CS229650B2 - Connexion for multi-channel transmission chains - Google Patents

Description

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BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a circuit that is intended for multi-channel signal transmission chains, for example, so-called common antenna systems. Sources of signals from different channel headunits, such as different frequency converters and / or power amplifier circuits of a collective antenna system, may be coupled to a particular point of the chain, at which point an operational state control and automatic maintenance is required. the prescribed operating states, or restoring such states by monitoring the output levels of individual signal sources. So far, such circuits have been used for this purpose, in which, for example, in one of the latest types, the control signal is fed to the source preamplifier. To generate a control signal, a signal amplification control circuit is connected between the signal source output and the preamplifier control input. If necessary, the control element switches the circuit to a reserve that is still on standby. Such a device is suitable to be equipped with one or more operating state indicating means. Such a connection, which is, moreover, the subject matter of the present invention, is described in HU-PS 168230. There is a description and an overview of the state of the art of the problem solved, and therefore it is not useful to discuss this. here again. This patent suggests that, in comparison with the prior art, improvements have been made in the field of reducing undesired cross-modulation, such that adjusting the output level of the source 2 229 > this would affect the dynamics of automatic regulation. However, further attempts have shown that this earlier solution does not fully satisfy the stringent requirements for the output signal level.

Since the present invention can be used to automatically control and control the operation of a common antenna system, the invention is described in the context of such use. It will be readily apparent to those skilled in the art that the invention, independent of the particular frequency range and modulation method, may be advantageously employed where it is important to maintain a constant output level of any signal source and to impose stringent requirements thereon, where appropriate. where the signal must not, under any circumstances, change its level, while ensuring continuous operation.

Common antenna systems generally operate on the principle of frequency multiplexing; Depending on the particular arrangement of the local circumstances in the supply programs, they may sometimes be used to simultaneously transmit six to eight different television channels and eight to ten different radio programs. The central unit of the common antenna system performs annually received signal amplified in each channel and / or frequency conversion, and broadband amplifiers are connected to the central unit in the form of a string, which distributes the signal 1 via the transmission networks to the destination. . The most important requirement is that the signals supplied to the amplifiers be the same for all amplifiers and have a prescribed level. If both conditions were not met, the quality and usability of the programs received would deteriorate to a large extent due to cross-modulation. .

The wiring according to the invention has the advantages that will be described below. The output level of the signal source is maintained at a prescribed value, and the exact value of the output level can be continuously adjusted during operation. The connection of the circuit according to the invention to the respective line of the line is indicated. If it is not possible to reach the value prescribed for the output of the signal source (amplifier or frequency converter) and if this level cannot be prescribed? output, the unit output is disconnected from the line. The wiring indicates whether the input signal is within the prescribed limits * or if it is larger or smaller. Under normal circumstances, during operation, the reserve unit output that serves as a spare reserve is blocked and not connected to the line, whereas this reserve line unit is connected when the main unit is disconnected. Z for operation that does not comply with the prescribed conditions (if the input level is not correct), the unit receives the "forced operation" command (for example during repair) on the line. In the same way, the unit can be used as an actuator even in the event of a change of function for the unit in operation, as well as for the hot service unit. Finally, the remote fault indication signal can be used.

229 ISO

The invention is based on the recognition that the two essential requirements required for the undisturbed operation of the device cannot be satisfied with the prior art despite their undeniable advantages, since the switching element connecting the unit to the conduit may not have ideal parameters without exceeding the limits of economy. These requirements are that both the output and the input of the RF switch must be adapted to the system and these impedances should remain the same regardless of the operating conditions (on and off).

The economical production of a high-frequency switch (indicated in position 12), particularly where a higher number of such switches is required, is only possible with such an embodiment in which the input impedance is switched on or off, near the boundaries of the control area, namely when approaching the threshold level for disconnecting the unit from the wiring, leads to a step change in the input impedance of the high frequency switch and thus to the size of the reflected signal between the end amplifier and the switch when the threshold is exceeded. Then, the regulating loop, which in the known solution includes a rectifier filter, a differential amplifier and a timing member, receives a signal whose size is directly proportional to the sum of the direct and reflected signal, the value of which is varied in this way. again connected to the line, although the 5 22 · β output signal has not reached the corresponding level, and will be disconnected after that. This repetitive oscillation process is long running if the deviation from the prescribed level is not so great that the signal is no longer able to cause other unit connections to the line again. To limit this phenomenon, the comparator with the hysteresis (Schrnit flip-flop) cannot solve this problem by itself, as it only reduces the area in which the oscillation occurs. For example, if the signal level is reduced due to a gap in the program, the unit is disconnected from the line and the signal is not restored to the line as a result of the operation of the thus regulated control circuit, since the loop gain may even be lower up to ten to fifteen decibels than the system already connected.

Hence, in the sense of the invention, the high-frequency switch is connected to the conduit by means of a directional coupler, in such a way that the reflected signal that is generated by the dynamic change of the input impedance of the switch is not present at all or little to dampen the regulating loops. This circumferential filling requires significantly lower costs than that of a high-frequency switch that meets the two conditions. In this way, a larger number of channels can be expanded according to our previous solution, including its other main features with sufficient cost efficiency, by maintaining both the uninterrupted operation of the two conditions and the automation and other auxiliary functions at the same time, while retaining the previous structure of the device with only a few minor modifications.

According to the invention, a first directional coupler, a switch and a second coupler are connected between the output of the signal source and the corresponding transmission chain node; between any point of the loop to control the level, suitably, for example, comprising a controllable preamplifier connected to the output by a switch control input and a signal processing unit with a delay member and a logic circuit.

The invention is described in more detail by means of one preferred embodiment with the aid of the accompanying drawings.

Fig. 1 is a block diagram of a control loop equipped with a double loop, Fig. 2 shows points where two redundant units of Fig. 1 meet, alternatively connected to a line. In this embodiment, a ballast element 11 is connected to the antenna output, and a signal source 15 is connected thereto in series. The output signal of said source 15 signals the need to maintain a constant level. In the embodiment that serves as an example, the most important parts of the signal source 15 are, inter alia, a preamplifier 2 and a power amplifier 4 interconnected in series, between which an amplifier or frequency converter is connected depending on the local conditions; furthermore, this part is referred to as the intensifying intermediate stage J. The pre-amplifier 2 is a regulated amplifier whose control input is connected to the level-controlling loop 17a of the loop 17a. signal at this point means at the output 15a the need to ensure a constant signal level. In the operating state of the signal source 15, it is connected to the network 16 via a high frequency switch 13, instead of the signal source serving as a hot reserve. Between the signal source 15a of the signal source 15 and the input of the high-frequency switch 13, a first directional coupler 5 is connected as an adaptation member, whilst a second direction coupler 14 is connected as an adapter member to the first radio coupler 14. early as a tap, it is connected between the loop control input 17 and the signal source output 1a. In an exemplary embodiment, the attenuating element 6, the amplifying stage 2, the rectifying stage 8, and the differentiating stage 2 containing the reference source are connected in a level-regulating loop 17, the output of the differentiating stage 2 forming, directly or indirectly, the control loop output 17a level, which in this case is connected to the control input of preamplifier 2 of signal source 15. t The level control loop 17a is connected to the signal processing stage 10 input. The signal output of the signal processing stage 10 is via the delay stage 11 connected to the first input 12a of the logic network 12. The signal processing stage 10 in the exemplary embodiment has four outputs 10a, 10b. 8 229 85 10c, 10d indicating a state that can be connected to the input of other data processing devices or devices.

The first output 12e of the logic network 12 is connected to the control input 13a of the high-frequency switch 13. In addition, the analogue network 12 includes a further input 12b, an output 12c and a terminal 12d via which bidirectional signal exchange can be performed. Referring to Figure 2, I and II are connected in parallel to each corresponding point of the network 16 via respective second directional couplers 14, and their instantaneous operating state (whether in operating state or hot reserve mode) is determined It is evident that on both redundancy units I and II a direct current source U can be connected at a certain level, but at the same time the source is connected at the same time to the same voltage level 12d and 12b, respectively. additional inputs 12b or 12b 'of the respective unit (i or II) and another terminal 12d' or 12d of the corresponding second unit (II or i).

FIG. 2 shows a state in which the DC source U can be connected simultaneously to the next input 12b K.

the other terminal 12a, by closing the switch K connected therebetween.

The high frequency ballast divider 1 adjusts the signal level coming from the antenna to the value prescribed for the signal input 15. After processing, which corresponds to the conventional known methods (amplification and, if necessary, frequency transformation), a signal is supplied to the signal source 15, which is fed to the input of the high frequency switch 13 via the first directional coupler 6. the high-frequency switch 13 is provided with an appropriate level of the first output 12e of the logic network 12; wherein, at the same level, the high-frequency switch 13 connects the output signal of the signal source 15 via the second directional coupler to 16, while in the presence of the second level (due to operating faults) the high-frequency switch 13 is not released, i.e. the unit is disconnected from the loop 17 the control level receives the control signal from the second tap of the first directional coupler, which at the same level as the instantaneous adjustment of the variable attenuator 6, becomes amplified and rectified to the input of the differential stage 2. · The error signal comes from loop output 17a of the loop 17 the input of preamplifier 2 and if the deviation does not exceed the value of the controllable loop 12, the output signal of the prescribed level is reliably transmitted to the output 15a of the signal source 15. The operating setting is performed by adjusting the attenuator 6 to a value at which the system is set to the setpoint. At the same time, the respective error signal also reaches the signal input stage 10 for signal processing. Thus, during operation, it can be determined whether the error signal is inside or outside the control area. In the positive case, the level supplied by the delay member 11 to the input 12a of the network 12 maintains the closed state of the switch 13a thus securing the connection of the unit to the network 16 to the output 12e, while in the negative case the output 12e receives the inverted 10,229 level. therefore, it is sufficient for the signal processing unit 10 only to determine whether the instantaneous level of the error signal is within the permissive level. In the embodiment shown in FIG. 1, the signal processing unit 10 also checks whether the error signal deviates from the rated value by a too high or too low output signal level. Of the four outputs 10a. 10b. 10c and 10d indicating the status of the signal processing unit 10 indicates the first too low, the second acceptable (lying within the permissible area) and the third too high, while the fourth output outputs a signal suitable for remote indication of the fault; thus, the remote indication, like the signal supplied to the network 12, provides information about an unacceptable fault without determining it. The operation of the logic network 12 can be described in more detail with the aid of figure 2. In the given node, the first and second units I and II are connected to the network 16 by means of the second directional link members 14 and 14, with the same internal connection. At the same time, however, only one of them can be found in the operating state while the other is on standby. That is, in one of them, at the output 12e of the logic network 12, there is a logical level that causes the switch 13 to close while the other is at the output 12e a logical level that causes the switch 13 to open; this must also be ensured if both units I and II are simultaneously operating at the same time if one unit has to be connected to the network, in the latter case, of course, capable of operation. However, if both units I and II are correct, it must generally be ensured that, until the fault has been rectified for the duration of operation, these units are disconnected 16, resulting in consumers connecting to both I and II units cannot follow the program . Such functions can be achieved as described below.

If the first unit I in operable condition is connected to the network 16, as in the case shown in FIG. 2, another logical network terminal 12b of the unit 1 will get a logical level to the next logical network input 12b 12. unit II, which outputs the output 12e of the logic network 12a of the unit IIa which causes the unit to disconnect from the network independently if the second unit II is operable or not. If the system start-up is another logical network terminal 12d of the first tier 1, it is connected to the next logical network input 12b 'of the second unit II. then, when the two units 1 and 2 are operable, the first unit I is connected to the network 16, its terminal 12b is not receiving any blocking signal, while the blocking signal is fed to the terminal 12b 'of the unit II. In the case of damage to the first unit I, no blocking signal can be applied to the other terminal 12da in the logic network 12 of the unit II, while the faulty unit I is disconnected from the mains 16, the second unit II is connected to the network. because the blocking signal is no longer supplied to it. 229 950

However, if one of the I or IIs fails to connect due to a malfunction, the operator will switch on the switch K as soon as the program failure is observed. As a result, the DC power supply U is connected to terminal 12d of the logic network.

1C1 12 of the first unit 1, which in this case does not operate as a signal output but input, the level having an effect on the logic 12 that the switch Ua causes the defective signal to be applied to the directional signal despite the fault signal coming up to the signal processing stage 9 a coupler 14, thereby enabling a rapid determination of the type and location of the defect. Another output 12c of the logic network 12 serves to indicate the status. At this output, the signal is only when, as a result of the appropriate output state 12e, the unit has connected to network 16 either because it is working normally or because the network connection operator has caused the switch K to be triggered. that the connection to the line only takes place after the transition phenomena in the level control. It follows from the above description of the function that the involvement of the invention improves the regulatory process in many ways. In contrast to the known methods, the solution according to the invention ensures that the unit is disconnected from the grid even if automatic control is in order, but the level increment is so high that the controlled signal exceeds the permissible nominal value. If there is no disconnection in this case, the unit would create a - 13

229 BM signal, although of dubious quality, but at the same time the reception units in the network 16, especially when transmitting the color hotel signal, would be useless. Such protection has not yet been created by any known solution.

The described solution of the signal processing unit 10 allows various other uses of the fault indication. While in the intervention of a servant, only a yaw-out indication is needed, the unit status outputs allow for more detailed information, with automatic control being able to? already by means of an operator or unit operator that does not form part of the invention (possibly by processing fault signals in the processor or by controlling various control elements and remote indications) to more quickly determine the defect and remove it. For example, if the outputs indicating the statuses 10a, 10b, 10c 10d in a row will indicate too low a level, a normal level, a too high a level and, for remote indication, only the presence of a fault, then most likely the signal coming to the output 10a this is a defect in the antenna amplifier which is connected upstream of the input divider 11 However, if the signal reaches the third output 10c. indicating the volume of the unit, the control element is likely to be defective in the preamplifier 2. Although the possible signals may also be due to other defects, the complex processing of the various signals allows for an analysis to determine whether or not the likely probable sources of failure are negotiated and In this case, other possible sources of faults must be checked. 14 Asiss

It has already been stated that the disadvantage of the prior art solution was the reduction of the reclosing level, even up to 10-15 dB. By turning the control signal through the first directional coupler, the deceleration range of the deceleration should be 2 to 3 dB, so that the connection limits on the conduit, respectively disconnection, are much more precisely defined, since the described oscillation process cannot The result is that, due to the known properties of the directional link element, the branching signal has theoretically zero and in practice virtually no 1β switches.

Claims (2)

- 15 - SUBJECT OF INVENTION A circuit for multichannel signal transmission systems, for example, for common antenna systems, wherein a plurality of signal sources from lower main channel units, such as various frequency converters and / or common antenna system power amplifiers, may be connected to the system, as well as automatic operation state control in a node and maintaining a prescribed operating condition, or alternatively to resume it at the level of the signal source output level, including a control circuit level connected to the signal source preamplifier, a hot reserve switching element, and suitably equipped with one or a plurality of state indicating elements, characterized in that a directional coupler (5), a switch (ij) and a switch (ij) are provided between the output (15a) of the signal source (15) and the corresponding node (16) of the signal transmission system; second directional a vaso-member (14), between any node (17) of the most suitable output (17 &) connected to a controlled preamplifier, and a control input (13a) of the switch (13), a unit (ΐθ) is connected in series, for a signal processing, a delay member (11) and the logic network (12, 2) The connection according to claim 1, wherein the signal processing unit (1o) is provided with outputs (10a, 10b, 10c, 10d) indicating operating states (e.g., correct level, faulty level exceeding a prescribed value) , a level below the prescribed value) and said outputs (10a, 10b, 10c, 10d) are connected to inputs of other indicating devices and / or other signal processing means. 228 898 3. The wiring according to claim 1 or claim 2, characterized in that the logical network (12) of the main channel unit (i) connected to the nodes is connected to a logical network of another main channel unit (s) connected to the same node, namely such that the other logic network port (12d) connected by the first input (12a) jtta of the delay member (11) of its own main channel unit 11 is connected to the first logical network (12b *) input of the second main channel unit (li), while another output (12c) is connected to an indicator, a direct voltage source (U) is connected via another terminal (12d) via jg switch (K). xC 2 drawings