DE102008018615B3 - Apparatus and method for generating a monitor sound - Google Patents

Abstract

The invention relates to a device and a method for generating a Mithörtons (84), in particular for use in aerospace engineering. The device comprises a headset (50) with microphone and earphones, for detecting a source signal (80) and for playing a Mithörtons (84), a communication system (43, 40) for connection and control of the headset (50) and a Transceiver module (20). The device for generating the monitoring sound (84) is characterized in that it also comprises a comparison device (60) which transmits both the signal (81) received in the transmission / reception module (20) and that actually transmitted by the transmission / Receive module (20) receives transmitted signal (82), and determines that the originating signal (80) is sent. In this case, the comparator (60) instructs the communication equipment (43, 40) to output the originating signal (80) as a sidetone (84) via the earphone of the headset (50).

Description

The The invention relates to an apparatus and a method for generating a monitor, in particular for use in aerospace engineering.

In Aircraft, such. As helicopters or aircraft, it is common that a to be transmitted Voice signal is fed back to a server in his headset. this has ergonomic reasons because of the high noise level the operator can often do not hear his spoken words, which generally leads to speech uncertainties. The other is with it but also safety-related aspects, because this procedure is used especially in aviation to the crew to indicate that the voice signal to be transmitted actually transmitted becomes. This type of feedback is usually also for the aeronautical license required. It is realized by in the final stage of the transmitter, the signal to be transmitted demodulates and to the earpiece of the speechware is reflected. This reflected signal is generally sidetone called.

US5396651 A describes a radio communication system for transmitting a radio signal between a transmitter and a plurality of receivers. It shows in 2 a communication system with push-to-talk application and the optional generation of a monitoring sound.

In WO97 / 09798 A1 Also shown is a device for generating a Mito sound.

In US 4903298 A A device for communication in an encryption operation in aircraft is shown.

By the fact that the signal to be sent only at the output stage of the Transmitter of the transmit / receive module is tapped and reflected, can ensuring that a sidetone is only generated if the signal is actually sent. This will make the crew immediately over possible Transmission problems informed.

on the other hand leads this late reflection but also to delays between the recording of the speech signal and the reflected sidetone, which are for the crew, in particular the speaker, prove disturbing, as they are perceived as an unpleasant "echo" and strongly inhibit the language flow. Investigations in a language laboratory have revealed that delays of the listening tone from greater than or equal to 38 ms as disturbing be felt.

This Problem is further compounded when the recorded speech signal is encrypted prior to transmission for security reasons. In such cases, you add before the send / receive module an encryption module, also called a key device, which encodes the speech signal and due to the applied mathematical algorithms the signal flow delayed further. Such delays can in special cases to about 85 ms in one signal direction. Since the sidetone only is reflected at the power amplifier of the transmitter, this passes through the encryption module twice, once on the way from the headset to the transmitter and again on the way back from the transmitter to the headphones. The resulting delays of additional about 170 ms between spoken signal and sidetone are not justifiable.

Also in unencrypted Operation must be with delays in the order of magnitude stated above because of security reasons - especially in military Applications - undesirable, the encryption module to bridge, there such bridging paths the general privacy of the system.

In The present invention is an apparatus and a method which make it possible a monitoring signal to generate which over a very short delay time compared to the original Signal has. There will be delays in the order of magnitude of less than 10 ms. Furthermore will ensure that - like in the systems of the prior art - a sidetone is only generated if the signal to be sent is actually transmitted by the transmitter becomes. After all will also be aspects of privacy considered, by excluding the feedback sidetone between Transmitter and headphones decoupled and intercepted can be.

According to one aspect of the invention there is disclosed an apparatus for generating a co-hitting sound in aircraft comprising a headset with microphone and earphone for recording a signal which is called an origin signal in sequence. In addition, the device comprises an interface module, also called control unit, for connection and control of the headset and a send / receive module, also called radio or radio, for sending the original signal. In addition to a headset and other input / output devices are conceivable, such. B. a speaker over the other cabin members can follow the conversation of the pilot NEN. The interface module is usually part of an internal communication system, also called interface control device, within the aircraft, to which also the transmit / receive modules can be connected. The interface module is considered below as a functional part of the communication system. On the other hand, the transmit / receive modules are considered as functionally separate units of the communication system, even if they can be technically implemented as plug-in modules of the communication system. The communication system can be an analog or digital system. IP-based communication systems are also conceivable. Depending on the application, a variety of transmit / receive modules can be used, including HF (High Frequency) and / or V / UHF (High / Ultra High Frequency) ranges. The signal flow in the transmission mode is such that on the basis of the microphone of a headset a source signal, for. As a voice signal is recorded, which is forwarded via the interface module and the communication system to a transmit / receive module. The signal is modulated and sent in the send / receive module. In receive mode, a signal is received via the transmit / receive module, demodulated and then passed through the communication system and the interface module to the headset, where it is output via the headphone / earphone / speaker.

The Device for generating the Mithörtons is characterized that they also have one Comparing means, which both in the send / receive module incoming signal, called in sequence input signal, as well as actually from signal transmitted to the transmit / receive module, modulated in sequence Called transmit signal, receives, and finds that over the microphone of the at least one headset recorded signal is sent. In this case, the comparison device has the Communication system on, the original signal as a sidetone over the earphones the headset. Alternatively, the comparator could also directly the interface module integrated into the communication system to which the headset is connected instruct the originating signal as a sidetone over the earphones the headset. The following is the general Case considers that the sidetone generated by the communication system, which is the special Case that the sidetone directly from an interface module, ie a functional part the communication system is generated.

in the Transmission mode is that in the send / receive module incoming signal, d. H. the input signal, in general order the detected source signal and actually from the transceiver module transmitted signal, d. H. the modulated transmit signal to a modulated version of the recorded original signal. to Processing within the comparator needs to be modulated Version of the original signal at the input of the comparator be demodulated. Alternatively could also the send / receive module for the demodulation of the actual of the signal transmitted to the send / receive module. As a result, this modulation aspect is not considered further and it becomes exclusive referred to the (demodulated) transmit signal.

By The apparatus described above, it is possible that problem of high delay times between Source signal and sidetone to eliminate, as the sidetone generated directly in the communication system from the original signal becomes. At the same time by the use of the comparison device guaranteed that the sidetone is generated only if the original signal is actually from the Transmit / receive module is sent.

According to one Further aspect of the invention comprises the comparison device a variety of signal processing components for processing the input and transmit signal. Through a filter stage can a relevant frequency range are isolated. Is it correct? the original signal is voice signals, so is usually the voice frequency range of 300 Hz to 3.4 kHz of interest. By using filters, such as B. Besselfiltern can Signal components outside this frequency range are cut out. Based on an amplifier stage can the signal levels of the input and transmit signal are adjusted. This is in particular in a preferred embodiment with analog signals of importance, which in a following comparator stage, z. B. an analog / digital converter, to be digitized. If it is If the signals are already digital signals, then in particular the comparator stage are omitted.

According to another aspect of the invention, the comparison means comprises a correlator which determines the correlation between the input signal and the transmission signal. In this case, both signals may have previously gone through the signal processing components described above. One way to determine the correlation between the two signals is to subtract both signals from each other and the difference signal itself or characteristics of the difference signal, such. For example, use his energy as a measure of correlation. The difference signal can be determined either in blocks, ie for signal sequences of a specific length, or also continuously. For example For example, one could occupy two memory locations with blocks of samples of the input signal and of the transmission signal and then compare these, sample by sample. The measure of the difference of the two memory locations would then represent a degree of correlation. This process could then be performed sequentially for subsequent blocks of samples of the input signal and the transmit signal.

there it is important that possible time delays, which is the send signal to the Receive signal due to passing through the send / receive module has taken into account become. This can be done by the through the send / receive module caused time delay determined beforehand and then in the determination of the correlation, through appropriate delay of the reception signal is taken into account. Typical delay times of transmit / receive modules are approx. 5 ms. In a further embodiment could the delay time while an initialization process or continuously automatically be determined by the correlator. By way of example, the correlator could be the input signal and the send signal via a range of a few milliseconds, e.g. B. 10 ms, ge against each other shift and the delay time Determine the maximum correlation between the two signals supplies.

Other methods for determining the correlation between the input signal and the transmission signal are conceivable, in particular with regard to the robustness with respect to the detection that an original signal is actually transmitted. Thus, distortions of the transmit signal from the input signal could lead to challenges in correlation determination. Since such distortions have little effect on the signal envelope, it could, as in 1 represented, be beneficial, the envelope 10 the input and transmit signal 11 to determine and correlate these two signals, z. B. according to the methods described above to determine. Alternatively, one could also model the input signal and the transmit signal, e.g. Example, based on a predictive language model or a model based on frequency analysis, and then determine the correlation of the signals on the correlation of the respective model parameters.

To Determining the correlation between the input signal and the Send signal can over a predetermined or dynamic or adaptive threshold be determined whether input signal and transmit signal sufficient similarity and thus ensures that the original signal is sent. If so, the comparator according to the invention the instruction to the communication system, the origin signal to the earphone of the Headset as a sidetone issue. This instruction can be via a binary control signal between comparator and communication system done which z. B. assumes the logical value "0", if the Input signal and the transmit signal match, i. H. if that Origin signal actually is sent, and assumes the logical value "1" if both signals do not match.

According to one In another aspect of the invention, the device comprises various Activities, about the reliability and the privacy of the device to ensure. To ensure that in case of failure of the comparator still a sidetone is generated, the device can be operated such that in principle a sidetone by returning the transmit signal is generated. Only with a control signal with a logic value "0" the sidetone becomes direct from the communication system on the earphone of the headset. In the case of a control signal with a logic value "1", the monitoring sound is fed back via the Transmission / reception module. When looking at the control signal at the comparator by a PULL UP resistor at rest to a logical Value "1" forces you to set sure that the sidetone exclusively is generated during transmission mode and by the send / receive module, in case of malfunction of the comparator, or of the communication system, with correct operation of the comparator.

These Approach over it Be sure that even in the initialization phase when the Comparator due to the signal transit times and due of possible transients still no match of the transmit signal and the input signal, yet a sidetone is generated.

The privacy the device can thereby increased be that one the comparator including feedback galvanically separated from the other linguistic circuits to overcoupling to prevent other language groups. This is especially true required if classified as secret in the other linguistic circles Transmit signals become.

According to a further aspect of the invention, the device further comprises between the communication system and the transceiver module an encryption module for encrypting the signals exchanged via the headset. It is quite possible that the encryption module, as well as the Send / Emp fangs module, part of the communication system is and z. B. is realized as plug-in module. In the following, however, the encryption module, as well as the transmission / reception module, independent of the technical realization considered as a separate communication unit functional unit. The encryption ensures that a clear signal is converted into an incomprehensible, tap-proof signal with the help of an encryption method, a so-called cryptosystem. The key parameter of encryption is one or more keys. There is a distinction between symmetric and asymmetric encryption methods, such. B. the Diffie-Hellmann or the RSA method.

Next Encryption modules can between Communication system and transmit / receive module also other modules, as u. a. Analog / digital converters, VoIP gateways, etc., be switched which also the delay time can affect negatively.

According to one Further aspect of the invention are the comparison device additional information about the Operating state of the device provided. Amongst other things could the communication system or the interface module, the comparison device via a binary interface about that inform you that the headset is currently in broadcast mode, d. H. that a source signal is detected and to the transmit / receive module is sent. This is particularly advantageous in push-to-talk (PTT) systems in which the speaker presses a button to which often operated in half-duplex mode is claimed, and thus ensures that its voice signal sent becomes. The pressing The PTT button can be used as a sign for the transmission mode over a binary one Interface are communicated to the comparison device. The comparator can use this information and, in particular if the comparison device comprises a correlator, the determination of the correlation between the input signal and the transmission signal to the transmission mode restrict. A necessary condition for the presence of a positive correlation and thus for one logical value "0" of the control signal to the communication system, could be that before the communication system or the interface module the comparator signals the transmission mode.

Besides, one could Encryption module the comparator above inform if it is in encryption mode or in clear mode, d. H. in unencrypted Mode, works. As already explained above, encryption modules are used also in the clear mode at considerable delay times, since a bridging of the Encryption module for wiretapping security reasons often not permissible is. Consequently, could the function of the comparator is limited to the clear mode, so that, in the presence of a correlator, a necessary condition for the presence a positive correlation, i. H. for a logical value "0" of the control signal to the communication system, which could be clear mode. In another embodiment could the information about the encryption mode an influence on the used method for correlation determination to have.

According to one Further aspect of the invention, the comparison device and in particular the correlator as a separate hardware and software component be implemented. A microprocessor can calculate the Calculate correlation between the input signal and the transmit signal. About that can out the signals to be compared are written in memory components and cached. Alternatively, the comparator could integrated as an additional module in already existing components become. As the comparison device in particular in use of encryption modules, due the additional Delay, could be beneficial it makes sense to use the comparison device within the encryption module to realize. This can be particularly beneficial to the investigation the correlation of encrypted Input and transmit signals to facilitate.

in the Furthermore, the invention will be described with reference to an embodiment. It shows

1 an already mentioned representation of a possible source, input, transmit signal with envelopes;

2 a block diagram of a communication device with generation of a Mithörtons from the prior art;

3 a block diagram of a communication device with comparator; and

4 a section of the block diagram 3 ,

2 shows a block diagram of a communication device with generation of a Mithörtons from the prior art. The headsets 50 - 54 have microphones and earphones. The headsets 50 - 54 are via interface modules 41 - 43 to the communication system 40 connected. As already noted above, the interface modules 41 - 43 as a functional part of the communication system 40 considered. On the transmission side are transmitting / receiving modules 20 - 24 , optional via encryption modules 30 - 32 , to the communication system 40 connected. As noted earlier, the transmit / receive modules 20 - 24 and the encryption modules 30 - 32 technically as plug-in modules of the communication system 40 However, they are here as functional of the communication system 40 considered separate units.

As described above, an originating signal from the microphone of a headset 50 recorded and passes on the way to the send / receive module 20 the interface module 43 , the communication system 40 and the encryption module 32 , In the send / receive module 20 During transmission, the sidetone is generated, which then goes in the reverse direction to the earphone of the headset 50 is transported. When passing through this route, there are delay times between the sidetone and the original signal of about 170 ms, which are for the user of the headset 50 annoying and generally slow down the flow of speech.

3 shows a communication device with the comparison devices according to the invention 60 - 62 ,

4 shows a section 3 with a headset 50 , an interface module 43 , a communication system 40 , an encryption module 32 , a send / receive module 20 and a comparator 60 ,

One from the microphone of the headset 50 recorded origin signal 80 goes through the interface module 43 and the communication system 40 , In the encryption module 32 the source signal is optionally encrypted. The control signal 91 indicates if the encryption module is 32 in clear mode or in encryption mode. The origin signal 80 will after passing through the encryption module 32 to the input signal 81 , which then to the send / receive module 20 is forwarded. In the send / receive module 20 becomes the input signal 81 modulated and over the antenna 70 transfer. In addition, this modulated signal is reflected, then demodulated and transmitted signal 82 at an interface of the transmit / receive signal 20 output. After passing through the encryption module 32 in which the transmission signal 82 is optionally decrypted, so creates the sidetone 83 , which then via the communication system 40 and the interface module 43 as a sidetone 84 on the earphone of the headset 50 is issued.

Depending on whether it is the communication system 40 is an analogue or digital system, these are the signals 80 . 81 . 82 . 83 . 84 to analog or digital signals.

4 also shows an embodiment of the comparison device 60 , which in the present example exclusively from a correlator 60 consists of the input signal 81 and the transmit signal 82 , as well as the control signal 90 , which indicates the transmission mode, and the control signal 91 which indicates the encryption mode is recording. This can be the input signal 81 and the transmit signal 82 a number of signal processing components, such as. B. go through a filter stage, an amplifier stage and a comparator stage.

On the basis of the above-described method, it is determined on the basis of these four signals whether the original signal 80 actually from the send / receive module 20 is sent. In one embodiment, this is done by checking to see if the headset 50 is in transmission mode, ie whether the control signal 90 has a certain predefined binary value, and whether the encryption module 32 in clear mode, ie whether the control signal 91 has a certain predefined binary value. Only if both conditions are true, in the present example, is the correlation between the input signal 81 and the transmit signal 82 certainly. The correlation is z. B. determined by gradually adding certain blocks of samples of the input signal 81 and the send signal 82 be deducted from each other and it is checked whether the energy of the difference signal does not exceed a predefined threshold. In this case, that of the send / receive module 20 caused delay time between the input signal 81 and the transmit signal 82 compensated in advance. Of course, others, such. For example, the methods described above for determining the correlation may be used.

If a correlation between the two signals is detected in the above case, then the control signal becomes 92 forced to the logical value "0" and to the communication system 40 or directly to the interface module 43 (this case is not shown) forwarded. By this control signal 92 then becomes the communication system 40 or the interface module 43 , as a functional part of the communication system 40 , instructed, the origin signal 80 directly in the communication system 40 as a sidetone 84 on the earphone of the headset 50 to reflect. In this case, that of the send / receive module 20 generated sidetone 83 not considered.

In the event that, for. B. by a radio tion of the comparator / correlator 60 , no correlation between the input signal 81 and the transmit signal 82 was detected, although the control signal 90 indicates that the headset 50 is in transmission mode, so the control signal keeps 92 the logical value "1", which is given for example by a PULL UP resistor 40 that of the send / receive module 20 generated sidetone 83 as a sidetone 84 to the earphone of the headset 50 hand off.

In The present invention has been directed to an apparatus and method for generating a monitor sound disclosed in aircraft, which allow disturbing delays between a source signal, in particular a speech signal, and to avoid the associated sidetone. Also at Use of encryption modules and other intermediate modules, it is thus possible to have delay times significantly below the audible Threshold of about 38 ms to realize and continue to ensure that a sidetone only is generated upon successful transmission. This is done by the introduction a comparison device according to the invention allows which determines if the source signal indeed is sent by the send / receive module and in this case the communication system instructs the sidetone directly from the source signal.

10

Enveloping one embodiment an origin, input, transmit signal

11

embodiment an origin, input, transmit signal

20 21, 22, 23, 24

Transmit / receive modules

30 31, 32

Encryption modules

40

communications system

41 42, 43

Interface Module

50, 51, 52, 53, 54

Headsets

60 61, 62

comparators

70

antenna

80

Original signal

81

Input signal

82

Transmission signal

83

Sidetone (between Send / receive module and communication system)

84

Sidetone (between Communication system and headset)

90

control signal (Transmission mode)

91

control signal (Encryption Mode)

92

control signal (successful transmission / correlation)

Claims (11)

Device for generating a monitoring sound ( 84 ) in aircraft, comprising: - a headset ( 50 ) with microphone and earphones; - a communication system ( 43 . 40 ) for connecting and controlling the headset ( 50 ); and a send / receive module ( 20 ); characterized in that the device also comprises a comparison device ( 60 ), which - that in the send / receive module ( 20 ) incoming voice signal ( 81 ) receives; Actually from the send / receive module ( 20 ) to be sent voice signal ( 82 ) receives; By comparing the received speech signals, it is found that a sound is transmitted through the microphone of the at least one headset ( 50 ) detected origin signal ( 80 ) is sent; and - in this case the communication system ( 43 . 40 ), the original signal ( 80 ) as a sidetone ( 84 ) via the earphone of the headset ( 50 ). Device according to claim 1, which further between communication system ( 43 . 40 ) and transmit / receive module ( 20 ) an encryption module ( 32 ) for encryption of the original signal ( 80 ). Device according to claim 1 or 2, wherein the comparison device ( 60 ) - Status information of the device, such as transmission mode ( 90 ) and / or encrypted / unencrypted operation ( 91 ) receives; and - additionally uses this information to determine that the source signal ( 80 ) is sent. Device according to one of claims 1 to 3, wherein the communication system ( 43 . 40 ) is designed such that - if it is determined that the original signal ( 80 ) is not sent, or - if a malfunction of the comparator ( 60 ), the sidetone ( 84 ) via a return channel from the transmit / receive module ( 20 ) via the communication system ( 43 . 40 ) to the earphone of the headset ( 50 ). Device according to one of claims 1 to 4, wherein the feedback ( 92 ) between comparator ( 60 ) and communication system ( 43 . 40 ) over which the comparator ( 60 ) the communication system ( 43 . 40 ), the sidetone ( 84 ), is galvanically isolated. Device according to any preceding claim, wherein in the comparison device ( 60 ) the frequency band of the in the send / receive module ( 20 ) incoming speech signal ( 81 ) and of the send / receive module ( 20 ) speech signal to be sent ( 82 ) are limited by a filter stage. Device according to any preceding claim, wherein in the comparison device ( 60 ) into the send / receive module ( 20 ) incoming voice signal ( 81 ) and that of the send / receive module ( 20 ) speech signal to be sent ( 82 ) are normalized by an amplifier stage. Device according to any preceding claim, wherein in the comparison device ( 60 ) into the send / receive module ( 20 ) incoming voice signal ( 81 ) and that of the send / receive module ( 20 ) speech signal to be sent ( 82 ) are sampled by a comparator stage. Device according to any preceding claim, wherein the comparison means ( 60 ) a correlator ( 60 ) incorporated into the send / receive module ( 20 ) incoming voice signal ( 81 ) and that of the send / receive module ( 20 ) speech signal to be sent ( 82 ), the difference between the two signals representing a measure of the degree of correlation between the two speech signals. Device according to claim 9, wherein the time delay between the transmission in the send / receive module ( 20 ) incoming speech signal ( 81 ) and from the send / receive module ( 20 ) speech signal to be sent ( 82 ), which from the send / receive module ( 20 ) is taken into account in the determination of the degree of correlation. Method for generating a monitor sound ( 84 ) in aircraft, comprising the steps of: - tapping into a transceiver module ( 20 ) incoming speech signal ( 81 ); - picking up the from the send / receive module ( 20 ) speech signal to be sent ( 82 ); Determining by comparing the picked-up speech signals that an originating signal recorded via a microphone ( 80 ) from the send / receive module ( 20 ) is sent; and - in this case instructing a communication system ( 43 . 40 ), which serves to connect and control the microphone and an earphone, the original signal ( 80 ) as a sidetone ( 84 ) on the earphone.