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US 2009/0022246 A1Published application
Communication Device, Multi-Band Receiver, and Receiver
AssigneeNEC Corporation
InventorYoshiaki Ando
Life of this patent
Estimating the term…
Abstract
In a direct-conversion type orthogonal demodulator used in a multi-band receiver, influence to signal-receiving characteristics of the receiver, caused by DC offset drift produced when a band is switched to another, is reduced. In a multi-band receiver including a plurality of orthogonal demodulators each carrying out orthogonal demodulation for each of a plurality of band inputs, a switch which selects one of outputs transmitted from the orthogonal demodulators in accordance with a band-switching control signal and a high pass filter receiving an output transmitted from the switch, a cut-off frequency of the high pass filter is raised when a band is switched to another, to thereby shorten a convergent time of DC offset drift included in an output signal.
Claims25
A communication device including:
- a plurality of orthogonal demodulators each covering each of a plurality of frequency bands, wherein predetermined measurement is carried out in a transmission gap in which a part of a frame in one of said frequency bands is ceased to be transmitted, for the other among said frequency bands, and data in said transmission gap is transmitted;
- and
- a convergent-time shortening unit for, when said one of said frequency bands is switched to said other among said frequency bands, shortening a convergent time of DC offset drift caused by switching one of said orthogonal demodulators to the other.
A communication device including:
- a plurality of orthogonal demodulators each covering each of a plurality of frequency bands, wherein predetermined measurement is carried out in a transmission gap in which a part of a frame in one of said frequency bands is ceased to be transmitted, for the other among said frequency bands, and data in said transmission gap is transmitted;
- and
- a DC short-circuit unit for, when said one of said frequency bands is switched to said other among said frequency bands, DC short-circuiting an output transmitted from an orthogonal demodulator associated with said one of said frequency bands and an output transmitted from an orthogonal demodulator associated with said other among said frequency bands to each other for a predetermined period of time.
A multi-band receiver comprising:
- a plurality of orthogonal demodulators each carrying out orthogonal demodulation for each of a plurality of band inputs;
- a switch which is electrically connected to outputs of said orthogonal demodulators, and selects one of outputs transmitted from said orthogonal demodulators in accordance with a band-switching control signal;
- a high pass filter receiving an output transmitted from said switch;
- a variable gain-amplifying circuit disposed downstream of said high pass filter;
- and
- a convergent-time shortening unit for, when a band is switched to another, shortening a convergent time of DC offset drift caused by switching one of said orthogonal demodulators to the other.
3 more elements
A multi-band receiver comprising:
- a plurality of orthogonal demodulators each carrying out orthogonal demodulation for each of a plurality of band inputs;
- a switch which is electrically connected to outputs of said orthogonal demodulators, and selects one of outputs transmitted from said orthogonal demodulators in accordance with a band-switching control signal;
- a high pass filter receiving an output transmitted from said switch;
- a variable gain-amplifying circuit disposed downstream of said high pass filter;
- and
- a DC short-circuit circuit for, when a band is switched to another, DC short-circuiting an output transmitted from the previous orthogonal demodulator and an output transmitted from a newly selected orthogonal demodulator to each other for a predetermined period of time.
3 more elements
A receiver comprising:
- a plurality of orthogonal demodulators;
- a switch which is electrically connected to outputs of said orthogonal demodulators, and selects one of outputs transmitted from said orthogonal demodulators in accordance with a band-switching control signal;
- a high pass filter receiving an output transmitted from said switch;
- a variable gain-amplifying circuit disposed downstream of said high pass filter;
- and
- a convergent-time shortening unit for, when a band is switched to another, shortening a convergent time of DC offset drift caused by switching one of said orthogonal demodulators to the other.
3 more elements
A receiver comprising:
- a plurality of orthogonal demodulators;
- a switch which is electrically connected to outputs of said orthogonal demodulators, and selects one of outputs transmitted from said orthogonal demodulators in accordance with a band-switching control signal;
- a high pass filter receiving an output transmitted from said switch;
- a variable gain-amplifying circuit disposed downstream of said high pass filter;
- and
- a DC short-circuit circuit for, when a band is switched to another, DC short-circuiting an output transmitted from the previous orthogonal demodulator and an output transmitted from a newly selected orthogonal demodulator to each other for a predetermined period of time.
3 more elements
A communication device including:
- means for carrying out orthogonal demodulation for each of a plurality of frequency bands, wherein predetermined measurement is carried out in a transmission gap in which a part of a frame in one of said frequency bands is ceased to be transmitted, for the other among said frequency bands, and data in said transmission gap is transmitted;
- and
- means for, when said one of said frequency bands is switched to said other among said frequency bands, shortening a convergent time of DC offset drift caused by switching one of said orthogonal demodulators to the other.
A communication device including:
- means for carrying out orthogonal demodulation for each of a plurality of frequency bands, wherein predetermined measurement is carried out in a transmission gap in which a part of a frame in one of said frequency bands is ceased to be transmitted, for the other among said frequency bands, and data in said transmission gap is transmitted;
- and
- means for, when said one of said frequency bands is switched to said other among said frequency bands, DC short-circuiting an output transmitted from an orthogonal demodulator associated with said one of said frequency bands and an output transmitted from an orthogonal demodulator associated with said other among said frequency bands to each other for a predetermined period of time.
A multi-band receiver comprising:
- a plurality of first means for carrying out orthogonal demodulation for each of a plurality of band inputs;
- switch means for being electrically connected to outputs of said first means, and selecting one of outputs transmitted from said first means in accordance with a band-switching control signal;
- high pass filtering means receiving an output transmitted from said switch means;
- variably gain-amplifying means disposed downstream of said high pass filtering means;
- and
- means for, when a band is switched to another, shortening a convergent time of DC offset drift caused by switching one of said first means to the other.
3 more elements
A multi-band receiver comprising:
- a plurality of first means for carrying out orthogonal demodulation for each of a plurality of band inputs;
- switch means for being electrically connected to outputs of said first means, and selecting one of outputs transmitted from said first means in accordance with a band-switching control signal;
- high pass filtering means for receiving an output transmitted from said switch means;
- variably gain-amplifying means disposed downstream of said high pass filtering means;
- and
- DC short-circuit means for, when a band is switched to another, DC short-circuiting an output transmitted from the previous first means and an output transmitted from a newly selected first means to each other for a predetermined period of time.
3 more elements
A receiver comprising:
- a plurality of first means for carrying out orthogonal demodulation;
- switch means for being electrically connected to outputs of said first means, and selecting one of outputs transmitted from said first means in accordance with a band-switching control signal;
- high pass filtering means for receiving an output transmitted from said switch means;
- variably gain-amplifying means disposed downstream of said high pass filtering means;
- and
- means for, when a band is switched to another, shortening a convergent time of DC offset drift caused by switching one of said first means to the other.
3 more elements
A receiver comprising:
- a plurality of first means for carrying out orthogonal demodulation;
- switch means for being electrically connected to outputs of said first means, and selecting one of outputs transmitted from said first means in accordance with a band-switching control signal;
- high pass filtering means receiving an output transmitted from said switch means;
- variably gain-amplifying means disposed downstream of said high pass filtering means;
- and
- means for, when a band is switched to another, DC short-circuiting an output transmitted from the previous orthogonal demodulator and an output transmitted from a newly selected orthogonal demodulator to each other for a predetermined period of time.
3 more elements
Dependencies are inferred from the claim text.