## 2 The Principle of Construction and Description of the Device  
A possible option for constructing an optoelectronic device for measuring signal samples is based on the principle of controlling the phase of the optical coherent flux. The phase of the flux is changed in accordance with the parameters of the radio signal. This flux is used to form an interferogram. The registration of the interferogram parameters amendment gives the opportunity to measure parameters of radio signal. To control the phase of the optical flux, one of the known optical effects can be used. For example, such electro-optical effect can be realized based on the use an electro-optical modulator (EOM) based on an electro-optical Pokkels cell. Such cell gives the opportunity to change the phase of the light flux according to the law of the received radio frequency oscillation [29; 30; 31; 32]. Currently, in the practical use of EOM, preference is given to devices based on the linear transverse electro-optical effect (EOE), for the implementation of which, as a rule, LiNbO\({}_{3}\) material is used as an electro-optical element [33]. The preferred use of LiNbO\({}_{3}\) is due to its properties: stable operation of the modulator in a wide temperature range, low energy losses in the optical and microwave ranges, proven technologies for manufacturing structures of optical modulators of this type. In addition, depending on the design of the EOM based on LiNbO\({}_{3}\), modulators of this type are high-frequency [33].  
In the proposed device, the light flux generated by the laser passes through the EOM and the optical system, falls on the reflective-transmitting Fourier hologram of the holographic interferometer, partially passes through this Fourier hologram and partially diffracts from it [34]. The light flux passing through the Fourier hologram is reflected from a flat mirror, passes in the opposite direction through the Fourier hologram and interferes with the light flux diffracted from the Fourier hologram. As a result of interference, an interferogram is formed in the form of annular interference fringes, the distribution of the intensity of the optical field in the plane of which depends on the refractive index of the EOM material, which varies in accordance with the parameters of the radio signal. The spatial-spectral distribution of the intensity of the optical field in the interferogram plane is recorded by a line of photodetectors with analog-to-digital converters (ADCs) connected to their outputs, performing quantization of signals from the outputs of photodetectors with a discrete step \(\Delta u\). It should be noted that the value determines the quantization discretion when a radio signal is applied directly to the ADC input.  
The block diagram of a holographic optoelectronic radio signal sampling meter using an EOM is shown in Figure 1. The following designations are used in the scheme: 1--a laser with an optical system that provides focusing of the light flux at the point O inside an electro optical crystal waveguide EOM; 2--an EOM made on the basis of a crystal waveguide made of LiNbO\({}_{3}\) material with an optical focusing system of the outgoing light flux with electrodes applied to its surface 3, 3\({}^{\prime}\); 4--Fourier-a hologram of a reflective-transmitting type; 5--a flat mirror; 6--a line of photodetectors with threshold devices connected to their outputs and a device for generating sample values; \(\alpha\)--the angle between the plane of the Fourier hologram 4 and the flat mirror 5.