SU1665539A1 - Redundant video amplifier - Google Patents

Abstract

The invention relates to a television (TV) technique and can be used in the construction of video paths of TV centers and TV complexes. The purpose of the invention is to increase reliability. Redundant video amplifier contains blocks 1, 2 correction, blocks 3, 4, amplification, block 7 output matching loads. The goal is achieved by the introduction of blocks 5, 6 of switching, logical blocks 10, 11, blocks 8, 9 of the control of the level of clock pulses, blocks 12, 13 of comparison. The use of blocks 8, 9 with an adjustable time interval ensures the elimination of spurious switches in case of the disappearance of the invariant signs of the TV signal by a time shorter than the set time interval for decision making. The use of blocks 12, 13, 10, 11 ensures the switching of blocks 3, 4 to reserve ones independently of each other upon detection of a malfunction, and allows restoring the operation without transferring to the place of control a large amount of control information necessary to establish a faulty block. 1 hp f-ly, 4 ill.

Description

1

The invention relates to a television (TV) technique and can be used in the construction of video paths of TV centers and TV complexes.

The purpose of the invention is to increase reliability.

Ne figure 1 shows the electrical circuit diagram of the device; Figures 2 and 3 show, respectively, the structural electrical circuits of the level control unit of the sync pulses and the comparison unit; In Fig. 4, timing diagrams explaining the p-cry control of the level of the synchronous pulse oz.

The device contains (Fig. 1) the first 1-l recess 2 correction bars, the first Зи зтс .рой Л blocks of the gain, the first 5 and the second G blocks of the switching unit 7 of the output matching loads, the first 8 and the second 9 blocks of the ontrol of the sync pulse level ( SI), the first 10 and second 11, logical blocks and the first 12 and second 13 comparison blocks. The first (second) SI level control unit contains (Fig. 2) the fixation circuit 14, the first 15 and the second 16 sources of the reference plant. the first G / and the second 18 threshold elements of the first 19 and second 20 short pulse formers, the coincidence element 21, the pulse generator 22 and the synchronous odometer oscillator 23. The first (second) comparison unit contains (FIG. 3) a differential amplifier 24 transient capacitance - b, the detector 76 threshold element 27 and k: very low 23 reference voltage,

Wi rosil tsl1. works as follows.

TV signals from the outputs of blocks 1 and 2 (Fig. 1) are fed to the inputs of blocks 8 and 9, where in circuit 14 (Fig. 2) T B signals (SI) are tied to zero level (Fig. 4a). SI on threshold elements P and 18 are compared with the first and second thresholds of mm voltages generated by sources 15–16 (Figs. 4b, 3h). Christmas Tree 19 and

20 on the trailing edge of the SR, short impulses are produced (fig.4g, d), which advance onto the element 21, the output of which produces a corresponding impulse (fig.4e) at a normal range of the SR (at the same time, at the inputs of the element 21, the pulses from the SI are present This impulse, arriving at the first input of the synchronous single-vibrator 23 (to the second input of which impulses come from the generator 22), blocks its operation (Fig. 4g) .Otherwise, when the scope of the SR is shortened or disappears at the output of the element

21 impulses are not generated and the logic level V is set through a certain delay circuit at the output of block 8 and 9)

When the SR range in television signals at the outputs of blocks 1 and 2 corresponds to the allowable value at the outputs of blocks 8 and 9 -o, the level is logical O, and at the output of logical block 10 is logical O, which corresponds to the initial (normal) state of block 2, wherein a TV signal from the first block 5 passes to the input of blocks 3 and 4, i.e. from the output of block 1, the output of block 2 is loaded at a resistance equivalent to the input resistance of blocks 3, 4, 12 and 13.

If the SI scale in the video signal does not match the specified allowable value or the absence of TV signals at the outputs of blocks 1 and 2, the logic level 1 is set at the outputs of blocks 8 and 9 of the control unit and the logic level 1 remains at the output of logical block 10 the Measurement of the state of block 5 occurs only if the specified conditions of the amplitude of the clock pulses in the TV signal at the output of block 2 and the mismatch at the output of block 1. At this, the output of block 8 has a logical O and at the output of block 9 is logical 1, which results to establish at the output of logic block 10 a logic level that controls the switching of block 5, the output of flea 2 is connected to the input of blocks 3 and 4 and to the first inputs of blocks 12 and 13, and the output of block 1 and to the resistance of the equivalent in block 5. Next TV signal through blocks 3 and 4 steps Em, respectively, on the first and second inputs of block b, as well as on the second inputs of blocks: s 12 and 13, respectively. In blocks 12 and i3, a comparison of the TV signals arriving at their first and second inputs takes place. In this case, the TV signal span from the output of block 3 (4) decreases by a factor of K, where K is the gain factor of block 3 (4). This is necessary to ensure the identity of the span of the TV signals on both arches of block 12 (13),

The differential signal from the output of the differential amplifier (Fig. 3) through the transition capacitance 25 is fed to the detector 26, which converts the output signal level to a constant voltage level proportional to the swing of the difference signal.

With the presence or absence of TV signals at both inputs of the differential amplifier 24, the difference signal does not exceed the threshold level specified by the source 28, and the output of the threshold element 27 then has a logic level 1, which indicates that the corresponding block 3 or 4 is healthy.

In the event of a failure of any of these blocks 3 or 4, the difference signal at the output of the corresponding differential amplifier 24 increases, and consequently, the signal level at the output of the detector 26 increases, which triggers the threshold element 27, resulting in a logic level O output .

The outputs of blocks 12 and 13 and the signals of the comparison results are fed to logic block 11, the output of which is connected via a transistor switch to the control input of the block b.

In the presence of TV signals at the outputs of blocks 3 and 4, both inputs of logic block 11 have a logic level 1, and at its output a logic level of O. At the same time, block b remains in the normal position and TV output from block 3 arrives at its output, and the output of block 4 is loaded with a resistance equivalent to block 7. In the absence of TV signals, the outputs of both blocks 3 and 4 and the inputs at their inputs will have a logic level O at both inputs of logic unit 11, and there will also be a logic level at its output A. Block 6 remains unchanged. The level change at the output of logic block 11 occurs only in the absence of a TV signal at the output of block 3 and the presence of a TV signal at the output of block 4. This triggers block 6, with the result that the block 7 of matching loads receives a TV signal from the block output 4, and the output of block 3 is connected to an equivalent resistance.

The use of the proposed device in television complexes provides increased operational reliability, as well as automatic cascade switching of cascades of redundant view of an amplifier. In addition, the use of control units for clock pulses with an adjustable time interval, after which, in the event of a TV signal failure at the output of the main channel and a TV signal at the output of the backup channel, the decision to switch to the reserve is made, eliminates spurious switches in the event of a failure invariant signs of a TV signal for a time shorter than the established time interval for making a decision. The use of comparator blocks and a logic block ensures that the amplifier stages are switched to the backup stages independently of each other by detecting a malfunction, and it can be restored without transmitting to the control place a large amount of control information necessary to establish the failed block without prior knowledge of each of the configurations. booster

Claims (2)

Claim 1. A redundant video amplifier comprising first and second correction blocks, whose inputs are the first and second inputs of a redundant video amplifier, the first and second amplification blocks, and the output matching loads, the output of which is a redundant video amplifier, therefore that, in order to increase reliability, the first and second switching blocks are introduced, the first logic block, the first and second inputs of which are connected, respectively, with the outputs of the first and second b the second logic block, the first and second inputs of which are connected respectively to the outputs of the first and second comparison blocks, the outputs of the first and second logic blocks are connected respectively to the control inputs of the first and second switching blocks, the first and second signal inputs of the first block switching connected respectively to the outputs of the first and second blocks of the correction, the first and second signal inputs of the second switching unit are connected respectively to the outputs of the first and second Amplification blocks, the inputs of which are combined with the inputs of the first and second comparison blocks and connected to the output of the first switching block, the first and second signal inputs of which are connected respectively to the inputs of the first and second sync pulse level control blocks, the second inputs of the first and second comparison blocks are connected respectively to the first and second inputs of the second switching unit, the output of which is connected to the input of the output matching loads, while the first and second blocks of the level control sync pulses contain t the first and second threshold elements, the first inputs of which are combined and connected to the output of the latching circuit, whose input is the input of the sync pulse level control unit, whose output is the output of the synchronous one-vibrator, the first and second inputs of which are connected respectively to the output of the pulse generator and the output matches, the first and second inputs of which are connected respectively to the outputs of the first and second shapers of short pulses, the inputs of which are connected respectively to the outputs of the first and the second threshold elements, the second inputs of which are connected respectively to the outputs of the first and second reference voltage sources. 2. A video amplifier according to claim 2, wherein the first and second comparison blocks contain a series-connected differential amplifier, a transient capacitor, a detector and a threshold amplifier. an element whose second input is connected to the output of a reference voltage source, the output of the threshold element being the output of the comparison unit, the first and second inputs of which are respectively the first and second inputs of the differential amplifier. FIG. 2 Output Phage # FIG. four