Normalizing the level of an incoming signal is a critical step in many wireless communications systems and is necessary before further processing can happen in the receiver. This is particularly necessary in digital modulation schemes which encode information in the signal amplitude (e.g. see LIQUID_MODEM_QAM16 in section-modem-digital ).

http://liquidsdr.org/doc/agc/

This tutorial provides an overview of a very simple fininite impulse response least mean-squares equalizer simulation. This is part of my "DSP in 50 lines of C" series.

http://liquidsdr.org/blog/lms-equalizer/

In harmonic analysis, the spectral periodogram is an estimate of the spectral density of a signal over time. For a signal , the spectral content at time may be estimated over a time duration of seconds as where is a temporal windowing function to smooth transitions between transforms.

http://liquidsdr.org/doc/spgram/

This section describes the equalizer module and the functionality of two digital linear adaptive equalizers implemented in liquid , LMS and RLS. Their interfaces are nearly identical; however their internal functionality is quite different.

http://liquidsdr.org/doc/equalization/

This section describes the finite impulse response filter design capabilities in liquid. This includes basic low-pass filter design using the windowed- method, square-root Nyquist filters, arbitrary design using the Parks-McClellan algorithm, and some useful miscellaneous functions.

http://liquidsdr.org/doc/firdes/

Packaged with liquid are benchmarks to determine the speed each signal processing element can run on your machine.

http://liquidsdr.org/doc/benchmarks/

The symsync object is a multi-rate symbol timing synchronizer useful for locking a received digital signal to the receiver's clock. It is effectively the same as the resamp object, but includes an internal control mechanism for tracking to timing phase and frequency offsets.

http://liquidsdr.org/doc/symsync/