SU113903A1 - Device for automatic measurement of the characteristics of the oscillation of the oscillations of the pulse fronts - Google Patents

Description

Devices are known for measuring the characteristics of the oscillations of the oscillations of the fronts of received pulses relative to the fronts of pulses transmitted over wired and radio links, for example, with an adjustable shift between the point of origin and the moment of arrival of the front of the pulse. A disadvantage of prior art devices for such purposes is the length of the measurement process and inconvenience in handling.

In the proposed device, this disadvantage is eliminated. The peculiarity of the proposed device is that in order to eliminate the operation of measuring the distribution of the transparency of a film, a fixed halftone wedge is placed between the screen of the cathode ray tube and the photographic film. Another feature of the proposed device is that in order to eliminate errors when measuring in a receiving device, a pulse front counter is used associated with a local generator and excluding fronts from fixation that are an odd number behind each other.

FIG. 1 shows a block diagram of a pulse comparison method; FIG. 2 gives an idea of the processes occurring in the measurement; in fig. 3 shows the oscilloscope screen; in fig. 4- the process of photographing through a halftone wedge; in fig. 5-about film.

When transmitting signals of a certain pulse sequence with a duration of all pulses and a multiple of magnitude, the communication channel acts on the transmitted signal, and at the receiver input, the edges of the pulses can be shifted relative to their nominal position by -i. In order to detect this shift in the receiver, nominal position of the front.

Obtaining a direct comparison of two pulse sequences with a large distance of the transmitter from the receiver is not possible.

No. 113903

To eliminate this difficulty, rather stable autonomous generators are used in the proposed device at the receiving and transmitting ends of the communication channel, which is shown in the block diagram of FIG. one.

At the transmitting end, a stable generator controls the moments of pulses to the communication channel, as shown in FIG. 2 (and - oscillations of the generator, b - control signals of the generator, c - transmitted sequence). At the receiving end of the transmission channel, a stable generator serves to create a sawtooth voltage with a period of 2 tons (see Fig. 2 g), the phase of which can be adjusted by the phase shifter. This sawtooth voltage is applied to the horizontal deflection plates of the beam. However, a negative bias is applied to the tube modulator so that horizontal movement of the beam is not visible. The received distorted and shifted pulses are limited in order to preserve only the front shifts (see Fig. 2 d.), And are differentiated (see Fig. 2 e). From the differentiated pulses, pulses of one polarity are extracted and converted into square pulses with a fixed amplitude and duration (see Fig. 2). These pulses are applied to the plates of the vertical deflection of the beam of the tube and at the same time in the positive polarity to the modulator to compensate for the negative potential present on it.

Thus, the moment of appearance of a pulse is recorded on the tube screen in the form of a vertical stroke, the shift of which relative to the start of the sweep depends on the phase difference (frequency) of oscillations of the oscillators and the shift of the received pulse relative to the transmitted one (see Fig. 2h). If we assume that the phase shift between the generators can be ignored, then the position of each chip on the oscilloscope screen is determined only by the offset of the front of the received pulse relative to the front of the transmitted pulse.

For a photograph for some time, the oscilloscope screen using a photographic set-top box, you can get on the film a simultaneous image of such a number of schtrichs, which number of pulses were received during this time (see Fig. 3).

The amount of illumination H reported by the photo layer of a film depends on each brightness of the film or its intensity. illumination on film E and exposure time i., i .e. for one shtriha I Eta. Since the brightness of all slits is the same, the blackening of the film corresponds to the total time of illumination of each point, i.e., the sum of n exposures, where n is the number of strokes defining the same front shift. Thus, the total effect of the streaks gives illumination of Yaz: nfoE.

Optical density of the developed part of the film is: D f (IgH) or in this case

M f {lgnEto)

Since the product Eto for all points is the same, then, using microdensitometers, the distribution of the optical densities of the developed film can be determined from the average time nto the illumination of each point along the scanning line and from

T ,, is the time of photographing, it is possible to determine the frequency of this phase deviation, i.e. the number of

To eliminate the need to use a densitometer, it is proposed to place a grayscale wedge with gradually changing transparency in front of the film (see Fig. 4). In this case, the optical density of the developed film depends not only on the brightness of the fiber and the number of times

ntf,

its appearance at a given location on the screen, but also from the transparency of the halftone wedge. Strokes that rarely repeat in one place give the film's photo layer a sufficient amount of illumination only against the transparent area of the halftone wedge. On the contrary, frequently repeated crystals cause the film to darken in those places where it is covered by darker areas of the wedge. Consequently, the height of the darkened area on the film at a certain scale characterizes the probability of occurrence with a given shift of the pulse front.

With a large number of pulses, the image on the developed film takes the form conventionally shown in FIG. 5, i.e., a temporary shift can be directly measured along one axis, and a probability P of the appearance of a front with such a shift along the other can be counted.

To make a halftone wedge, a segment of a conventional film can be used, exposed in such a way that the transparency of the developed film gradually (smoothly or irregularly) changes.

Subject invention

Claims (2)

1. A device for automatically measuring the characteristics of the distribution of the oscillation probabilities of the pulse fronts, characterized in that, in order to accelerate the measurement and the simplicity of the design, a fixed halftone wedge is used, placed between the screen of the cathode ray tube and the photographic film. 2. A device according to claim 1, characterized in that, in order to eliminate faults in the receiving device, a pulse front counter is used associated with a local oscillator. t-, About II iilllllll