SU1241866A2 - Device for measuring angular velocity - Google Patents

Description

Hche

four

The invention relates to the measurement of the TEJibfioft technique and can be used: 1 / w / angular velocity measurement.

The aim of the invention is to improve the accuracy of measurements and the expansion of the dynamic range.

Fig, I shows the diagrams of the device; in fig. 2 - temporary patterns, which remove the operation of the device.

The device consists of a radiation source, a fiber circuit 2 of an I / O device 3, which is a dividing plate or a directional coupler, a photodetector 4, a phase modulator 5 of an additional phase modulator 6, a sawtooth voltage generator 7, a frequency converter unit 8 and a block 9 lock the photoprinter. In this case, the generator output 7 of the sawtooth voltage is connected to the control input of the additional phase modulator 6 installed at one of the fiber contour 2 inputs, and through block 9 for pyro1 and photodetector - to the control input of the photodetector 4, the output of which through the frequency adjustment block. 8 is connected to the input of the generator 7 pill voltage.

The device works as follows. The light beam from the source is split by input-output device 3 into two waves, which are input from opposite ends into fiber circuit 2. After traversing the loop,). in the opposite directions, the waves pass through the input-output device 3 and interfere with the photo-peak 4 When the device rotates at a speed P gp between the counter-waves, due to the Sledge effect, 4 nK qa-t phase difference Ccr - "" R

where R is the radius of the multi-turn kitydL - the length of the light guide j L - the wavelength: s of the radiation. C is the speed of light. Phase modulators 5 and 6 are installed at one or different inputs of the fiber circuit 2. Phase modulator 5 is excited by a harmonic voltage of a fixed frequency and amplitude Gdr selected so that the amplitude of the current of the photodetector and, and the first harmonic of the frequency u: -iH is m -maximal. At 3toM, it is Hi-ieeT the next view;

where A is mordant M1 of the attenuator1, atf „p пол is full of geo-reciprocal phases between the meeting waves, f is the modulation frequency of the phase modulator 5, t is the time. An additional phase modulator 6 from the sawtooth generator 7 is supplied with a sawtooth voltage of variable frequency F and a fixed amplitude.

Combining the functions of two modulators by one is undesirable, since it will lead to the mutual influence of the generators F and f through the common load. The phase delay (f (t) created by the additional phase modulator 6 is proportional to the applied voltage and, therefore, also has a sawtooth shape (Fig. 2, a and D) with a variable slope K (l) and a fixed amplitude Cf „, related as follows:

K (F) T (f

Max

where T - is the period of sawtooth voltage. From here

(f (t) K (F) t F-cp t

Max

Due to the lag effect, the phase delays introduced by the modulator 6 into the opposite waves, shift Ttii in time one relative to the others by the optical wavelength of the wave (Fig. 2 and IP. (For example, for the circuit in Fig. 1, diagram 2, and corresponds to wave, clockwise, 2.5 - counterclockwise). At the interference of counterpropagating waves on a photoframe 4, at the moments of overlapping the leading edges of the sawtooth phase modulation impulses, an additional non-reciprocal phase difference of the counterpropagating waves is formed (Fig 2.6)

fitf, -K (F) t + K (F) (i.t) -K (r) t -F (:,

which can be controlled, the frequency P. changes. The moment of overlapping of the fronts causes the block of photodetector 9 to be locked, locking it for a while. tj - t, fesTs where oi is a number less than I (fig 2.7). At the moments of overlap, the variable component of the photoreceiver 4 at the first harmonic f of the auxiliary phase modulation modulator 5 (Fig. 2 §.) is proportional to