US7106249B2 — Phase calibration method and apparatus

Claim 1

Independent Claim 102 words

A phase calibration method of a phased array antenna for inserting a calibration signal into a transmit signal, inputting the resultant signal to a prescribed circuit and calibrating phase of the transmit signal using the calibration signal, which is contained in an output signal from said circuit, comprising the steps of: extracting the calibration signal by subtracting the transmit signal from the output signal of said circuit; estimating the phase characteristic of said circuit based upon a change in phase of the calibration signal; and subjecting the transmit signal to a phase adjustment having a characteristic that is opposite the phase characteristic.

Claim 2

Dependent Claim 102 words

A phase calibration method of a phased array antenna for inserting a calibration signal into a transmit signal, inputting the resultant signal to a prescribed circuit and calibrating phase of the transmit signal using the calibration signal, which is contained in an output signal from said circuit, comprising the steps of: extracting the calibration signal by subtracting the transmit signal from the output signal of said circuit; estimating the phase characteristic of said circuit based upon a change in phase of the calibration signal; and subjecting the transmit signal to a phase adjustment having a characteristic that is opposite the phase characteristic.

Claim 3

Dependent Claim 143 words

A phase calibration method of a phased array antenna for inserting a calibration signal into transmit signals in a plurality of branches in turn, estimating a phase characteristic of a circuit to which a respective one of the transmit signals is input and calibrating phase of each transmit signal, comprising the steps of: outputting a first combined signal obtained by combining output signals from said circuit in all branches, and outputting a second combined signal obtained by combining the transmit signals in all branches; extracting the calibration signal by removing the second combined signal from the first combined signal; estimating phase characteristics of said circuits, to which the transmit signals having the inserted calibration signal are input, based upon a change in phase of the calibration signal; and subjecting the transmit signals to phase adjustment having characteristics that are opposite said phase characteristics.

Claim 4

Dependent Claim 143 words

A phase calibration method of a phased array antenna for inserting a calibration signal into transmit signals in a plurality of branches in turn, estimating a phase characteristic of a circuit to which a respective one of the transmit signals is input and calibrating phase of each transmit signal, comprising the steps of: outputting a first combined signal obtained by combining output signals from said circuit in all branches, and outputting a second combined signal obtained by combining the transmit signals in all branches; extracting the calibration signal by removing the second combined signal from the first combined signal; estimating phase characteristics of said circuits, to which the transmit signals having the inserted calibration signal are input, based upon a change in phase of the calibration signal; and subjecting the transmit signals to phase adjustment having characteristics that are opposite said phase characteristics.

Claim 5

Dependent Claim 52 words

The method according to claim 2 , wherein said circuit is a high-frequency circuit that includes a modulator and a high-frequency amplifier, and extraction of the calibration signal is performed by subtracting the second combined signal, which is an analog signal, from an analog signal obtained by demodulating the first combined signal.

Claim 6

Dependent Claim 62 words

The method according to claim 2 , wherein said circuit is a high-frequency circuit that includes a modulator and a high-frequency amplifier, and extraction of the calibration signal is performed by subtracting the second combined signal, which is a digital signal, from a digital signal obtained by demodulating the first combined signal and then subjecting the resultant signal to an analog-to-digital conversion.

Claim 7

Dependent Claim 59 words

The method according to claim 2 , further comprising the steps of: spreading the calibration signal by a spreading code and inserting the spread calibration signal into a prescribed transmit signal; and extracting the calibration signal by despreading a signal, which has been obtained by removing the second combined signal from the first combined signal, by the spreading code.

Claim 8

Dependent Claim 57 words

The method according to claim 2 , wherein if a plurality of transmit signals per branch are transmitted by using and combining a plurality of carriers, then a calibration signal is inserted into each of the transmit signals in each of the branches in turn and the phase of each transmit signal in each branch is calibrated.

Claim 9

Dependent Claim 88 words

The method according to claim 6 , further comprising the steps of: performing modulation of a carrier-combined signal which is obtained by combing said plurality of carriers in each branch, combining the modulated signals obtained in each of the branches and demodulating the resultant combined signal to thereby produce the first combined signal; and subjecting the plurality of transmit signals in each branch to combining of carriers branch by branch, and combining the carrier-combined signals obtained in each of the branches to thereby produce the second combined signal.

Claim 10

Dependent Claim 106 words

The method according to claim 6 , further comprising the steps of: performing modulation of a carrier-combined signal which is obtained by combing said plurality of carriers in each branch, combining the modulated signals obtained in each of the branches and demodulating the resultant combined signal to thereby produce the first combined signal; and combining said carrier-combined signal in each of the branches to generate a branch-combined signal, shifting the frequency of the calibration signal to carrier frequency of the transmit signals into which the calibration signal is inserted, and subtracting the frequency-shifted calibration signal from the branch-combined signal to thereby produce the second combined signal.

Claim 11

Dependent Claim 129 words

The method according to claim 6 , further comprising the steps of: performing modulation of a carrier-combined signal which is obtained by combing said plurality of carriers in each branch, combining the modulated signals obtained in each of the branches and demodulating the resultant combined signal to thereby produce the first combined signal; selectively combining a transmit signal in each of the branches transmitted by a carrier having the same frequency as the carrier frequency of the transmit signals into which the calibration signal is inserted, thereby producing the second combined signal; and extracting the calibration signal by eliminating, through use of a carrier selecting filter, signal components other than said carrier frequency contained in a signal obtained by subtracting the second combined signal from the first combined signal.

Claim 12

Dependent Claim 52 words

The method according to claim 2 , further comprising the steps of: in an initial calibration, performing phase calibration of each transmit signal upon reducing the transmit signal or enlarging the calibration signal; and then performing said phase calibration upon restoring the transmit signal or calibration signal to its original signal level.

Claim 13

Dependent Claim 64 words

The method according to claim 2 , further comprising the steps of: in an initial calibration, performing the phase calibration in turn one transmit signal at a time anal successively transmitting a transmit signal to undergo phase calibration and a transmit signal that has already undergone phase calibration, whereby phase calibration of all transmit signals is carried out; and then performing said phase calibration.

Claim 14

Dependent Claim 17 words

The method according to claim 2 , wherein the phase calibration is controlled periodically or as necessary.

Claim 15

Dependent Claim 175 words

A phase calibration apparatus of a phased array antenna for inserting a calibration signal into transmit signals in a plurality of branches in turn, estimating a phase characteristic of a circuit to which each transmit signal is input and calibrating phase of each transmit signal, comprising: a calibration signal inserting unit for inserting a calibration signal into transmit signals in a plurality of branches in turn; a first combining circuit for outputting a first combined signal by combining output signals from said circuit in all branches; a second combining circuit for outputting a second combined signal by combining the transmit signals in all branches; a calibration signal extracting unit for extracting the calibration signal by removing the second combined signal from the first combined signal; and a phase adjusting unit for estimating phase characteristics of said circuits, to which the transmit signals having the inserted calibration signal are input, based upon a change in phase of the calibration signal, and subjecting the transmit signals to phase adjustment having characteristics that are opposite said phase characteristics.

Claim 16

Dependent Claim 175 words

A phase calibration apparatus of a phased array antenna for inserting a calibration signal into transmit signals in a plurality of branches in turn, estimating a phase characteristic of a circuit to which each transmit signal is input and calibrating phase of each transmit signal, comprising: a calibration signal inserting unit for inserting a calibration signal into transmit signals in a plurality of branches in turn; a first combining circuit for outputting a first combined signal by combining output signals from said circuit in all branches; a second combining circuit for outputting a second combined signal by combining the transmit signals in all branches; a calibration signal extracting unit for extracting the calibration signal by removing the second combined signal from the first combined signal; and a phase adjusting unit for estimating phase characteristics of said circuits, to which the transmit signals having the inserted calibration signal are input, based upon a change in phase of the calibration signal, and subjecting the transmit signals to phase adjustment having characteristics that are opposite said phase characteristics.

Claim 17

Dependent Claim 68 words

The apparatus according to claim 13 , wherein said circuit is a high-frequency circuit that includes a modulator and a high-frequency amplifier; and said calibration signal extracting unit includes: a subtractor for subtracting the second combined signal, which is an analog signal, from a signal obtained by demodulating the first combined signal; and an A/D converter for converting an output signal from said subtractor to a digital signal.

Claim 18

Dependent Claim 69 words

The apparatus according to claim 13 , wherein said circuit is a high-frequency circuit that includes a modulator and a high-frequency amplifier, and said calibration signal extracting unit includes: an A/D converter for converting a signal, which has been obtained by demodulating the first combined signal, to a digital signal; and a subtractor for subtracting the second combined signal, which is a digital signal, from the digital demodulated signal.

Claim 19

Dependent Claim 64 words

The apparatus according to claim 13 , further comprising: a spreader for spreading the calibration signal by a spreading code; an inserting unit for inserting the spread signal into a prescribed transmit signal; and a despreader for despreading a signal, which has been obtained by removing the second combined signal from the first combined signal, by the spreading code, and extracting the calibration signal.

Claim 20

Dependent Claim 60 words

The apparatus according to claim 13 , wherein if a plurality of transmit signals per branch are transmitted by using and combining a plurality of carriers, then said calibration signal inserting unit inserts a calibration signal into each of the transmit signals in each of the branches in turn and calibrates the phase of each transmit signal in each branch.

Claim 21

Dependent Claim 105 words

The apparatus according to claim 17 , wherein said first combining circuit includes: a combiner for combining modulated signal obtained in each branch by performing modulation of a carrier-combined signal which is obtained by combing said plurality of carriers in each branch; and a demodulator for demodulating the resultant combined signal to thereby produce the first combined signal; and said second combining circuit includes: a carrier combiner for subjecting the plurality of transmit signals in each branch to combining of carriers branch by branch; and a combiner for combining the carrier-combined signals obtained in each of the branches to thereby produce the second combined signal.

Claim 22

Dependent Claim 126 words

The apparatus according to claim 17 , wherein said first combining circuit includes: a combiner for combining modulated signal obtained in each branch by performing modulation of a carrier-combined signal which is obtained by combing said plurality of carriers in each branch; and a demodulator for demodulating the resultant combined signal to thereby produce the first combined signal; and said second combining circuit includes: a combiner for combining said carrier-combined signals in each of the branches to generate a branch-combined signal; a frequency shifter for shifting the frequency of the calibration signal to carrier frequency of the transmit signals into which the calibration signal is inserted; and a subtractor for subtracting the frequency-shifted calibration signal from the branch-combined signal to thereby produce the second combined signal.

Claim 23

Dependent Claim 150 words

The apparatus according to claim 17 , wherein said first combining circuit includes: a combiner for combining modulated signal obtained in each branch by performing modulation of a carrier-combined signal which is obtained by combing said plurality of carriers in each branch; and a demodulator for demodulating the resultant combined signal to thereby output the first combined signal; and said second combining circuit includes: a selector for selecting a transmit signal in each of the branches transmitted by a carrier having the same frequency as the carrier frequency of the transmit signals into which the calibration signal is inserted; and a combiner for combining the selected transmit signals, thereby outputting the second combined signal; and said calibration signal extracting unit includes a carrier selecting filter for eliminating signal components other than said carrier frequency contained in a signal obtained by subtracting the second combined signal from the first combined signal.

Claim 24

Dependent Claim 59 words

The apparatus according to claim 13 , further comprising a controller which, in an initial calibration, is for exercising control so as to perform phase calibration of each transmit signal upon reducing the transmit signal or enlarging the calibration signal, and then perform the phase calibration upon restoring the transmit signal or calibration signal to its original signal level.

Claim 25

Dependent Claim 65 words

The apparatus according to claim 13 , further comprising a controller which, in an initial calibration, is for exercising control so as to perform the phase calibration in turn one transmit signal at a time and successive transmit a transmit signal to undergo phase calibration and a transmit signal that has already undergone phase calibration, whereby phase calibration of all transmit signals is carried out.

Claim 26

Dependent Claim 25 words

The apparatus according to claim 13 , further comprising a controller for exercising control so as to control the phase calibration periodically or as necessary.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2009-09-11	2010-03-13	2010-09-12	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2013-09-11	2014-03-13	2014-09-12	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2017-09-11	2018-03-13	2018-09-12	$7700.00	Window Closed / Lapsed

Phase calibration method and apparatus

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