US 7,843,369 B2Granted

Analog-to-digital converter and communication device and wireless transmitter and receiver using the same

AssigneeHitachi, Ltd.

InventorsTomomi Takahashi, Takashi Oshima, Taizo Yamawaki

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Abstract

In a wireless transmitter and receiver, a background calibration type analog-to-digital converter generally occupies a large area because of the phase compensating capacity of an op-amp included in a reference analog-to-digital conversion unit. Further, the calibration type analog-to-digital converter generally requires a sample and hold circuit to exclude influence of parasitic capacitance of wirings, thereby increasing power consumption. Digital calibration is performed by using, as a signal for calibration, an input signal of a digital-to-analog converter in a transmitter circuit of the wireless transmitter and receiver and inputting an output signal from the digital-to-analog converter to the analog-to-digital converter in the receiver circuit.

Claims20

Dependent claims

An analog-to-digital converter that is used for a receiver circuit of a communication device and performs calibration using a digital signal, the analog-to-digital converter comprising:

an analog-to-digital conversion unit that converts an input analog signal into a digital signal;
a calibration section that is connected to an output side of the analog-to-digital conversion unit;
a digital output generating section that receives an output of the analog-to-digital conversion unit;
and
a transfer switch that is installed at an input side of the analog-to-digital conversion unit,
wherein the transfer switch has a function that inputs either an analog input signal received by the receiver circuit or an analog signal for calibration, which is obtained by performing digital-to-analog conversion on a digital signal for calibration in a digital-to-analog converter in a transmitter circuit of the communication device, to the analog-to-digital conversion unit,
wherein the calibration section is connected to an output of the digital output generating section, an output of the analog-to-digital conversion unit, and an input of the digital-to-analog converter, and
wherein the calibration section has a function of acquiring parameters that calibrate the output signal of the analog-to-digital conversion unit, using the digital signal for calibration and an output digital signal of the analog-to-digital conversion unit obtained by inputting the analog signal for calibration to the analog-to-digital conversion unit.

5 more elements

A communication device comprising:

a receiver circuit that includes an analog-to-digital converter performing calibration using a digital signal;
a baseband signal processing section that is connected to an output of the analog-to-digital converter;
and
a transmitter circuit that includes a digital-to-analog converter connected to an output of the baseband signal processing section,
wherein the analog-to-digital converter includes:
an analog-to-digital conversion unit that converts a received analog signal into a digital signal;
a calibration section that is connected to an output side of the analog-to-digital conversion unit;
a digital output generating section that receives an output of the analog-to-digital conversion unit;
and
a transfer switch that is installed at an input side of the analog-to-digital conversion unit,
wherein the transfer switch has a function of inputting either an analog input signal received by the receiver circuit or an analog signal for calibration, which is obtained by performing digital-to-analog conversion on a digital signal for calibration in the digital-to-analog converter in a transmitter circuit, to the analog-to-digital conversion unit,
wherein the calibration section is connected to an output of the digital output generating section, an output of the analog-to-digital conversion unit, and an input of the digital-to-analog converter, and
wherein the calibration section has a function of acquiring parameters that calibrate the output signal of the analog-to-digital conversion unit, using the digital signal for calibration and an output digital signal of the analog-to-digital conversion unit obtained by inputting the analog signal for calibration to the analog-to-digital conversion unit.

10 more elements

A wireless transceiver comprising:

a first switch that switches transmission and reception;
an RF section for reception that is connected to the first switch and an intermediate frequency signal processing section that is connected to the output of the RF section;
an analog-to-digital converter that is connected to the output of the intermediate frequency signal processing section by a second switch and performs calibration using a digital signal;
a baseband signal processing section that is connected to an output of the analog-to-digital converter;
a digital-to-analog converter that is connected to an output of the baseband signal processing section;
an RF section for transmission that is connected to an output of the digital-to-analog converter and the first switch and a third switch that connects the output of the digital-to-analog converter to an input of the analog-to-digital converter;
and
a switch control section that controls opening and closing of the first to third switches,
wherein the output of the digital-to-analog converter is connected to the input of the analog-to-digital converter,
wherein the intermediate frequency signal processing section includes at least one variable gain amplifier,
wherein the analog-to-digital converter includes an analog-to-digital conversion unit, a digital output generating section that is connected to the output of the analog-to-digital converter, and a calibration section that is connected to the output of the digital output generating section, the output of the analog-to-digital conversion unit, and the input of the digital-to-analog converter,
wherein the analog-to-digital conversion unit corresponds to a high sample rate having low precision, and
wherein parameters for calibrating the output of the analog-to-digital conversion unit to the output of the calibration section are acquired by inputting the output of the digital-to-analog converter to the analog-to-digital converter and inputting the output of the analog-to-digital conversion unit, the input of the digital-to-analog converter, and the output of the digital output generating section to the calibration section,
whereby the output of the digital output generating section is the output of the analog-to-digital converter by inputting the parameters and the output of the analog-to-digital conversion unit to the digital output generating section.

11 more elements

Dependencies are inferred from the claim text.