Single sideband (SSB) mixers and methods of extracting a SSB signal, which
are capable of outputting a single frequency using a plurality of mixers
and a local oscillating frequency without having to implement
phase-shifting. In one embodiment, a single sideband (SSB) mixer
comprises a first mixer and a second mixer, wherein the first and second
mixers multiply an input IF (intermediate frequency) signal by a local IF
signal having the same frequency of the input IF signal; a band-pass
filter which passes upper sideband signal output from the first mixer; a
third mixer which multiplies the upper sideband signals output from the
band-pass filter by a LO (local oscillating) signal; a fourth mixer which
multiplies the signals output from the second mixer by the LO signal; and
a subtraction device that subtracts output signals of the third mixer
from output signals of the fourth mixer. Accordingly, a quadrature local
oscillator which displaces a phase of a local oscillating signal by
90.degree. at a high frequency is not required. Also, since the SSB mixer
applies the same local oscillating frequency signal to each mixer, the
rejection characteristics against undesired signals can be achieved to a
level of about 70 dB, experimentally.