RU2011119371A - METHOD FOR DEMODULATION OF FIBER INTERFEROMETER SIGNAL - Google Patents

Abstract

 1. The method of demodulating the signal of a fiber interferometer, including modulating the phase difference in the interferometer with a harmonic signal, converting the received periodic signal into a sequence of digital samples, calculating the desired phase difference, characterized in that the signal is converted at a frequency three times the frequency of the modulation of the phase difference in the interferometer , form triples of samples from all three samples of each period, after which the calculation of the desired phase difference is carried out for each triple by the formulas:! ! where a = u (0) (C1-C2) + u (1) (C2-C0) + u (2) (C0-C1), b = u (0) (S1-S2) + u (1) ( S2-S0) + u (2) (S0-S1),! where u (0), u (1), u (2) are the values of the samples in the triple, C0 = cos [φ (0)], C1 = cos [φ (1)], C2 = cos [φ (2)] and S0 = sin [φ (0)], S1 = sin [φ (1)], S2 = sin [φ (2)],! where φ (0) = δφmsin [θ0], φ (1) = δφmsin [θ1], φ (2) = δφmsin [θ2],! where δφm is the amplitude of the modulating signal, θ0 is the phase delay of the first reference relative to the beginning of the modulation period, θ1 = θ0 + 2π / 3, θ2 = θ0 + 4π / 3. ! 2. The method according to claim 1, characterized in that the triples of samples are formed from all three samples of the same period with the omission of M-1 periods, where M is an integer> 1. ! 3. A method for demodulating a signal of a fiber interferometer, including modulating the phase difference in the interferometer with a harmonic signal, converting the received periodic signal into a sequence of digital samples, calculating the desired phase difference, characterized in that the signal is converted at a frequency three times the frequency of modulating the phase difference in the interferometer , form triples of samples, combining every three neighboring samples with a shift of one sample, then the calculation of the desired phase difference is carried out for each doy three according to the formulas:! ! where a = u (0) (C1-C2) + u (1) (C2-C0) + u (2) (C0-C1), b = u (0) (S1-S2) + u (1) ( S2-S0) + u (2) (S0-S1

Claims (3)

1. The method of demodulating the signal of a fiber interferometer, including modulating the phase difference in the interferometer with a harmonic signal, converting the received periodic signal into a sequence of digital samples, calculating the desired phase difference, characterized in that the signal is converted at a frequency three times the frequency of the modulation of the phase difference in the interferometer , form triples of samples from all three samples of each period, after which the calculation of the desired phase difference is carried out for each triple by the formulas:

where a = u ⁽⁰⁾ (C ₁ -C ₂ ) + u ⁽¹⁾ (C ₂ -C ₀ ) + u ⁽²⁾ (C ₀ -C ₁ ), b = u ⁽⁰⁾ (S ₁ -S ₂ ) + u ⁽¹⁾ (S ₂ -S ₀ ) + u ⁽²⁾ (S ₀ -S ₁ ), where u ⁽⁰⁾ , u ⁽¹⁾ , u ⁽²⁾ are the values of the samples in the triple, C ₀ = cos [φ ⁽⁰⁾ ], C ₁ = cos [φ ⁽¹⁾ ], C ₂ = cos [φ ^{( 2)} ] and S ₀ = sin [φ ⁽⁰⁾ ], S ₁ = sin [φ ⁽¹⁾ ], S ₂ = sin [φ ⁽²⁾ ], where φ ⁽⁰⁾ = δφ _m sin [θ ₀ ], φ ⁽¹⁾ = δφ _m sin [θ ₁ ], φ ⁽²⁾ = δφ _m sin [θ ₂ ], where δφ _m is the amplitude of the modulating signal, θ ₀ is the phase delay of the first reference relative to the beginning of the modulation period, θ ₁ = θ ₀ + 2π / 3, θ ₂ = θ ₀ + 4π / 3. 2. The method according to claim 1, characterized in that the triples of samples are formed from all three samples of the same period with the omission of M-1 periods, where M is an integer> 1. 3. A method for demodulating a signal of a fiber interferometer, including modulating the phase difference in the interferometer with a harmonic signal, converting the received periodic signal into a sequence of digital samples, calculating the desired phase difference, characterized in that the signal is converted at a frequency three times the frequency of modulating the phase difference in the interferometer , form triples of samples, combining every three neighboring samples with a shift of one sample, then the calculation of the desired phase difference is carried out for each up to the three according to the formulas:

where a = u ⁽⁰⁾ (C ₁ -C ₂ ) + u ⁽¹⁾ (C ₂ -C ₀ ) + u ⁽²⁾ (C ₀ -C ₁ ), b = u ⁽⁰⁾ (S ₁ -S ₂ ) + u ⁽¹⁾ (S ₂ -S ₀ ) + u ⁽²⁾ (S ₀ -S ₁ ), where u ⁽⁰⁾ , u ⁽¹⁾ , u ⁽²⁾ are the values of the samples in the triple, C ₀ = cos [φ ⁽⁰⁾ ], C ₁ = cos [φ ⁽¹⁾ ], C ₂ = cos [φ ^{( 2)} ] and S ₀ = sin [φ ⁽⁰⁾ ], S ₁ = sin [φ ⁽¹⁾ ], S ₂ = sin [φ ⁽²⁾ ], where for the first triple - φ ⁽⁰⁾ = δφ _m sin [θ ₀ ], φ ⁽¹⁾ = δφ _m sin [θ ₁ ], φ ⁽²⁾ = δφ _m sin [θ ₂ ], for the second triple φ ^{(0 )} = δφ _m sin [θ ₁ ], φ ⁽¹⁾ = δφ _m sin [θ ₂ ], φ ⁽²⁾ = δφ _m sin [θ ₀ ], for the third triple φ ⁽⁰⁾ = δφ _m sin [θ ₂ ], φ ⁽¹⁾ = δφ _m sin [θ ₀ ], φ ⁽²⁾ = δφ _m sin [θ ₁ ], where δφ _m is the amplitude of the modulating signal, θ ₀ is the phase delay of the first reference relative to the beginning of the modulation period, θ ₁ = θ ₀ + 2π / 3, θ ₂ = θ ₀ + 4π / 3, after which the phase calculation process is repeated.