From eac19ddab123b63259c696556ac8329b73cbaf40 Mon Sep 17 00:00:00 2001 From: Andreas Eversberg Date: Sun, 26 Aug 2018 08:47:56 +0200 Subject: [PATCH] C-Netz: Allow SDR using C-Netz without calibration options Crystals on SDRs are accurate enough for C-Netz (< 1ppm). --- docs/c-netz.html | 4 +++- src/cnetz/main.c | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/docs/c-netz.html b/docs/c-netz.html index 5f965eb0..4a7bef23 100644 --- a/docs/c-netz.html +++ b/docs/c-netz.html @@ -227,13 +227,15 @@ We need to calibrate the speed of our transmit signal (and receive signal as wel

Importaint: We need calibrate the signal processing clock! +

+You can skip this parts, if you use SDR, because they have more accurate crystals than sound cards.

First of all we need a reference clock. Since most computers have standard crystal clocks, we cannot use our system clock without any help. I decided to use the help of the NTP daemon. -After running my system for several days (5 days), the clock speed was accurate enough for a base station. +After running my system for one up to 5 days, the clock speed was accurate enough for a base station. Be sure to choose a place for your PC with constant temperature. A room inside a building is sufficient.

diff --git a/src/cnetz/main.c b/src/cnetz/main.c index c5dd9161..a4fca5f6 100644 --- a/src/cnetz/main.c +++ b/src/cnetz/main.c @@ -446,7 +446,7 @@ int main(int argc, char *argv[]) exit(0); } - if (!set_clock_speed && !measure_speed) { + if (!set_clock_speed && !measure_speed && !use_sdr) { printf("No clock speed given. You need to measure clock using '-M' and later correct clock using '-S ,'. See documentation for help!\n\n"); mandatory = 1; }