Frequency converter circuit with improved intermediate frequency stability

U.S. Patent Number: 5388125

Abstract: A frequency converter circuit which includes a first frequency conversion unit which mixes a received signal and a first local oscillation signal to produce a first intermediate frequency signal and a second frequency conversion unit which mixes the first intermediate frequency signal and a second local oscillation signal to produce a second intermediate frequency signal. Here, the first frequency deviation included in the first local oscillation signal and the second frequency deviation included in the second local oscillation signal are combined and applied to the reference oscillation unit. The oscillation frequency of the reference oscillation unit is subjected to feedback control so that the combined frequency deviation becomes zero. This feedback is formed so that a first and second local oscillation signals are produced based on reference signals obtained by dividing a reference signal having the oscillation frequency by a first dividing ratio and a second dividing ratio.

Inventors: Toda; Yoshifumi (Kawasaki, JP), Onoda; Masahiro (Kawasaki, JP)

Assignee: Fujitsu Limited (Kawasaki, JP)

Application Number: 07/928,420

Issued: 1995-02-07

Expired: 2007-02-07

Classes: 375/332 ; 375/339; 375/344; 455/182.2; 455/192.2; 455/196.1; 455/260; 455/316; 455/318

Field of search: 455/86-87,182.2,192.2,196.1,197.1,209,260,265,314-316,318-319 375/83,93,97,86 329/306

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