Hi, if I am not mistaken, rtl_sdr(1) outputs 8 bits I/Q's (direct from the dongle).
You should (at least) use 'sox -t raw -b 8 -c 2' to describe the input format and Sox could probably transform it in signed 16 bits (little or big endians) WAV file (?). But I am not sure the rtl_sdr(1) output is 'signed char', as, in dump1090.c, one can read : > Each I and Q value varies from 0 to 255, which represents > a range from -1 to +1. To get from the > unsigned (0-255) range you therefore subtract 127 > (or 128 or 127.5) from each I and Q, giving you > a range from -127 to +128 (or -128 to +127, or -127.5 to +127.5).. (ll140 in https://github.com/bovine/dump1090-robb/blob/master/dump1090.c ) So, maybe, you'll need a small program to get the 8 bits right before using sox(1) (?). xof ========================================== Le 07/10/14 22:53, Andreas Hornig a écrit : > Hi there, > > I am new to this list and want to say hello and also ask my first question. > > How do I set up the recording modes in RTLSDR software for linux and in > sdr# for windows in the same way? > I record the IQ-stream (baseband in sdr#) as 16 bit with my windows OS > and I asked a friend of mine to use rtlsdr and also record the iq-stream > in 16bit. But his file size is only half that of mine. > I want to do auto cross-correlation and both streams need to be in the > same format to be comparable. > > So I am not sure, if I only record with half of the bit-depth, or only > one channel with full bit-depth, or if something was set up wrongly with > the sample rate. > > That are the CMDs we used > > rtl_sdr -f 107.7e6 -s 2048000 -g 36.4 output.bin > > sox -t raw -b 16 -e signed-integer -r 2048000 -B -c2 output.bin > output_2channel.wav > > So, what shall I change in rtlsdr? In sdr# I can only select the > bit-depth, so I think I have to set rtlsdr in a different way, but how? > > Thank you in advance! :) > > > Andreas > >
