The patent's assignee for patent number 8634945 is
News editors obtained the following quote from the background information supplied by the inventors: "An audio generation device allows restoral of the analogue audio signal of a digital sound sequence. It uses a bank of digital samples of sounds, and an audio conversion chain, capable of delivering, to a loudspeaker, an analogue audio signal corresponding to a determined sequence of digital samples of the bank, which corresponds to a voice or sound message to be emitted.
"Such a device is schematically represented in FIG. 1. It comprises a control circuit 1, which receives the requests to emit sound messages, a data bank 2 containing digital samples Dj and a digital analogue conversion audio chain which delivers an analogue audio signal Si to a loudspeaker 3.
"On receipt of a control signal CG(
"The audio chain 10 provides as output an analogue signal Si, to the loudspeaker 3 which delivers the requested message.
"The bank of samples can comprise samples of sound sequences constructed digitally, corresponding for example to sound beeps (mono or multi-frequency digital generators), or obtained by digital sampling at an appropriate frequency, of a recorded audio analogue signal. Typically, a sampling at a frequency of the order of 16 kilohertz and an amplitude coding on 16 bits are suitable for the envisaged application.
"The digital analogue conversion chain typically comprises a digital analogue converter 11 and an analogue adaptor 12, typically an audio amplifying filter. By nature, the sound messages restored have variable characteristics (frequencies, amplitudes, durations).
"In practice the digital circuitry (circuits 1, 2, 11) operates at the same tempo as a clock signal CK. The frequency of this clock signal corresponds in practice to the sampling frequency of the samples Dj, i.e. typically 16 KHz, in the case of the above example for instance.
"In an aircraft, the use of an audio generation device (or of several) by the alarm management system in order to make voice announcements to the pilot, for example a fault detection announcement, or aircraft altitude announcements in the descent phases, is advantageous in that it allows the pilot to concentrate on pure piloting, and that he is capable of reacting immediately and directly, to the announcement of such or such a message, by corresponding piloting actions.
"Such a use relating to the management of alarms nevertheless assumes that the integrity of these audio generation devices can be guaranteed. It must be possible to guarantee this integrity at any moment. It must notably be possible to continuously verify proper operation of the function for applying a sequence of samples as input to the digital analogue converter, on activation of a corresponding control signal by the system for generating the alarms and the proper operation of the whole of the conversion chain, namely the digital analogue converter and the amplifier.
"More particularly, the usual faults to be detected are an erroneous working frequency, for supplying the converter with samples, or the decoding operation in the converter, which would be manifested through an error in the spectrum of frequencies of the analogue signal restored at output, or errors of amplitude decoding in the converter or errors of analogue adaptation in the amplifier, which would be manifested through an error in the amplitude of the analogue signal restored at output.
"Depending on the degree of reliability sought, other errors have to be detected, such as the unexpected emission of sound announcements, that is to say outside of any instruction from the system for generating alarms, corresponding for example to the noise generated by a defective amplifier, or the non-emission of a sound announcement, although it has been instructed.
"However, sound messages being diverse, the characteristics of the analogue signal delivered at the output of the conversion chain are variable, unpredictable, both as regards amplitudes, and frequencies, or durations.
"Hence, the design of an integrity monitoring system for such a device, which would be based on an analysis of the analogue signal at output, is not easy."
As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "The subject of the invention is a device for generating sound messages with integrated detection of defects, which makes it possible to respond to this requirement in a reliable, simple and inexpensive manner.
"The defects detection principle on which the invention is based consists in the digital superposition, on the input of the digital analogue converter receiving the samples of the audio sequences to be restored, of a digital test signal having a spectrum of frequency(frequencies) outside of the spectrum of frequencies of the audio sequences of the data bank, and in an extraction of a corresponding test signal, at the output of the conversion chain, the characteristics of which are compared with those of the test signal applied as input. This detection principle has notably the advantage of being simple to implement in an integrated manner, in an audio generation device.
"The invention therefore relates to a device for generating sound messages, comprising a first digital analogue conversion audio chain for providing an audio signal to a loudspeaker, the said chain being activated by a monitoring circuit on receipt of a control signal for instructing emission of a sound message, so as to convert a sequence of digital samples corresponding to the said sound message. It comprises an integrated device for detecting faults comprising means for superimposing, at the input of the said audio chain, a test signal whose spectrum of frequency(frequencies) is chosen outside of the spectrum of frequencies of the sound messages to be emitted, the said test signal being furthermore applied as input to a second audio chain identical to the first audio chain, means for adding together the respective outputs of the two audio chains, and extracting an output test signal, and means for comparing the characteristics of the said test signal applied as input and of the said output test signal.
"Notably, the detection of operating defects of the device is carried out by comparing the characteristics of the test signal extracted at output, with those of the test signal applied as input. It makes it possible notably to detect errors of frequency and errors of amplitude conversion or adaptation in the conversion chain.
"Preferably, the circuit for detecting defects is able to perform a correlation of the test signal extracted with a signal representative of the audio emission phases requested. In this way, the device is capable of detecting an unexpected emission of an audio sequence, that is to say outside of any instruction from the system for generating alarms, or else the non-emission of a sound sequence which has been instructed.
"According to another aspect of the invention, the analogue signal corresponding to the sound message requested, without the test component, is easily recovered at output by applying the test signal as a common mode signal of an output transformer. The loudspeaker is then typically connected between the two ends of the secondary winding of the output transformer.
"The invention applies notably to a system for managing alarms, in particular systems aboard aircraft, for vocally announcing alarms and/or information.
"The invention also relates to a method for detecting defects in an audio generation device.
"Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious aspects, all without departing from the invention.
"Accordingly, the drawings and description thereof are to be regarded as illustrative in nature, and not as restrictive."
For additional information on this patent, see: Phelippeau, Jacques; Ratinaud,
Keywords for this news article include: Thales, Information Technology, Information and Data Aggregation.
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