Systems and methods are presented for digital antenna diversity combining.
In exemplary embodiments of the present invention, at least two antenna
signal paths can be communicably connected to a receiver. Each antenna
signal path can be provided with an RF tuner communicably connected to a
demodulator, which can estimate the signal to noise ratio (SNR) and time
of arrival of its respective antenna signal. In exemplary embodiments of
the present invention, a time alignment circuit can be communicably
connected to each antenna signal path, and a maximum ratio combiner can
be communicably connected to the time alignment circuit. In operation,
the time alignment circuit can use the time of arrival estimate to align
the multiple signals and the maximum ratio combiner can use the SNR
estimate obtained for each antenna signal to respectively weight each
signal and thereby generate a combined output signal. In exemplary
embodiments of the present invention, a switch diversity combiner can be
further provided, and can quickly detect when an antenna signal is
entering a fade, allowing the maximum ratio combiner to set that signal's
weight to zero. In exemplary embodiments of the present invention, a
digital diversity combiner can be provided in a stand alone integrated
circuit, or can be integrated in a larger integrated circuit, such as,
for example, a satellite radio overlay processor.