Methods, systems, and apparatuses, and combinations and sub-combinations
thereof, for down-converting and up-converting an electromagnetic (EM)
signal are described herein. Briefly stated, in embodiments the invention
operates by receiving an EM signal and recursively operating on
approximate half cycles (1/2, 11/2, 21/2, etc.) of the carrier signal.
The recursive operations can be performed at a sub-harmonic rate of the
carrier signal. The invention accumulates the results of the recursive
operations and uses the accumulated results to form a down-converted
signal. In an embodiment, the EM signal is down-converted to an
intermediate frequency (IF) signal. In another embodiment, the EM signal
is down-converted to a baseband information signal. In another
embodiment, the EM signal is a frequency modulated (FM) signal, which is
down-converted to a non-FM signal, such as a phase modulated (PM) signal
or an amplitude modulated (AM) signal. Up-conversion is accomplished by
controlling a switch with an oscillating signal, the frequency of the
oscillating signal being selected as a sub-harmonic of the desired output
frequency.