DE1056740B - Method for the n-line display of phase angles - Google Patents

Description

GERMAN

The invention relates to a method for the "line" display of phase angles between two pulse sequences or quantities from which these can be derived, by means of cathode ray tubes. This method avoids the difficulties which occur with the known methods when the phase angle to be displayed goes beyond 2π. Often the phase angle is taken from a Lissojou figure, or one pulse sequence is split into two voltage components offset by 90 °, which are both placed on a pair of deflection plates of the cathode ray tube. The second pulse sequence is then used to control the brightness of the light spot circulating on a circular path.

A method is also known in which to display the phase angle between two voltages several lines can be written on the fluorescent screen of a cathode ray tube. For that is an additional time tensioning device is required. The cathode ray tube serves as the phase measuring element itself. In this known method, the electron beam writes the lines completely and only becomes deflected at the appropriate points from its rectilinear movement. At a constant phase angle so the deflection voltages are not DC voltages. The necessary synchronization of the Time voltage device causes great difficulties when a large frequency range without switching should be mastered. Broadband synchronization from the range of audio frequencies up to to frequency ranges of a few MHz without switching is only possible with a great deal of technical effort possible. The multi-cell display is only for the purpose of increasing the accuracy, i. h., the The range from 0 to 360 ° is divided into several lines, but not to extend the measuring range. If the voltages to be compared with regard to their phase position are amplitude-modulated, for example, Thus, in the known method, there is an increase in the spread, which is a reading makes it almost impossible.

These disadvantages also exist in other known methods which, without an M-line To lead the display to expand the measuring process, require additional sweep frequency generators, whose frequencies are equal to the measuring frequencies and must be synchronized with the current.

What these and other known methods have in common is that the measuring range of the phase angle cannot be greater than 2π . Much larger phase angles, which can be a multiple of 2π , can be used for n-line display using the method for w-line display of phase angles between two pulse sequences or values from which these can be derived
of phase angles

Applicant:

LICENTIA Patent-Verwaltungs - G. mb H. _r Hamburg 36, Hohe Bleichen 22

Wolfgang Giertz, Berlin-Wilmersdorf,
has been named as the inventor

determine by means of cathode ray tubes according to the invention in that the two pulse trains are directly connected to a phase measuring element with a sawtooth characteristic, ie a linear dependence of the output variable on the phase angle in the range from 2mn to 2 (»+ 1) π, where m is any whole number, and once indirectly after w-fold reduction to a second phase measuring element with a similar characteristic, the output voltage or the output current of the first phase measuring element to a first deflection system of the cathode ray tube and the output voltage or output current of the second alone or in a known manner at the same time a portion of the first voltage or of the first current is fed to a second deflection system with the perpendicular to the first deflection direction.

The invention will be explained in more detail using an exemplary embodiment and FIGS. 1 to 7. In Fig. 1, the two pulse sequences between which the phase angle is to be determined are denoted _{by Z 1} and f _2. You get directly to a first phase measuring element Ph ₁ and indirectly via a frequency divider each with the reduction factor η to a second phase measuring element Ph ₂ . The two phase meters Ph ₁ and Ph ₂ are pulse-controlled and have a sawtooth-shaped characteristic. When the output voltages of the phase meters are applied to the deflection systems of the cathode ray tube K , the light neck moves across the screen in several lines as the phase angle increases, as shown in FIGS. 2 and 3. The mode of operation of the phase meter is shown in more detail in Fig. 4. It is assumed that the pulse train Z ₁ flips a bistable multivibrator in one direction, while it is tilted back in the other direction by the pulse train / ^. Then there are rectangular current or

909 509/193

Claims (1)

Voltage pulses that are: the wider, the greater the phase angle between the two pulse trains. In Fig. 5 the same conditions are shown for the pulse sequences ^ ₁ "and / ₂ " subdivided in the ratio \: n. A curve of the output voltages U ₁ and U _{2 of} the two phase meters is then established as a function of the phase angle φ , as indicated in FIG. 6. These output voltages of the two phase meters result in a line profile as shown in Fig. 2. If the inclination of the lines is perceived as annoying during observation, it is possible to display lines running horizontally. For this purpose, the total voltage is formed from the output voltage of the phase meter Ph ₂ and the inverse output voltage of the phase meter FA ₁ with an amplitude smaller in the ratio 1 : n . The total voltage U _d is a staircase voltage as sketched in Fig. 7. Is z. If, for example, the staircase voltage formed in this way is fed to the vertical pair of deflection plates and the sawtooth-shaped output voltage of the phase meter Ph _{1 is} fed to the horizontal pair of deflection plates of the cathode ray tube, the result is a course of the light spot on the screen with horizontal lines as shown in Fig. 3. In Figs. 2 to 7, a scaling factor Q'r »= 4 of the two frequency dividers has been assumed. However, it is obvious that with this method the phase angle measuring range is quite generally 2πη and that no ambiguities can occur in the phase angle display within this range. In addition to increasing the reduction factor, another possibility for expanding the measuring range is _{to subdivide both pulse trains Z 1} and / ₂ in their pulse train frequency before they reach the phase meter Ph ₁ and via the frequency divider to the phase meter Pfe ₂ . Another advantage of the method is that the spread even with an amplitude modulus of 5. lated pulse trains by the reduction used so> is greatly reduced so that the reading is practically not impaired. PATENT APPLICATION: Method for the w-line display of phase angles between two pulse sequences or quantities, from which these can be derived, by means of cathode ray tubes, characterized in that the two pulse sequences are directly connected to a phase measuring element with a sawtooth characteristic, ie a linear dependence of the output quantity on the phase angle in the range of 2νηπ to 2 (m ± 1) π, where m denotes any whole number, and once indirectly after n-fold reduction are fed to a second phase measuring element with a similar characteristic, the output voltage or the output current of the first phase measuring element to a first deflection system of the cathode ray tube and the output voltage or the output current of the second alone or in a manner known per se at the same time as a portion of the first voltage or the first current is fed to a second deflection system with the perpendicular to the first deflection direction. Considered publications:
German Patent Nos. 677 798, 848 179;
"Frequency" magazine, 1954, issue 10, pp. 304 to 306; "Funkechnik" magazine, 1951, no. 1, p. 15. 1 sheet of drawings