williamp/osmocom-analog
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

C-Netz: Allow SDR using C-Netz without calibration options

Browse Source 
Crystals on SDRs are accurate enough for C-Netz (< 1ppm).
This commit is contained in:
Andreas Eversberg
2018-08-26 08:47:56 +02:00
parent 279dd25b15
commit eac19ddab1
2 changed files with 4 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
docs/c-netz.html
View File

@@ -227,13 +227,15 @@ We need to calibrate the speed of our transmit signal (and receive signal as wel
<p> <p>
<font color="red">Importaint: We need calibrate the signal processing clock!</font> <font color="red">Importaint: We need calibrate the signal processing clock!</font>
<br><br>
You can skip this parts, if you use SDR, because they have more accurate crystals than sound cards.
</p> </p>
<p> <p>
First of all we need a reference clock. First of all we need a reference clock.
Since most computers have standard crystal clocks, we cannot use our system clock without any help. 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. 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. Be sure to choose a place for your PC with constant temperature.
A room inside a building is sufficient. A room inside a building is sufficient.
</p> </p>

2
src/cnetz/main.c
View File

@@ -446,7 +446,7 @@ int main(int argc, char *argv[])
exit(0); 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 <rx ppm>,<tx ppm>'. See documentation for help!\n\n"); printf("No clock speed given. You need to measure clock using '-M' and later correct clock using '-S <rx ppm>,<tx ppm>'. See documentation for help!\n\n");
mandatory = 1; mandatory = 1;
} }