Double super-heterodyne receiver

Abstract

A double superheterodyne receiver comprising a first mixer responsive to a frequency modulated signal and a first local oscillator signal for providing a first intermediate frequency signal having a frequency f.sub.1 and a positive side frequency deviation of +.DELTA.f.sub.1 and a negative side frequency deviation of -.DELTA.f.sub.2 where .DELTA.f.sub.1 =.DELTA.f.sub.2, a second mixer responsive to the first intermediate frequency signal and a second local oscillator signal having a frequency f.sub.s for providing a second intermediate frequency signal having a frequency of f.sub.2 and harmonics nf.sub.2 and (n+1)f.sub.2 where n is positive integer indicating the harmonic of f.sub.2 in the lower side of f.sub.1 which substantially deviates to f.sub.1 +.DELTA.f.sub.1 or to f.sub.1 -.DELTA.f.sub.2 and n+1 indicates the harmonic of f.sub.2 in the upper side of f.sub.1 which substantially deviates to f.sub.1 -.DELTA.f.sub.2 (when nf.sub.2 substantially deviates to f.sub.1 +.DELTA.f.sub.1) or to f.sub.1 +.DELTA.f.sub.1 (when nf.sub.2 substantially deviates to f.sub.1 -.DELTA.f.sub.2).

Dependencies are inferred from the claim text.