FR2789540A1 - Control method and unit for loudspeakers in sound system uses inaudible signals from emitter and loudspeaker to trigger visual or audio alert system - Google Patents

Abstract

Acoustic signals emission source (22) is linked to amplifier (21) connected to loudspeakers (HP). FSK emitter (3) sends modulated signals, inaudible to man, to amplifier. Inaudible signals sent by loudspeaker attached to FSK emitter are captured by microphone (12) and converted in parallel signals by converting receiver FSK (15). Those signals trigger visual or audio alert to user. An Independent claim is also included for the description of control unit for speakers.

Description

- 1 - Method and device for controlling the loudspeakers of a

  sound system. The invention relates to a method and a device for checking the proper functioning of the loudspeakers and for identifying the different loudspeaker / amplifier connections of a sound installation of the kind comprising a source of emission of acoustic signals connected to the at least one amplifier itself connected to a plurality of loudspeakers, the invention being more particularly applicable to installations comprising several amplifiers

  each of which is connected to a plurality of speakers.

  This invention is a maintenance and investigation tool for public address networks with general call broadcasting. It can be applied advantageously to public address systems in companies and centers

  public or private activities, in which a very large number of high-

  speakers for the dissemination of messages or alarm signals must guarantee operational safety, for example in the following situations evacuation, danger, dissemination of orders, transmission of information, summons,

  search for people, musical atmosphere, etc ...

  For example, on a nuclear site, several independent installations can consist of several buildings. Such sites

  can cover up to 20,000 m2, and group together around fifteen buildings.

  All of the premises set up inside these buildings must be soundproofed to broadcast different types of addressable messages in areas

distinct geographic areas.

  These zones can be broken down into three sectors: - an exploitation type sector where the general calling network allows staff to communicate messages of the "people search" type; a zone extension type sector to reach the administrative premises and broadcast a general call; an alarm type sector relating to the two previous zones which must broadcast safety and evacuation instructions. Due to the high level of security of these public address systems, periodic maintenance, for example monthly or bimonthly, must verify the proper functioning of each speaker. For example, an installation

  described as above can have a fleet of 600 to 1000 loudspeakers

  0 or more speakers distributed over all the buildings on the site.

  Currently, to carry out the maintenance of a public address system of the aforementioned type, maintenance technicians must individually check the proper functioning of each speaker, regardless of the environment of the place where it is installed. These places can be of different types, for example: administrative offices, meeting rooms, public corridors, radioactive cells, operating areas, dining halls, etc. All these places can pose specific problems during the control of the loudspeakers which can last several days given the large number

  speakers. Indeed, to carry out the maintenance of the various

  speakers of an installation, it is necessary to use them in a conventional manner, in

  making them emit a sound, in a frequency band audible by humans.

  This requires the intervention of two technicians: a first manipulator technician emits an audible signal which is transmitted by the speakers, the second verifying technician moves opposite each speaker to

  whether or not to listen to the corresponding sound of the sound signal emitted, depending on whether said loudspeaker

  speaker works normally or not. Maintenance as carried out to date entails the following disadvantages: - noise pollution for staff or other people who are in the premises or on the premises where the loudspeaker control is operated (administrative staff, meeting rooms , and also for

  the technicians responsible for testing the speakers).

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  A relatively long intervention time for technicians,

  arising from the need to carry out the census of high-

  speakers and their location according to the amplifier used.

  The mobilization of at least two manipulator and verifier technicians, the first emitting, at the source, the sound signal, the

  second, at the reception, controlling the transmission of the latter.

  In addition, depending on the needs of the site and the development of the installation over time, loudspeakers are sometimes added during the construction of new offices or premises, thanks to a very simple parallel connection. Thus, an original plan quickly becomes obsolete. Also, this type of connection is often done without taking into account the nominal power of the amplifiers that power the speakers. This overload of the amplifiers can, in the event of prolonged use, lead to deterioration of the latter and put them

quickly out of service.

  The control intervention as currently carried out is tedious, long, delicate, not precise and annoying for the personnel, which, in general, does not lend itself at all to the objectives of preventive maintenance or

  correction of the speakers of any sound installation.

  For example, on a nuclear site, the intervention must be rapid and effective.

  To solve the problem of noise nuisance, the document EP0607693 describes a method for diagnosing an electrical connection between a power amplifier and a loudspeaker in a communication system, comprising: - the initialization of a diagnosis by selecting a predetermined entry on a control unit; - generation of a predetermined tone signal in response to the selected input; - the application of said tone signal to the amplifier; - detecting the output of said amplifier; - the variation of the level of said tone signal; - monitoring the level of the tone signal at which clipping occurs; and indicating whether clipping begins within a predetermined range of tone signal levels. This method, more particularly intended for the functional test of the radio installations of vehicles, has the major drawback of not allowing an individual verification of the operation of the loudspeakers of the installations, so that if the latter do not function, their state

  io faulty is not detectable.

  An object of the invention is therefore to remedy the drawbacks of

  current methods and techniques for verifying the operation of loudspeakers

  speakers of sound installations.

  According to the invention, this objective is achieved by means of a method and a device according to which one transmits and sends, by means of a transmitting device comprising an FSK transmitter, serial signals modulated on frequencies inaudible to humans except at least one amplifier connected to a plurality of

  speakers, and that the inaudible serial signals from each speaker

  speakers are picked up by means of a portable converter receiving device comprising a microphone and transformed, by means of a FSK converter receiver included in said converter receiver, into usable parallel signals which are used to activate a signaling means perceptible by the operator, this signaling can be visual and / or audible, which makes it possible to detect defective loudspeakers and to check the connections

amplifiers / speakers.

  Thanks to the method and the device according to the invention, it is possible to quickly and easily check the operation of the various speakers and the

  amplifier / speaker connections for public address systems.

  On the other hand, the diffusion by the loudspeakers of inaudible signals for the human ear, does not generate any noise nuisance for people

  located near said speakers.

  In addition, the cost of maintaining the installations is significantly lower, since it only takes one technician-operator to generate the signals, and

  check the loudspeakers.

  Thanks to the presence of a sensitive microphone in the decoder receiver

  or converter, the operator technician can also check loudspeakers.

  speakers previously inaccessible, for example when installed too far

I0 from the ground.

  According to another characteristic arrangement, applicable to sound installations comprising several amplifiers each of which is connected to a plurality of loudspeakers, the method and the device according to the invention are remarkable in that the inaudible serial signals transmitted by the FSK transmitter are binary coded, by means of a code encoder and a coding wheel, according to the amplifier to which the transmitting device is connected, and in that the inaudible coded serial signals emitted by the speakers connected to the output of this amplifier are transformed, by means of a code decoder fitted to the converter receiver, into stable parallel signals used to activate a

digital display.

  Thanks to this arrangement, it is possible to identify the amplifier to which the loudspeaker of the sound installation is connected, which greatly facilitates

  the establishment of a map of said installation.

  According to another characteristic arrangement, the method and the device of the invention are remarkable in that the transmitting apparatus or the transmitting-encoding apparatus comprises a switcher whose input is connected, on the one hand, to the source d emission of acoustic signals from the installation making it possible to broadcast general call signals, and on the other hand, to the FSK transmitter, and the output of which is connected to the amplifier connected to said transmitting device, this switch being configured to prioritize general call signals to said amplifier.

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  Thanks to this characteristic arrangement, low frequency general call signals are guided in priority to the amplifier to which the transmitting device is connected, even if the latter emits inaudible serial signals, which allows the signal transmission system to '' general call (evacuation orders, search for people, etc.) to remain operational during the operations of

speaker control.

  According to another characteristic arrangement of the device of the invention, the decoder receiver or converter receiver device includes a laser pointer disposed near the microphone, so as to emit a laser beam in

  0o a direction identical to that of the pick-up field of said microphone.

  Thanks to this arrangement, the checking operator equipped with the portable converter receiving device can precisely orient the microphone of

  this device towards the speakers to be controlled.

  The above goals, features and benefits and more

  will emerge more clearly from the description which follows and from the attached drawings in

which:

  - Figure 1 is a schematic view of the high control device

  speakers according to the invention, this diagram illustrating more particularly the block diagram of the transmitter encoder; - Figure 2 is a schematic view showing more particularly the

  block diagram of the decoder receiver or converter receiver.

  Reference is made to said drawings to describe an advantageous form, although in no way limitative, of making the device and implementing the

  loudspeaker control method according to the invention.

  The loudspeaker maintenance method according to the invention consists in transmitting to the amplifier or to each of the amplifiers 21 of the sound installation, a coded signal specific to each amplifier. These signals, amplified by the amplifier to which they are addressed, are inaudible at the output of the speaker battery 20 connected to the latter and consisting of a parallel connection of several HP speakers. The coded signal varies for each

  amplifier, so that the inaudible signal collected at the output of each loudspeaker

  speaker in working condition, is different depending on the amplifier to which it is connected. On the other hand, in the case where the controlled loudspeaker is not in working condition, no inaudible signal will be detected at its output. It is thus possible, by this control procedure, to know the operating state in which each speaker is located, and to determine which amplifier is

  connected each of the controlled speakers.

  To implement this method, a device consisting of at least two types of device is required, namely: a first device called a "transmitter encoder" 23 transmitting the inaudible signal coded according to the amplifier 21 to which it is connected, connected, upstream to a low frequency general call signal transmitter 22, known per se, and, downstream, to the amplifier 21; there are as many transmitting devices or encoding transmitting devices 23 as there are amplifiers 21, each transmitting device being connected to an amplifier; - a second autonomous and portable device called a “decoder receiver” 24 or “converter receiver” decoding the inaudible signal into a signal perceptible by the operator, preferably visible, (digital display, for example) and, where appropriate, into an audible signal , when the operator stands in front of a loudspeaker in working condition

  and directs the sensor of said device towards this speaker.

  To carry out the maintenance test, it suffices first of all to switch on the various encoder transmitters grouped in the bay

installation sound system.

  Each encoder transmitter 23 can advantageously consist of a set of at least four functions, and preferably five functions: First function: a general call monitoring function or stage or switch 01 connected, upstream, to the low frequency general call signal 22 and to the inaudible coded signal transmitter described below, and, downstream, to the amplifier 21. The switch 01 is constituted by an electronic circuit or assembly, known per se, operational amplifier type which gives priority to the general call signal. This electronic circuit being configured to analyze the low frequency general call signal emitted by the source of acoustic signals of the sound installation, parameterized by a minimum amplitude, and to transmit in priority, said general call signal to the amplifier 21. In the case where the encoder transmitter is defective or broken down, there is a mechanical switchover of the general call signal to a direct electrical link (a relay) of

  1o the general call 22 to the different amplifiers.

  Second function: the coded signal is a function of the amplifier to which the device is connected, this thanks to the presence of a coding wheel 05 which makes it possible to code the amplifier. The encoder wheel 05 is preprogrammed by the operator by incrementing or decrementing it, that is to say by choosing a decimal or hexadecimal value for each amplifier. This wheel produces a binary signal of several bits (for example 3 bits allowing to code 10 different amplifiers or 4 bits making it possible to code 16 amplifiers

  (In this case, we speak of a "4-bit hexadecimal" encoding wheel).

  Third function: the serial signal sent by the encoder wheel is transmitted to the encoder code 02 which generates a serial signal coded in binary TTL (transistor, logic transistor 0-5 volts), according to the decimal value indicated by the

encoder wheel 05.

  Fourth function: the signal sent by the encoder consists of two identical successive words. A word is made up of 9 bits, between these two words, a space equivalent to 3 bits is sent, which makes a total of 21 bits for the transmission of a code (9 bits + 3 bits + 9 bits ). These 9 bits integrate the 4 variable data bits from the encoder wheel and 5 address bits which are frozen. The time required for the whole cycle is 817 ms (time for 1 bit 38, 88 ms). The "tempo" function 04, materialized by a known electronic timing circuit or assembly, is used to send the chosen code at the desired frequency. This frequency can be configured to play on the number of transmissions depending on the density of the speakers. For an installation where the speakers would be arranged in large numbers and

  close together, the frequency of the delay would therefore be rapid, and vice versa.

  It is understood that the operator technician who travels with the portable receiving device will be able to control a maximum of one speaker every second (a burst of the encoder of 21 bits = 0.8 seconds). Then, this binary coded serial signal, for example of 12 bits, is converted into several inaudible frequencies (below 20 kHz). Preferably, for the new generation speakers, the two inaudible frequencies chosen to convert the two binary states 1 and 0 are 18.5 kHz and 19.5 kHz, taking into account the fact that a difference of at least 1 kHz between the two frequencies is desirable. The transmitter stage FSK 03 therefore modulates the serial signal from encoder 02 on two frequencies 18.5 kHz and 19.5 kHz, as a function of the two binary states 1 and 0. This signal inaudible to the human ear is directed to the switch function 01 to be sent to the input of amplifier 21. The loudspeakers HP then broadcast either the i FSK coded inaudible signal, or the priority low general frequency call signal, and

this automatically.

  For older speakers, the two signal sending frequencies

  can be 15 kHz and 15.5 kHz, respectively.

  Fifth function, by connecting the encoder wheel 05 to a microprocessor card 06 processing and transmitting the binary information generated by said encoder wheel, it is possible to display this information on a liquid crystal screen or LCD display (07). It can thus permanently display the date, time and emission code of said coding wheel. Preferably, each

  transmitter has a backlit LCD display.

  As a non-limiting indication, the encoder transmitter according to the device of the invention is supplied with 12 volts DCC at a transmission frequency of about 20

kHz FSK.

  The decoder receiver or portable converter receiver 24 of the maintenance device according to the invention consists of a set of several

  functions, and, advantageously, at least 6 functions.

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  First function: a first microphone stage includes a sensitive microphone 12 placed at the front of the device 24 and capable of picking up the audible signal inaudible to the human ear, emitted by each loudspeaker to be tested from the battery or column speakers, orienting the decoder receiver in the direction of the speaker to be controlled. Second function: an amplifier stage comprising an amplifier 13 constituted by an electronic assembly or circuit known per se, connected to the output of the microphone 12 and which has the function of amplifying, for example by approximately

  400 times, the amplitude of the inaudible signal picked up by said microphone.

  Third function: a bandpass filter stage comprising a bandpass filter 14 connected to the output of the amplifier 13 and connected to the FSK receiver 15, this filter having the function of attenuating the parasitic frequencies, leaving no

pass that FSK signals.

  Fourth function: once the signal has been purified, at the output of filter 14, the inaudible frequencies chosen during the installation of the FSK transmitter of the first device (for example 18.5 kHz and 19.5 kHz) are transmitted to an FSK receiver 15. This extracts the serial signal from it and transmits it to the decoder stage. Fifth function: The decoder stage includes a code 16 decoder which

  transforms the serial signal into a stable parallel signal.

  Sixth function: the stable parallel signal is exploited by a digital display 17 which makes it possible to indicate the decimal or hexadecimal code chosen and transmitted

by the transmitter encoder 23.

  The code displayed corresponds to that of the encoder wheel and, therefore,

  to the amplifier to which the controlled speaker is connected.

  An advantageous additional function or stage can be added. This function comprises a frequency detector 18 supplying an acoustic vibrator or buzzer, generally called a buzzer 19, connected to the output of the amplifier 13 or of the filter 14, when the latter is present. This montage

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  allows to translate a reception threshold of stable sinusoidal frequencies, for example, above 18 kHz, by an audible signal generated by the buzzer. This function is designed in addition, as a second possible control. In addition, the operator accustomed to a sound control, is less disoriented by this second control, without the resulting sound signal being annoying for the surroundings,

  given the fact that it is punctual and of low intensity.

  The incorporation of a microprocessor card into the circuit of the decoder receiver device also gives the possibility of upgrading the maintenance device. Indeed, it would then be possible to process the results of the control

  loudspeakers ic by a database, to manage the loudspeakers

  speakers tested, or control the length of time spent to perform the

  maintenance of all speakers.

  According to another advantageous embodiment of the converter receiver or decoder receiver, a laser diode pointer 10 is placed near the sensitive microphone 12. It is started independently by a button 11, accessible on the housing. the device. This laser pointer allows the operator technician to orient the receiver decoder precisely in the direction of the speaker to be tested. Its use is particularly recommended for speakers that are difficult to access, some of which can be installed up to 5 m high, due to a directional angle.

  very weak sensitive sensor microphone 12.

  As a non-limiting additional indication, the decoder receiver is powered by four 1.5-volt batteries, allowing it to have an autonomy of about 8 hours with a range of + or - 7 m. It can be contained in a

  ABS housing L = 180 x I = 100 x h = 44/35 mm.

  The maintenance of the loudspeakers is greatly facilitated by the device and the method according to the invention. This device and this method are reliable and practical in their use. It suffices that a single technician turns on each encoder transmitter, then moves from speaker to speaker by "pointing" the receiver-decoder 24 towards each controlled speaker, at least during the time delay, microphone sensitive

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  being directed towards the exit of these. The technician will then be able to read on the screen of his decoder receiver, ie a 0 which means that the receiver is in working order, but that there is no decoded sound signal; either a decimal or hexadecimal value corresponding to the inaudible emission code chosen on the encoder transmitter, and identical to that displayed on the screen thereof. This information allows you to know if the speaker under test is in working order, and if so, to which amplifier it is connected. It is then easy to establish a

  mapping of the entire installation (top connection

  speakers / amplifiers), and if necessary correct the installation if for example

  too many speakers connected to the same amplifier.

  The method and the maintenance device of the present invention therefore make it possible to draw up a map of the speakers of a complex sound system, and jointly, to carry out maintenance of these.

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Claims (15)

REVENDI CATIONS   1. Method for controlling the speakers of a sound installation of the kind comprising a source for transmitting acoustic signals (22) connected to at least one amplifier (21) itself connected to a plurality of speakers ( HP), characterized in that, by means of an FSK transmitter (03), serial signals modulated on frequencies inaudible to humans are transmitted to said amplifier (21), and in that the serial signals inaudible emitted by each speaker (HP) connected to the latter, are picked up by means of a microphone (12) and transformed, by means of an FSK converter receiver (15), into usable parallel signals which are used to activate a signaling means perceptible by the operator,   this signaling can be visual and / or audible.   2. Method according to claim 1, applicable to sound installations comprising several amplifiers (21) each of which is connected to a plurality of loudspeakers (HP), characterized in that the inaudible serial signals emitted by the FSK transmitter (03 ) are coded in binary, by means of a code encoder (02) and a coding wheel (05), as a function of the amplifier (21) to which the transmitting apparatus (23) is connected, and in that the inaudible coded serial signals emitted by the speakers connected to the output of this amplifier are transformed by means of a code decoder (16) connected to the FSK receiver (15) into parallel signals used to activate a display   digital (17) for identifying said amplifier.   3. Method according to one of claims 1 or 2, including the source of emission of   acoustic signals allows general call signals to be broadcast, characterized in that these general call signals are routed first and automatically to the amplifier or each amplifier (21) of -14- 2789540   the sound system, during the control operations of the   operation of the loudspeakers (HP) of said installation.   4. Method according to any one of claims 1 to 3, using a   converter receiving device or decoder receiver (24) for receiving and transforming the signals emitted by the loudspeakers (HP), this device (24) comprising a microphone (12), characterized in that the correct orientation of the latter in direction of the loudspeakers (HP) to be checked, is obtained by means of a laser diode pointer (10) disposed near this microphone (12) and emitting a laser beam in a direction identical to that of the field for picking up said microphone (12).   5. Method according to any one of claims 1 to 3, characterized in that   that the serial signals inaudible to the human ear are modulated and sent to the input of the amplifier (21) or of each amplifier (21) on two frequencies of 18.5 kHz and 19.5 kHz, respectively, or on two   frequencies of 15 kHz and 15.5 kHz, respectively.   6. Control device for the loudspeakers of a sound installation of the kind comprising a source of emission of acoustic signals (22) connected   at least one amplifier (21) itself connected to a plurality of loudspeakers   loudspeakers (HP), characterized in that it comprises, on the one hand, at least one transmitting device (23) comprising an FSK transmitter (03) capable of generating and transmitting serial signals modulated at frequencies inaudible for I ' man, said amplifier (21) and, on the other hand, a portable converter receiver (24) comprising a microphone (12) making it possible to pick up the inaudible serial signals emitted by each speaker (HP) of a set of loudspeakers speakers (20), and connected to an FSK receiver (15) making it possible to transform the inaudible serial signals picked up into parallel signals, this FSK receiver (15) supplying a signaling means perceptible by -15- 2789540   the operator, this signaling means being able to be visual such as a display   digital (17) and / or audible such as an acoustic vibrator or buzzer (19).   7. Device according to claim 6, applicable to sound installations comprising several amplifiers (21) each of which is connected to a plurality of loudspeakers (HP), characterized in that a transmitting device (23) is connected to each amplifier (21), this transmitting apparatus (23) comprising a code encoder (02) capable of generating binary coded serial signals (TTL) as a function of the decimal value indicated on a coding wheel (05), and in that the converter reception apparatus (24) comprises a code decoder (16) whose input is connected to the FSK receiver (15) and whose output is   connected to the digital display (17).   8. Device according to one of claims 6 or 7, characterized in that   the transmitting device or encoding transmitting device (23) comprises a switcher (01) whose input is connected, on the one hand, to the source of emission of acoustic signals (22) of the installation making it possible to broadcast signals general call, and secondly, to the FSK transmitter (03), and whose output is connected to the amplifier (21) connected to said transmitter device (23), this switch (01) being configured to address in priority the general call signals audit amplifier (21).   9. Device according to claim 6, characterized in that the converter receiving device (24) comprises a laser diode pointer (10) disposed near the microphone (12) so as to emit a laser beam in a   direction identical to that of the pick-up field of said microphone (12).   10. Device according to one of claims 6 or 7, characterized in that   the FSK transmitter (03) is configured to transmit serial signals on -16- 2789540   frequencies of 18.5 kHz and 19.5 kHz or on frequencies of 15 kHz and 15.5 kHz.   11. Device according to claim 7, characterized in that the transmitter-encoder device (23) comprises a microprocessor card (06) and the output of which is connected to an information processing means such as, for example, a LCD display system (07);   12. Device according to one of claims 6 or 7, characterized in that a   electronic timing circuit or assembly (04) for adjusting the   time between two pulses, is connected to the code encoder (02).   13. Device according to one of claims 6 or 7, characterized in that a   amplifier (13) is connected between the microphone (12) and the FSK receiver (15) of the converter receiver or decoder receiver (24), this amplifier (13) making it possible to increase the amplitude of the serial signals picked up by said microphone (12).   14. Device according to claims 13, characterized in that a pass filter   strip (14) is connected between the amplifier (13) and the FSK receiver (15).   15. Device according to one of claims 13 or 14, characterized in that a   frequency detector (18) is connected, on the one hand, to the acoustic vibrator or buzzer (19) and, on the other hand, to the amplifier (13) or to the bandpass filter (14).