US 6,148,181 AGranted

Radio apparatus adapted to remove image components from local oscillating signals

AssigneeKabushiki Kaisha Toshiba

InventorShoji Otaka

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Abstract

A radio apparatus comprises a local oscillation signal generator which includes a first local oscillation unit for generating a first local oscillation signal having a frequency f.sub.LO1 to be divided into third and fourth local oscillation signals having a phase difference of 90 degrees and a second local oscillation unit for generating a second local oscillation signal having a frequency f.sub.LO2 to be divided into fifth and sixth local oscillation signals having a phase difference of 90 degrees. The local oscillation signal generator includes an arithmetic unit for adding or subtracting the multiplication result of the third and fifth local oscillation signals and the multiplication result of the fourth and sixth local oscillation signals to obtain a local oscillation signal from which an image signal is removed.

Claims16

Dependent claims

A radio apparatus comprising:

a local signal generator comprising,
an oscillation circuit adapted to generate at least a first local oscillation signal having a first frequency and a second local oscillation signal having a second frequency,
a first signal generator adapted to generate from the first local oscillation signal third and fourth local oscillation signals having a phase difference of 90 degrees therebetween, and
a second signal generator adapted to generate from the second local oscillation signal fifth and sixth local oscillation signals having a phase difference of 90 degrees therebetween;
and at least one of
a transmitter unit including a section adapted to multiply the third local oscillation signal by the fifth local oscillation signal to obtain a first multiplication result, to multiply the fourth local oscillation signal by the sixth local oscillation signal to obtain a second multiplication result, and to add or subtract the first multiplication result and the second multiplication result in order to obtain a seventh oscillation signal having a suppressed image component, and
a receiver unit adapted to demodulate using the seventh local oscillation signal.

4 more elements

A radio apparatus comprising:

an oscillation circuit adapted to generate a first local oscillation signal having a first frequency and a second local oscillation signal having a second frequency;
a first signal generator adapted to generate from the first local oscillation signal third and fourth local oscillation signals having a phase difference of 90 degrees therebetween;
a second signal generator adapted to generate from the second local oscillation signal fifth and sixth local oscillation signals having a phase difference of 90 degrees therebetween;
a third signal generator adapted to generate a seventh local oscillation signal by adding or subtracting a first multiplication result of the third and fifth local oscillation signals and a second multiplication result of the fourth and sixth local oscillation signals;
a fourth signal generator adapted to generate using the seventh local oscillation signal eighth and ninth local oscillation signals having a phase difference of 90 degrees and respective suppressed image components;
a transmitter unit adapted to modulate using the eighth and ninth local oscillation signals;
and
a receiver unit adapted to demodulate using the eighth and ninth local oscillation signals.

5 more elements

Dependencies are inferred from the claim text.