SU1486943A1 - Device for determining polarity of periodic pulse video signals - Google Patents

Description

The invention relates to electrical engineering. The device contains a separating capacitor 1 and a polarity indicator 4, which can be used as a voltage comparator. The introduction of a symmetrical limiter amplifier 2 and an integrator allows to increase the reliability of determining the polarity of periodic video signals with a duty cycle ()> 2. 2 Il.

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The invention relates to electrical engineering.

The purpose of the invention is to increase the reliability of determining the polarity of 5 periodic pulsed video signals with a duty cycle () 5 2.

FIG. 1 shows a block diagram of the device; in fig. 2 - voltage diagrams explaining the operation of the device. ten

A device for determining the polarity of periodic pulsed video signals contains a series-connected coupling capacitor 1, an inverting symmetric amplifier-limiter 2, an integrator 3 and a polarity indicator 4, which can be used as a voltage comparator.

The device works as follows 20 times.

The input periodic pulsed video signal and, representing, for example, a sequence of rectangular pulses of positive polarity, amplitude E and duty cycle () (Fig. 2a), flows through capacitor 1 to the input of limiter 2. When passing through capacitor 1, the signal and ₅ loses the constant component, shifts relative to the zero level and turns into a two bipolar signal and _g (Fig. 26). The magnitude of the displacement (constant component) depends on the shape, amplitude of the E 35 and the duty cycle p of the V signal. In this case, the amount of displacement _e and ^I e / <), and positive and negative amplitude signal portions and respectively

υ ^ _Π0Λ = e - Ε / ς = e (1-1 / s})

and _7gr = ^and o = E / o.

In the inverting limiting amplifier 2 with a limiter threshold E _о , large amplitude E, the signal is converted to and _a (Fig. 2c). The constant component and ₄ (Fig. 2d) of the output signal and _a amplifier-limiter 2

and ₄ = Е ₀ (1-1 / <3) - Ео / Ч = Е „(1-2 / Р)

is allocated by integrator 3; ϋ _{4 is} displayed at the output of the polarity indicator 4.

The sign of the DC component _{4 is} uniquely determined by the polarity of the input video signal and, and does not depend on its amplitude E. With a positive polarity of the signal and, the voltage and 4 are positive, with a negative polarity - negative.

Claims (1)

Claim A device for determining the polarity of periodic pulsed video signals, containing a coupling capacitor, the first output of which is connected to the device input, and an indicator of polarity, characterized in that, in order to increase the reliability of determining the polarity of signals with a ratio of O> 2, a symmetric amplifier and integrator are entered into it symmetric amplifier-limiter is connected to the second output of the coupling capacitor, and the output - to the input of the polarity indicator through the integrator. 1486943