EP0589845A2 - Device for interconnecting a plurality of electrical circuits to an audio bus system carrying a plurality of audio-signals - Google Patents

Abstract

An electrical circuit arrangement for processing analog electrical signals, particularly in the acoustic low-frequency range, is generated by the fact that the output signals of first function elements (f1, f3, f5, f7, f9) are selectively connected to electric conductors of a bus (13) without hardware change in accordance with their circuits by means of networking elements (d). The conductors of this bus (13) are then selectively connected to the inputs of second function elements (f7, f9, f11), selected by networking elements (m). The connecting is effected by means of a number of analog multiplexers (m) and a number of analog demultiplexers (d), using a current bus, the input of each demultiplexer (d) and the output of each multiplexer (m) following or, respectively, preceding the output (a) or, respectively, the input (e) of the relevant function element (f1, f3, f5, f7, f9, f11) of the relevant circuit module (1, 3, 5, 7, 9, 11). Different circuit arrangements can thus be implemented on standardised boards. Due to the freely selectable networking, it is possible to check individual and interconnected function elements for their operability by connecting a test source and a test detector. An advantage of the circuit arrangement according to the invention lies in the fast and unproblematic change in the networking of the function elements (f1, f3, f5, f7, f9, f11) and in the rapid modification of the function circuits which can be achieved by means of the circuit arrangement. There are no hand-wired customer-specific circuit arrangements, since standardised boards can also be used in these cases. <IMAGE>

Description

The invention relates to an electrical circuit arrangement according to the preamble of patent claim 1, a method for producing the circuit layout according to the preamble of patent claim 9 and a method for functional testing according to the preamble of patent claim 11.

Analog electrical signals can be generated, amplified, attenuated, filtered, mixed, etc. by means of functional circuits, implemented by electrical circuit arrangements, using active and passive functional elements. The circuit layout of a circuit arrangement is, for. B. constructed as printed circuits, multilayer, multiwire circuits, etc. The layout is often optimized using a computer. Subsequently discovered errors or circuit changes require a patchwork on the circuit layout already created or its new production. Circuit layout, manufactured according to special customer requests, is preferably produced in so-called 19 '' technology by hand-wired functional elements due to the small quantities. This type of production is complex and prone to errors.

A circuit arrangement is understood to mean the functional electrical networking of functional elements, such as are described, for. B. is shown in an electrical circuit diagram. Functional elements can be signal sources, attenuators, filters (high, low and bandpass), amplifiers, detectors, etc. The hardware arrangement of the individual functional elements takes place in a so-called circuit layout z. B. on circuit boards. In the known electrical circuits, a hardware layout was created for each circuit arrangement. This layout had to be changed again and again in the event of deliberate errors or changes to the functional elements to be used.

Networking elements are elements with which a line can be releasably connected to another line, selected from a bundle of lines or a line bus. The selection is made by a control with an electrical z. B. coded signal. Voters (especially in telecommunications technology), demultiplexers and multiplexers are used as networking elements. A typical area of application for networking elements is communications technology, in which telephone subscribers have to be connected to one another. The connection to be established is always made from a point A to a point B. It is also known from telecommunications technology to switch on filters in a wiring harness. Only a yes-no function is possible. Either the filter is in the wiring harness or not.

DE-A 36 15 981 describes an electrical circuit arrangement in which electrical functional elements (fully parametric audio filters, delay units) each have a multiplexer (n in 1) and a demultiplexer (1 in n) connected upstream or downstream. The number of signal lines depends on the number of input signals to be processed. A first demultiplexer each selects one of the signal lines and switches a first functional element into this signal line. The following functional elements are synchronized by means of a microcomputer which controls the switching positions of the demultiplexers and multiplexers. The connection and the hardware structure of the circuit arrangement are designed such that the connection takes place in each case in the only selected signal path.

However, the object of the invention is to enable different circuit arrangements without hardware changes to the circuit layout.

The object is solved by the claims.

A networking possibility of functional element outputs with the input of each functional element using networking elements means that the networking structure of the functional elements can be changed quickly and easily, i. H. the function of the circuit or only the creation of a desired function or functions, as well as a rapid change in the circuit function achievable with the functional circuit. The selected inputs and outputs of the functional elements are preferably networked by means of multiplexers and demultiplexers as network elements.

Furthermore, if all signals are present as current signals, their problem-free superimposition on a signal line is possible, which is particularly the case with acoustic signals from e.g. B. several microphones for a speaker or a recording unit is advantageous.

Another advantage of the invention results from the simple design of the printed circuit boards to be populated. Therefore, only a standardized circuit arrangement in a standardized circuit layout is required for the most diverse functional circuits, then the special linking of the inputs and / or outputs of the circuit modules containing the functional elements takes place in order to achieve the desired function with the demultiplexers and multiplexers. There is no need for hand-wired circuits because standardized circuit boards can also be used for circuits with customer-specific requirements.

Fig. 1

ein beispielsweises elektrisches Blockschaltbild einer Funktionsschaltung, welche mit der in

Fig. 2

dargestellten Schaltungsanordnung verwirklicht ist,

Fig. 3

ein Beispiel eines Spannungsstrom-Wandlers,

Fig. 4

eine Vervielfältigung eines Stromsignals in k gleiche Stromsignale,

Fig. 5

ein Beispiel einer Übertragung von Stromsignalen eines Strombusses auf einen weiteren zweiten Strombus der Schaltungsanordnung und

Fig. 6

eine Schaltungsanordnung mit einem Strom- und einem Spannungsbus für eine akustische Beschallung.

Examples of circuit arrangements and of the method are explained in more detail below with reference to drawings. Show it:

Fig. 1

an example of an electrical block diagram of a functional circuit, which with the in

Fig. 2

circuit arrangement shown is realized,

Fig. 3

an example of a voltage current converter,

Fig. 4

a duplication of a current signal into k identical current signals,

Fig. 5

an example of a transmission of current signals of a current bus to a further second current bus of the circuit arrangement and

Fig. 6

a circuit arrangement with a current and a voltage bus for acoustic sound.

The electrical functional circuit for analog electrical, acoustic LF signals shown as an example in FIG. 1 has a plurality of circuit modules, namely two input modules 1 and 3 , a signal source 5 , a filter module 7 , which filters the signals of the input module 1 and the signal source 5 , and another Filter module 9 , which filters the output signal of the input module 3 and as output module, a buffer 11 , which brings the output signals of filter modules 7 and 9 to the +6 dBm value usually used in "ELA" (electro-acoustic) technology. The analog LF signals to be processed with the circuit are between 20 Hz and 25 kHz. The circuit arrangement with the circuit modules 1 , 3 , 5 , 7 , 9 and 11 is shown in FIG. 2 , the "signal-carrying" connecting line parts being drawn in thick lines for better understanding. There are four different circuit module types in FIG. 2 , namely input modules 1 and 3 , a signal source 5 , two function modules 7 and 9 , an output module 11 and a current bus 13 for the electrical connection of the circuit modules to one another. These four types of circuit modules can be understood as basic modules for other circuit arrangements to be implemented in a circuit layout.

An input module is understood to mean a circuit module whose input is connected to an external element, such as, for. B. with a microphone, a sound pickup on an instrument, a sound player, etc. and its output is connected to the power bus 13 and thus to another input of a function module of the circuit arrangement. Function modules are understood to mean circuit modules with an input and output which are connected to other function modules, input or output modules via the current bus 13 . Signal sources are circuit modules with no input because they generate their own signal, such as B. clock, noise, pilot tone sources, generators for accompanying music, etc., the output of which is also connected via the power bus 13 to one of the other function modules. The input of output modules is via the current bus 13 to the output of one of the other function modules and their output to an external element, such as. B. customer-specific commercial goods - amplifier, tape recorder, external filter, mixer, external signal delay, etc., connected. The current bus 13 is an arrangement of a plurality of electrical conductors which are insulated from one another, suitable for signal transmission.

All circuit modules have a similar structure, consisting of a multiplexer m or a demultiplexer d and a current-voltage or a voltage-current converter x or y . Outputs or inputs which are connected to external components can be blocked with a galvanic isolating element g . Each multiplexer m and each demultiplexer d has a plurality of coding connections 15 and an “enable” connection 17 which connects the relevant multiplexer m or demultiplexer d activated for a switchover of its "switch position". The coding connections 15 and the “enable” connection 17 are connected to a control unit 19 . The number of coding connections 15 depends on the number of available connection options with the conductors of the power bus 13 . The electrical function, such as the generation of an electrical signal in the signal source 5 , filtering of the signals in the switching modules 7 and 9 , etc., is carried out in each case by a functional element f in the relevant circuit module. The index i of the functional elements f _i indicates the affiliation to the relevant circuit module with the reference number i .

The number of conductors of the current bus 13 depends on the circuit structure. If there are n modules, all of which are to be connected in series, n-1 conductors are required. If two of n modules are connected to each other, n / 2 power bus conductors are required. If the outputs of two modules of n modules are connected to a third module, n / 3 power bus conductors are required. To achieve the greatest possible variety of circuits for a standardized construction of a circuit board, it should therefore be sufficient to use n / 2 current conductors, as shown in FIGS. 1 and 2 for only 6 circuit modules. The design of a standardized circuit board should preferably have 32 circuit modules with 16 bus lines, these Numbers are adaptable to certain requirements.

To produce the layout of a circuit arrangement, a circuit board with n connection sockets for a total of n signal sources, input modules, output modules and function modules is produced, wherein preferably a raster is selected so that both signal sources, input and output modules and function modules can be connected in any order. Each terminal base is connected to all power bus conductors.

The circuit board produced in this way is now equipped with the required signal sources, input, output and function modules and with the control unit. After equipping, the inputs of the input modules and the outputs of the output modules are connected to the external elements - microphone, power amplifier, etc. - by means of a connector with a signal line. The desired “switch positions” for the desired circuit function are then generated by selecting the individual multiplexers m and demultiplexers d via the Enableleitung 17 and sending out a corresponding coding via the coding lines 15 .

Instead of making the connection links by coding via the control unit 19 , a solder connection of the H (high) - L (low) values corresponding to the coding can also be carried out.

Transformers are used as galvanic isolating elements g .

FIG. 3 shows a voltage-current conversion, for example. In this version, two Operational Trans-Conductance Amplifiers (OTA) 23 and 25 are used, which are located on one chip and therefore have very good synchronization. The OTA 23 has a fixed bias current 26 ( I _bias ) and that applied to the resistor 27 Output signal is used exclusively for linearization of the overall characteristic, which reduces the harmonic distortion. The bias current 29 from OTA 25 can be variably set by the control unit 19 , as a result of which the output level is set over a wide range, which is particularly advantageous in the case of volume control.

Instead of building up a circuit arrangement for analog current signals, one can also be built up for analog voltage signals, in which case, however, the voltage current transformers are omitted and the simple signal superimposition by a galvanic connection is no longer provided.

In addition to the previously described advantage of unlimited signal mixing, the use of impressed current signals results in a high suppression of interference signals which could be on the electrical "0 reference point". It is therefore possible to carry out an asymmetrical transmission instead of the usual symmetrical transmission of the signals, in which case only half the number of switching points otherwise required is required. As a further consequence of the current injection, the signal quality is independent of any non-linear behavior of the signal switches. As a result, inexpensive semiconductor switches can be used without having an adverse effect on the distortion factor. It is also advantageous that the signals with the voltage value "virtually zero" can be carried on the signal path, as a result of which extremely high crosstalk attenuation between the signal paths is realized. In a circuit arrangement with current injection, external signals can only be interspersed by capacitive influence; an inductive influence has no effect. Differences in potential due to long cable runs are less critical in the case of an impressed current signal than asymmetrical voltage signals.

The circuit arrangements described above can not only be used in the LF range, but can also be used in other frequency ranges.

The use of signal currents in a circuit has the advantage that any current signals can be superimposed by a link in a node or by connection to a conductor of the current bus 13. However, a branching of a current signal to several inputs of functional elements is not readily possible, since if the branches were to be branched, assuming the same input resistances, the level of the current signal would be reduced according to the number of inputs.

In order to avoid a signal distortion in signal height reduction when dividing the current signal, the current signal in question is converted on a line 33 , as shown in FIG. 4, into a voltage signal by a current-voltage converter 35 . The output line of the current-voltage converter 35 with the voltage signal is then divided into k line branches in a line branch 37 . A voltage signal of the same magnitude corresponding to the voltage signal is now present on each of these k line branches. These voltage signals are then k ... transformed again by k-voltage current transformer 39₁, 39₂, 39 _k in the same current signals. These current signals can now be impressed on selected conductors of the current bus 13 ; however, as shown in FIG. 5 , they can also be transferred from a first power bus 41 to a second power bus 42 . The second power bus 42 can then e.g. B. be looped with other boards in a rack to transmit signals from one board to another.

Instead of a knot-shaped branch, as shown in FIG. 4 , the line branch 37 can also be designed as a voltage bus 43 , as used in FIG. 6 be.

FIG. 6 shows a functional circuit example of an acoustic sound system with a number of b microphones 45 1 to 45 _b with b-connected preamplifiers 46 1 to 46 _b , each of which emit a current corresponding to the signal level to the power bus 47 . The conductors of the current bus 47 can be selected via a number c of multiplexers m , the outputs of which each go to the input of a current- voltage converter 49 1 to 49 _c . The output of each current- voltage converter 49 1 to 49 _c leads to only one conductor of the voltage bus 43 . All conductors of the voltage bus 43 are, provided there are no predetermined preferences, now connected to the inputs of a number of multiplexers 51 1 to 51 _h , the outputs of which are connected to one of the loudspeaker power amplifiers 53 1 to 53 _{h of} the loudspeakers 54 1 to 54 _h . Is z. B. a loudspeaker 55 assigned in terms of circuitry, it can be connected directly bypassing the voltage bus 43 with a current-voltage converter 49 _x .

In addition to the microphones 45 1 to 45 _b , any signal sources 57 , such as alarm devices (fire, ventilation, air conditioning, ...), speech generators, etc. can be connected to the power bus 47 . The signals from the signal sources 57 and the microphone signals are processed with a number q of functional elements 59 1 to 59 _q , which are connected via demultiplexer d and multiplexer m , analogously to the functional circuit from FIG. 2 . In order to depict that both the inputs and the outputs of the functional elements 59 1 to 59 _{q lead} to the current bus 47 , this is the functional elements 59 1 to 59 _{q drawn in a} U-shaped manner .

Without changing the circuit layout, z. B. sonication of all or selected rooms in department stores, schools, hotels, looping in and controlling external devices such as filters, equalizers, speakers, etc. via input modules and buffers (output modules) f₁, f₃ and f₁₁, an alarm is sent out in all or selected rooms using a signal source analog f₅, .... When sonicating rooms z. B. is established between a call station and corresponding speakers on site, both groups and collective calls can be carried out. It can now be spoken from a central station or from several stations.

The construction of the individual connection paths and the signal processing carried out or to be carried out in the path by means of a plurality of functional elements can take place in a controlled manner via the control unit 19 . Software-controlled priorities for individual priority connections can also be introduced.

Because of the simple circuit configuration that can be changed by the control unit 19 , it is possible to check the functionality of the individual functional elements, particularly when they are not being used at the moment. To check the functional elements, a pilot tone from a pilot tone source, such as. B. the signal source 5, via its demultiplexer connected to a signal-free line of the power bus, removed from this line via the multiplexer of the functional element to be tested and processed by the functional element to be tested. The demultiplexer connected downstream of the output of this functional element now switches to a free conductor of the current bus, which is then connected via a correspondingly connected multiplexer to a test detector which checks the signal transmitted by the functional elements to be tested.

In this way, one functional element after the other can now be checked. It is also possible to connect several functional elements in series be checked for step as well as the function of the entire networked circuit arrangement.

A pilot tone source can also be integrated in the input modules - usually with an acoustic circuit microphones with input amplifier. This pilot tone source always gives a pilot tone as soon as there is no signal and causes the sequential switching or switching on of the corresponding functional elements via a control line (not shown) to a test control device (not shown).

If a defective element is determined by the functional element check, another signal path is switched with the control unit 19 while the defective functional element is exchanged.

With the above functional circuit, realized with the circuit arrangement described above, different microphone units can now be connected to selected loudspeakers for sound reinforcement in different rooms. However, additional data and information can also be processed, specifically queried and distributed with this circuit arrangement. So z. B. fire monitoring in individual rooms with appropriate automatic fire detection can be achieved by targeted selection of appropriate functional elements. It can also be used to carry out additional climate controls for the rooms, etc.

Claims (11)

Electrical circuit arrangement for several circuits differing in their electrical functions for analog electrical signals, in particular in the acoustic NF range with several one input and one output (e, a) or only one output (a) having functional elements (f 1, f 3, f 4 , F₇, f₉, f₁₁), characterized in that each input (e) F₇ of the functional elements (, f₉,) f₁₁ with at least one of which (f₁, f₃, f₅, F₇, f₉, f₁₁) outputs (a) cross-linking elements ( d, m) can be selectively connected so that the required circuit functions can be selected by means of the networking elements (d, m) by selecting from any networking options for the inputs and outputs (e, a) of the functional elements (f₁, f₃, f₅, f₇, f₉, f₁₁ ). can be produced without hardware changes to the circuit layout. Electrical circuit arrangement for a plurality of circuits for analog electrical signals which differ in their electrical functions, in particular in the acoustic LF range with a plurality of functional elements (f 1, f 3, f 4, f 4, f 4, f 1 2) having one input and one output or only one output, characterized in that each output of the functional elements can be selectively connected to at least one of their inputs with networking elements (d, m) , so that the required circuit functions by selecting from any networking possibilities of the inputs and outputs (e, a) of the functional elements by means of the networking elements (d , m) can be produced without hardware changes to the circuit layout. Circuit arrangement according to Claim 1 or 2, characterized in that the networking elements first networking elements, in particular demultiplexers (d) , with one input and at least x outputs, and second Networking elements, in particular multiplexers (m) , have one output and at least x inputs, the number x corresponding to the number x of the number of an input (e) for electrical current signals and the number x of the functional elements having an output (a) for voltage signals, each output (a) the functional elements (f₁, f₃, f₅, f₇, f₉) with the input of one of the first networking elements (d) , each input (e) of the functional elements (f₇, f₉, f₁₁) with the output of one of the second networking elements (m ) , each of the outputs of the first networking elements (d) can be connected to each of the inputs of the second connecting elements (m) . Circuit arrangement according to Claim 3, characterized by a bus (13) with at most x conductors, each of the outputs of the first networking elements (d) and each of the inputs of the second networking elements (m) being connected to only one of the conductors of the bus. Circuit arrangement according to Claim 4, characterized in each case by a voltage current (y) or current voltage converter (x) connected downstream of the output (a) and / or the input (e) j of the functional element (f₁, f₃, f₅, f₇, f₉, f₁₁ ) . Circuit arrangement according to one of claims 1 to 5, characterized by at least one control device (19) connected to the networking elements (d, m ) for controlling their switching positions. Circuit arrangement according to one of Claims 3 to 6, characterized by second functional elements (35) for converting a first current input signal into a first voltage output signal and a multiplication element (37) for multiplying the first voltage output signal into a plurality of analog second signals Voltage output signals. Circuit arrangement according to claim 7, characterized by a respective voltage current converter (39₁, ..., 39 _k) per second voltage output signal, and a each voltage current converter (39₁, ..., 39 _k) downstream demultiplexer (d) to the to the voltage current converter (39₁ , ..., 39 _k ) generated second current signal to a conductor of the first bus (13) or to a selected conductor of a second bus (42) . A method of manufacturing a circuit arrangement according to claim 1, characterized in that each output (a) each one or more functional elements (f₁, f₃, f₅, f₇, f₉, f₁₁) together from a first selection necessary for a first functional circuit from the total amount of existing functional elements (f₁, f₃, f₅, f₇, f₉, f₁₁) each with an input (e) of another functional element (f₇, f₉, f₁₁) of the first selection by means of networking elements (d, m) in a first networking assignment and required change of the functional circuit, the networking of the inputs and outputs (a, e) with the networking elements (d, m) in a second networking assignment, a second selection of functional elements from the total number of functional elements and their networking in accordance with the required new functional circuit without hardware changes to the circuit layout only by controlling the networking elements. A method for producing a circuit arrangement according to claim 2, characterized in that each input each one or more functional elements together from a first selection necessary for a first functional circuit from the total amount of existing functional elements, each with an output of another Function elements of the first selection are connected by means of networking elements in a first networking assignment and, if the function circuit is changed by networking the inputs and outputs with the networking elements in a second networking assignment, a second selection of functional elements from the total number of functional elements and their networking in accordance with the required new one Functional switching without hardware changes to the circuit layout is carried out only by controlling the networking elements. Method for functional testing of the functional elements (f) used in an electrical functional circuit of the circuit arrangement according to claim 4, characterized in that a test signal to be checked by a test detector is sent from a test signal source by the functional element to be tested, in which the test signal is sent to a first conductor of the bus (13) , the multiplexer (m) upstream of the input of the functional element to be tested on the first conductor, the demultiplexer (d) downstream of the output of the functional element to be tested onto a second conductor of the bus (13) and the test detector via a series input upstream of its input Multiplexer (m) is connected to the second conductor.

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