Phase signal filtering apparatus utilizing estimated phase signal

Claim 2

A phase signal filtering apparatus utilizing an estimated phase signal for extracting a desired component from a receiving signal, characterized in that said apparatus comprises: phase signal estimation means (1) for receiving a first phase signal having a first frequency and generating a first filtered signal phase-locked with the first phase signal as an estimated phase signal; phase locked loop means for receiving a second phase signal having a second frequency which corresponds to a predetermined multiple of the first frequency of the first phase signal, and outputting a second filtered signal phase-locked with the second phase signal as a desired phase signal, said phase locked loop means comprising: phase comparator means (4) for receiving the second phase signal and the desired phase signal and generating a phase difference signal; filtering means (5) for low-pass filtering the phase difference signal from said phase comparator means (4); signal generating means (6) for generating a signal having a predetermined frequency in accordance with the output from said filtering means (5); and phase adder means (7) for adding the signal having the predetermined frequency from said signal generating means (6) and the estimated phase signal from said phase signal estimation means (1) and outputting the desired phase signal; and frequency compensation means selectively connected to the estimated phase signal, the second phase signal, and the desired phase signal so that said phase locked loop means has substantially the same low-pass filtering response characteristic as the first frequency of the first phase signal.

Claim 3

An apparatus according to claim 1, characterized in that said phase signal estimation means (1) comprises a phase locked loop having a low-pass filtering response characteristic.

Claim 4

An apparatus according to claim 1, characterized in that said ratio of the first and second frequencies is a ratio of integers N, and N 2 .

Claim 5

An apparatus according to claim 3, characterized in that frequency compensation means includes frequency divider/multiplier means (2) which is connected to an output section of said phase signal estimation means (1) so as to output the estimated phase signal having a frequency N 2 /N, times the frequency of the first filtered signal.

Claim 6

An apparatus according to claim 3, characterized in that said frequency compensation means includes first frequency divider (3) means which is connected to an output section of said phase signal estimation means (1) so as to output the estimated phase signal having a frequency 1/N i the frequency of the first filtered signal, second frequency divider means (8), connected to an input section of the second phase signal, for frequency dividing the frequency of the second phase signal to 1/N 2 , and multiplier means (9), connected to an output section of said phase adder means (2), for outputting the desired phase signal having a frequency N 2 times the frequency of the second filtered signal.

Claim 7

An apparatus according to claim 3, characterized in that said frequency compensation means includes first frequency divider/multiplier means (10), connected to an input section of the second phase signal, for frequency dividing/multiplying the frequency of the second phase signal by Ni/N 2 , and second frequency divider/multiplier means (2), connected to an output section of the phase adder means, for frequency dividing/multiplying the frequency of the second filtered signal by N 2 /Ni.

Claim 8

An apparatus according to claim 1, characterized in that a ratio of the first and second frequencies is selected to be 10 or more.

Claim 9

A phase signal filtering apparatus for receiving first and second input signals, a ratio of frequencies of which is a ratio of integers N, and N 2 , and filtering the second input signal to obtain an output signal, characterized in that said apparatus comprises: a phase signal estimator (1) for receiving the first input signal and generating a filtered signal phase-locked with the first input signal; a first frequency divider/multiplier (2) for receiving the filtered signal and generating an estimated phase signal having a frequency N 2 /Ni times the frequency of the filtered signal; a phase comparator (4) for receiving the second input signal and the output signal and forming a phase difference signal; a filter (5) for low-pass filtering the phase difference signal; a signal generator (6) for generating a signal having a frequency proportional to the output from said filter; and a phase adder (7) for adding phases of the signal having the proportional frequency and the estimated phase signal so as to output the output signal.

Claim 10

A phase signal filtering apparatus for receiving first and second input signals, a ratio of frequencies of which is a ratio of integers N, and N 2 , and filtering the second input signal to obtain an output signal, characterized in that said apparatus comprises: a phase signal estimator (1) for receiving the first input signal and generating a filtered signal phase-locked with the first input signal; a first frequency divider/multiplier (2) for receiving the filtered signal and generating an estimated phase signal having a frequency N 2 /Ni times the frequency of the filtered signal; a phase comparator (4) for receiving the second input signal and the output signal and forming a phase difference signal; a filter (5) for low-pass filtering the phase difference signal; a signal generator (6) for generating a signal having a frequency proportional to the output from said filter; and a phase adder (7) for adding phases of the signal having the proportional frequency and the estimated phase signal so as to output the output signal.

Claim 11

A phase signal filtering apparatus for receiving first and second input signals, a ratio of frequencies of which is a ratio of integers N, and N 2 , and filtering the second input signal to obtain an output signal, characterized in that said apparatus comprises: a phase signal estimator (1) for receiving the first input signal and generating a filtered signal phase-locked with the first input signal; a first frequency divider {3) for receiving the filtered signal and generating an estimated phase signal having a frequency 1/Ni the frequency of the filtered signal; a second frequency divider (8) for receiving the second input signal and generating a first phase signal having a frequency 1/N 2 the frequency of the second input signal; a phase comparator (4) for receiving the first phase signal and a second phase signal and forming a phase difference signal; a filter (5) for low-pass filtering the phase difference signal; a signal generator (6) generating a signal having a frequency proportional to the output from said filter; a phase adder (7) for adding phases of the signal having the proportional frequency and the estimated phase signal so as to output the second phase signal; and a multiplier (9) for receiving the second phase signal and generating the output signal having a frequency N2 times the frequency of the second phase signal.

Claim 12

A phase signal filtering apparatus for receiving first and second input signals, a ratio of frequencies of which is a ratio of integers N, and N 2 , and filtering the second input signal to obtain an output signal, characterized in that said apparatus comprises: a phase signal estimator (1) for receiving the first input signal and generating a filtered signal phase-locked with the first input signal; a first frequency divider {3) for receiving the filtered signal and generating an estimated phase signal having a frequency 1/Ni the frequency of the filtered signal; a second frequency divider (8) for receiving the second input signal and generating a first phase signal having a frequency 1/N 2 the frequency of the second input signal; a phase comparator (4) for receiving the first phase signal and a second phase signal and forming a phase difference signal; a filter (5) for low-pass filtering the phase difference signal; a signal generator (6) generating a signal having a frequency proportional to the output from said filter; a phase adder (7) for adding phases of the signal having the proportional frequency and the estimated phase signal so as to output the second phase signal; and a multiplier (9) for receiving the second phase signal and generating the output signal having a frequency N2 times the frequency of the second phase signal.

Claim 13

A phase signal filtering apparatus for receiving first and second input signals, a ratio of frequencies of which is a ratio of integers N, and N 2 , and filtering the second input signal to obtain an output signal, characterized in that said apparatus comprises: an phase signal estimator (1) for receiving the first input signal and generating an estimated phase signal phase-locked with the first input signal; a second frequency divider/multiplier (10) for receiving the second input signal and generating a first phase signal having a frequency Ni/N 2 times the frequency of the second input signal; a phase comparator (4) for receiving the first phase signal and a second phase signal and forming a phase difference signal; a filter (5) for low-pass filtering the phase difference signal; a signal generator (6) for generating a signal having a frequency proportional to the output from said filter; a phase adder (7) for adding phases of the signal having the proportional frequency and the estimated phase signal so as to output the second phase signal; and a first frequency divider/multiplier for receiving the second input signal and generating the output signal. having a frequency N 2 /N, times the frequency of the second input signal.

Claim 14

A phase signal filtering apparatus for receiving first and second input signals, a ratio of frequencies of which is a ratio of integers N, and N 2 , and filtering the second input signal to obtain an output signal, characterized in that said apparatus comprises: an phase signal estimator (1) for receiving the first input signal and generating an estimated phase signal phase-locked with the first input signal; a second frequency divider/multiplier (10) for receiving the second input signal and generating a first phase signal having a frequency Ni/N 2 times the frequency of the second input signal; a phase comparator (4) for receiving the first phase signal and a second phase signal and forming a phase difference signal; a filter (5) for low-pass filtering the phase difference signal; a signal generator (6) for generating a signal having a frequency proportional to the output from said filter; a phase adder (7) for adding phases of the signal having the proportional frequency and the estimated phase signal so as to output the second phase signal; and a first frequency divider/multiplier for receiving the second input signal and generating the output signal. having a frequency N 2 /N, times the frequency of the second input signal.

Claim 16

A GPS (Global Positioning System) signal PLL filtering apparatus serving as a pre-filtering apparatus used in a GPS receiver which receives three phase signals ψ C/A (t), op(t), and ψ CAR (t) which are sent from a GPS satellite and are related by: and processes the three phase signals to perform positioning or ranging measurement, characterized in that said apparatus comprises: a phase/complex signal converter (41) for receiving the phase signal ψ C/A (t) and generating a (1a)th complex signal ∈ ψ jψ C/A (t) ; a first phase comparator (42) for receiving the (1a)-th complex signal and a (1 b)th complex signal ∈ -jψ C/A (t) and generating a phase difference signal ψd 1 (t) calculated by equations (2) from a phase component ψ C/A (t) C/A (t) of a product ∈ ψ j{ψ C/A (t)- ψ C/A (t) } of the (1 a)th and (1 b)th complex signals: ψ d1 (t) = tan -1 (sinψd1/cosψd1) a first loop filter (43) for receiving the phase difference signal ψd 1 (t) and generating a first oscillation frequency control signal; a first voltage controlled oscillator (44) for receiving the first oscillation frequency control signal and generating a first phase continuous signal having a frequency proportional to the first oscillation frequency control signal; a first frequency divider (45) for receiving and frequency dividing the first phase continuous signal to generate a first complex signal ∈ j ψ C/A (t) (t); a first conjugate complex operator (46) for receiving the first complex signal ∈ j ψ C/A (t) and generating the (1 b)th complex signal ∈ -j ψ C/A (t) conjugate therewith; a phase/complex signal converter (47) for receiving the phase signal Op(t) and generating a (2a)th complex signal ∈jψp(t); a second phase comparator (48) for receiving the (2a)th complex signal and a (2b)th complex signal ∈ -j ψ ,p(t) and generating a phase difference signal ψ d2 (t) calculated by equations (3) from a phase component ψ p (t) - ψ p(t) of a product ∈ j{ψ p (t)- ψ p-(t)} of the (2a)th and (2b)th complex signals: a second loop filter (49) for receiving the phase difference signal O d2 (t) and generating a second oscillation frequency control signal; a second voltage controlled oscillator (50) for receiving the second oscillation frequency control signal and generating a second phase continuous signal having a frequency proportional to the second oscillation frequency control signal; a first phase adder (51) for receiving the first and second phase continuous signals and generating a first sum signal of the two signals; a second frequency divider (52) for receiving and frequency dividing the first sum signal to generate a second complex signal ∈ j ψ p (t) ; a second conjugate complex operator (53) for receiving the second complex signal ∈ j ψ p (t) and generating the (2b)th complex signal ∈ -j $ p (t) conjugated therewith; a phase/complex signal converter (54) for receiving the phase signal ψ CAR (t) and generating a (3a)th complex signal ∈ iψ CAR (t); a third phase comparator (55) for receiving the (3a)th complex signal and a (3b)th complex signal ∈ -j ψ CAR (t) and generating a phase difference signal ψd 3 (t) calculated by equations (4) from a phase component ψ CAR (t) - ψ CAR (t) of a product ∈j{ψ CAR -(t)- CAR (t)} of the (3a)th and (3b)th complex signals: a third loop filter (56) for receiving the phase difference signal ψ d3 '(t) and generating a third oscillation frequency control signal; a third voltage controlled oscillator (57) for receiving the third oscillation frequency control signal and generating a third phase continuous signal having a frequency proportional to the third oscillation frequency control signal; a second phase adder (58) for receiving the second and third phase continuous signals and generating a second sum signal of the two signals; and a third conjugate complex operator (59) for receiving the second sum signal and generating the (3b)-th complex signal ∈ -j ψ CAR (t) conjugated therewith.

Claim 17

A GPS (Global Positioning System) signal PLL filtering apparatus serving as a pre-filtering apparatus used in a GPS receiver which receives three phase signals ψ C/A (t), op(t), and ψ CAR (t) which are sent from a GPS satellite and are related by: and processes the three phase signals to perform positioning or ranging measurement, characterized in that said apparatus comprises: a phase/complex signal converter (41) for receiving the phase signal ψ C/A (t) and generating a (1a)th complex signal ∈ ψ jψ C/A (t) ; a first phase comparator (42) for receiving the (1a)-th complex signal and a (1 b)th complex signal ∈ -jψ C/A (t) and generating a phase difference signal ψd 1 (t) calculated by equations (2) from a phase component ψ C/A (t) C/A (t) of a product ∈ ψ j{ψ C/A (t)- ψ C/A (t) } of the (1 a)th and (1 b)th complex signals: ψ d1 (t) = tan -1 (sinψd1/cosψd1) a first loop filter (43) for receiving the phase difference signal ψd 1 (t) and generating a first oscillation frequency control signal; a first voltage controlled oscillator (44) for receiving the first oscillation frequency control signal and generating a first phase continuous signal having a frequency proportional to the first oscillation frequency control signal; a first frequency divider (45) for receiving and frequency dividing the first phase continuous signal to generate a first complex signal ∈ j ψ C/A (t) (t); a first conjugate complex operator (46) for receiving the first complex signal ∈ j ψ C/A (t) and generating the (1 b)th complex signal ∈ -j ψ C/A (t) conjugate therewith; a phase/complex signal converter (47) for receiving the phase signal Op(t) and generating a (2a)th complex signal ∈jψp(t); a second phase comparator (48) for receiving the (2a)th complex signal and a (2b)th complex signal ∈ -j ψ ,p(t) and generating a phase difference signal ψ d2 (t) calculated by equations (3) from a phase component ψ p (t) - ψ p(t) of a product ∈ j{ψ p (t)- ψ p-(t)} of the (2a)th and (2b)th complex signals: a second loop filter (49) for receiving the phase difference signal O d2 (t) and generating a second oscillation frequency control signal; a second voltage controlled oscillator (50) for receiving the second oscillation frequency control signal and generating a second phase continuous signal having a frequency proportional to the second oscillation frequency control signal; a first phase adder (51) for receiving the first and second phase continuous signals and generating a first sum signal of the two signals; a second frequency divider (52) for receiving and frequency dividing the first sum signal to generate a second complex signal ∈ j ψ p (t) ; a second conjugate complex operator (53) for receiving the second complex signal ∈ j ψ p (t) and generating the (2b)th complex signal ∈ -j $ p (t) conjugated therewith; a phase/complex signal converter (54) for receiving the phase signal ψ CAR (t) and generating a (3a)th complex signal ∈ iψ CAR (t); a third phase comparator (55) for receiving the (3a)th complex signal and a (3b)th complex signal ∈ -j ψ CAR (t) and generating a phase difference signal ψd 3 (t) calculated by equations (4) from a phase component ψ CAR (t) - ψ CAR (t) of a product ∈j{ψ CAR -(t)- CAR (t)} of the (3a)th and (3b)th complex signals: a third loop filter (56) for receiving the phase difference signal ψ d3 '(t) and generating a third oscillation frequency control signal; a third voltage controlled oscillator (57) for receiving the third oscillation frequency control signal and generating a third phase continuous signal having a frequency proportional to the third oscillation frequency control signal; a second phase adder (58) for receiving the second and third phase continuous signals and generating a second sum signal of the two signals; and a third conjugate complex operator (59) for receiving the second sum signal and generating the (3b)-th complex signal ∈ -j ψ CAR (t) conjugated therewith.