git.osmocom.org/rtl-sdr.git |
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| 29 | }}} |
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| 30 | |||
| 31 | It can also be browsed on http://cgit.osmocom.org/cgit/rtl-sdr/ |
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| 32 | |||
| 33 | === Building the software === |
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| 34 | To build it, simply run 'make' in the src/-directory and make sure you have libusb1.0-0-dev installed. |
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| 35 | |||
| 36 | === Usage === |
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| 37 | |||
| 38 | Example: To tune to 392.0 MHz, and set the sample-rate to 1.8 MS/s, use: |
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| 39 | |||
| 40 | {{{ |
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| 41 | ./rtl-sdr /tmp/out.bin -s 1800000 -f 392000000 |
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| 42 | }}} |
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| 43 | |||
| 44 | If the device can't be opened, make sure you have the appropriate rights to access the device (udev-rules, or running it as root). |
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| 45 | |||
| 46 | === Known problems === |
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| 47 | |||
| 48 | * If the samples are written to a harddrive, and not a ramdisk, samples may get dropped. An improved version with proper buffering and asynchronous usage of libusb is in the works. |
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| 49 | |||
| 50 | == Using the data == |
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| 51 | |||
| 52 | 3 | steve-m | To convert the data to a standard cfile, following GNU Radio Block can be used:[[br]] |
| 53 | [[br]][[Image(rtl2832-cfile.png)]][[br]][[br]] |
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| 54 | 2 | steve-m | The GNU Radio Companion flowgraph (rtl2832-cfile.grc) is attached to this page. It is based on the FM demodulation flowgraph posted by Alistair Buxton [http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/44461/focus=44525 on this thread]. |
