About Kalibrate

Kalibrate is a GSM signal detector and clock frequency offset calculator. Clock accuracy and frequency offset is an important aspect of GSM and cellular networks. Out-of-specification clock accuracy causes a number of network issues such as inconsistent network detection by the handset, handover failure, and poor data and voice call performance.

Original version of kalibrate (for use with USRP1):

• http://ttsou.github.com/kalibrate/kal-v0.4.1.tar.bz2

Universal Hardware Driver (UHD):

• http://uhd.ettus.com

Release Notes

The USRP2/N200/N210 is clocked at 100MHz and does not output fractional sample rates. The hardware sample rate warning can be safely ignored.

For USRP1, the original, non-UHD version of kalibrate is recommended.

Build

$ ./bootstrap
$ ./configure
$ make

Examples

USRP2 with internal reference:

$ ./kal -f 1941.6e6
linux; GNU C++ version 4.4.4 20100630 (Red Hat 4.4.4-10); Boost_104100; UHD_20101116.195923.c5043c6

Current recv sock buff size: 50000000 bytes

Warning:
    The hardware does not support the requested RX sample rate:
    Target sample rate: 0.270833 MSps
    Actual sample rate: 0.271739 MSps

kal: Calculating clock frequency offset.
Using PCS-1900 channel 569 (1941.6MHz)
average         [min, max]      (range, stddev)
+ 22.221kHz     [21574, 22791]  (1217, 352.328674)
overruns: 0
not found: 0

USRP2 with external 10MHz reference - Agilent E4438C (OCXO):

$ ./kal -f 1941.6e6 -x
linux; GNU C++ version 4.4.4 20100630 (Red Hat 4.4.4-10); Boost_104100; UHD_20101116.195923.c5043c6

Current recv sock buff size: 50000000 bytes

Warning:
    The hardware does not support the requested RX sample rate:
    Target sample rate: 0.270833 MSps
    Actual sample rate: 0.271739 MSps

kal: Calculating clock frequency offset.
Using PCS-1900 channel 569 (1941.6MHz)
average         [min, max]      (range, stddev)
+  13Hz         [-32, 86]       (118, 34.811478)
overruns: 0
not found: 0

Authors

Kalibrate was originally written by Joshua Lackey jl@thre.at in 2010. Subsequent UHD device support and other changes were added by Tom Tsou tom@tsou.cc.