Systems and methods are described for a GPS receiver capable of functioning
in the presence of interference. A method includes detecting an
interfering signal including: tuning a band pass filter over a frequency
range; and at each of a plurality of incremental frequencies: computing a
set of band pass filter coefficients; sending the set of band pass filter
coefficients to a digital filter; repeatedly transforming an
analog-to-digital converter output having a quantization level in excess
of 2 bits into a band pass filter output with the digital filter to obtain
a plurality of samples; computing an average of the plurality of samples;
and comparing the average to a threshold to detect peaks that exceed a
threshold. An apparatus includes: an analog radio frequency circuit; an
analog-to-digital converter coupled to the analog radio frequency circuit,
the analog-to-digital converter providing a quantization level in excess
of 2 bits; a digital filter coupled to the analog-to-digital converter;
and a digital circuit coupled to the digital filter.
