From 66b4c8c64bdd538dfe09fc338dcda0db118a9973 Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Sun, 24 Jul 2016 22:20:16 +0200 Subject: Update README --- README.md | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/README.md b/README.md index 0d24a56..251d5d7 100644 --- a/README.md +++ b/README.md @@ -2,28 +2,31 @@ CIR scripts =========== This is a set of script to do correlation measurement measurements -of a DAB signal. The goal is to one day do a channel impulse -response measurement. +of a DAB signal. These scripts can be used to do channel impulse +response measurements using a RTLSDR receiver. Right now there are three scripts: +* correlate_with_ref.py: Finds the NULL symbol of an IQ file, and runs + correlations against the known phase reference to find the components. + * simulate_channel.py: Reads an I/Q file generated by ODR-DabMod and adds some additional components, somehow equivalent to signal reflexions. Each reflexion has a delay and an amplitude factor. -* correlate_with_ref.py: Finds the NULL symbol of an IQ file, and runs - correlations against the known phase reference to find the components +* cir_measure.py: Runs a small webserver that does the correlation + all the time and updates a webpage (INCOMPLETE! NOT FUNCTIONAL!) Example image: ![Example correlation](./example_corr.png) -The example image shows the correlation (horizontal: time delay, vertical: -time offset of the different pieces) between a simulated channel -and the phase reference. -The peaks at delay indices 0, 14 and 25 are clearly visible. +The image shows the received CIR of a real DAB signal captured with the RTLSDR. + +To read in a recording using a RTL-SDR receiver, use: + + rtl_sdr -f 188928000 -s 2048000 -g 20 -S - | \ + dd of=DAB_9A_10_u8_G20.iq bs=2 count=1966080 -Next steps ----------- -Read in a recording using a RTL-SDR receiver. +replace 1966080 (ten Mode 1 transmission frames) by a larger value if you want. Requirements -- cgit v1.2.3