This prevents loss of precision that occurs with double-precision floats if
timestamps become very large. Timestamps are already large if they contain a
UNIX time value (requires 60 bits; double has 53 bit resolution).
The new system supports:
- time-tagging of log messages
- message priority levels with a threshold below which they are not printed
- colored output of the message priority for easy identification
- compile-time disabling of all logging per C module
So far, it is integrated in the main and rx modules which generate most
messages. Other modules will be migrated in the future.
- implicit declaration of built-in function 'strncpy'
- control reaches end of non-void function
- assignment to 'void (*)(int, siginfo_t *, void *)' from incompatible pointer type 'void (*)(int)'
- passing argument 2 of 'crc_generate_key' discards ‘const’ qualifier;
a bit ugly but signature of crc_generate_key() is wrong
- variable 'linearized_history' set but not used
- typedef is unused
- superfluous arguments to DEBUG_LOG() and fprintf()
- implicit declaration of function 'memset'
- unused arguments
- Ramp-up length increased to 128 symbols (here is room for
improvement!)
- Try to detect the frequency once during ramp-up. To do so, every
second symbol is inverted (to remove the +/-1 symbol toggling) and the
phase difference between neigboring resulting symbols is checked. When
it is low enough for all symbols, the frequency is estimated and
corrected. When frequency estimation was done, it is not retried for a
number of incoming symbols in order to allow the timing estimator to
converge again.
- This approach was verified in a simulated loopback test with frequency
offset and AWGN.
Thomas Kolb
Simon Ruderich