US 2003/0151443 A1 · DC offset cancel circuit

Abstract

It is intended to provide a DC offset cancel circuit capable of canceling DC offset regardless TDMA system and non-TDMA system, with simple circuit structure, and applicable to dual-mode-structured receivers. Out of output signals having at least two or more phases (OUT1, OUT2, . . . ), at least any one of the signals (OUT1, . . . ) is inputted to a phase converter unit. A signal outputted from the phase converter unit and any one of other signals not inputted to the phase converter unit (OUT 2, . . . ) are inputted to a comparator unit. A comparison result obtained at the comparator unit is fedback to a signal processing section and DC offset components are cancelled. Through the phase converter unit, phase of a signal is converted so as to make phases of signals to be compared same. Thereby, signal components of different phases are cancelled out each other and DC offset components as DC components can be compared.

Claims16

Dependent claims

A DC offset cancel circuit for canceling DC offset components between signals that constitute output signals having at least two phases different to each other when the output signals are outputted from a signal processing section, the DC offset cancel circuit comprising:

a phase conversion section for converting at least any one of the output signals into at least any one of phase-converted signals phase of which is same as a phase of at least any one of other output signals;
and
a comparator section for comparing one of the other output signals and the phase-converted signal and for feeding-back a comparison result to the signal processing section.

A DC offset cancel circuit for canceling DC offset components between two differential output signals when the differential output signals are outputted from a signal processing section, the DC offset cancel circuit comprising:

a first differential amplifier to which one of the differential output signals is inputted;
a second differential amplifier to which other one of the differential output signals is inputted;
a reference voltage generating section that inputs reference voltage to the first differential amplifier and the second differential amplifier;
and
a comparator that compares a first output signal and a second output signal outputted from the fist differential amplifier and outputted the second differential amplifier, respectively.

2 more elements

Dependencies are inferred from the claim text.

DC offset cancel circuit

Life of this patent

DC offset cancel circuit

Life of this patent

Abstract

Claims16