EP0748494B1 - Detecteur de sirene - Google Patents

Detecteur de sirene Download PDF

Info

Publication number
EP0748494B1
EP0748494B1 EP94908234A EP94908234A EP0748494B1 EP 0748494 B1 EP0748494 B1 EP 0748494B1 EP 94908234 A EP94908234 A EP 94908234A EP 94908234 A EP94908234 A EP 94908234A EP 0748494 B1 EP0748494 B1 EP 0748494B1
Authority
EP
European Patent Office
Prior art keywords
siren
detector
sound
signal
frequency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP94908234A
Other languages
German (de)
English (en)
Other versions
EP0748494A1 (fr
Inventor
Peter Robert Henderson Mcconnell
Patricia Kavanaugh
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sonic Systems Corp
Original Assignee
Sonic Systems Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sonic Systems Corp filed Critical Sonic Systems Corp
Priority to AT94908234T priority Critical patent/ATE167584T1/de
Publication of EP0748494A1 publication Critical patent/EP0748494A1/fr
Application granted granted Critical
Publication of EP0748494B1 publication Critical patent/EP0748494B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/07—Controlling traffic signals
    • G08G1/087—Override of traffic control, e.g. by signal transmitted by an emergency vehicle

Definitions

  • This application pertains to an improved siren detector for detecting siren sounds which precess with known characteristics within a selected frequency band.
  • the siren detector facilitates preemptive control of traffic lights to enable a vehicle equipped with the appropriate siren to pass through an appropriately equipped intersection on a priority basis.
  • the prior art has evolved various ways of controlling or "pre-empting" vehicle traffic lights to stop traffic at an intersection so that an emergency vehicle may pass unimpeded through the intersection on a priority basis.
  • One technique involves the placement of a special transmitter on each emergency vehicle which is to be allowed priority passage through intersections.
  • the traffic light controllers at each preemptable intersection are equipped with a receiver which receives signals transmitted by the transmitter and there upon actuates the traffic lights to stop the normal flow of traffic.
  • this technique is relatively expensive and is cumbersome in that the personnel in the emergency vehicle must manually actuate the transmitter in order to control the traffic light.
  • Traffic light controllers at preemptable intersections have also been equipped with detectors capable of detecting flashing lights (normally special strobe lights) mounted on each emergency vehicle which is to be allowed priority passage through the preemptable intersections.
  • this is similar to the system mentioned in the preceding paragraph, in that the emergency vehicle light replaces the special transmitter.
  • the system does however enjoy something of a cost and utility advantage over the system mentioned in the previous paragraph, since emergency vehicles are normally equipped with flashing lights which are actuated in emergency situations.
  • the cost advantage diminishes if special lights must be provided in order to actuate the detector circuitry which interfaces with the traffic signal controller.
  • the prior art has evolved a number of circuits for detecting siren sounds (see for example published European Patent Application No. 318,668 and United States Patent No. 4,956,866).
  • the inventors consider these to be problematic in that they are susceptible to false alarm triggering by sounds emanating from sources other than emergency vehicle sirens. They also provide unreliable detection of siren signals that have a relatively long period as well as very long detection times.
  • the present invention provides an improved siren detector for reliably detecting siren sounds within a selected frequency band and having superior immunity to false alarm triggering by sounds emanating from sources other than emergency vehicle sirens, and having superior ability to detect siren sounds in the presence of high ambient noise levels, and detecting siren signals which have a relatively long period in a short period of time.
  • the invention is based on the observation that the majority of siren sounds are characteristic of a frequency modulated (or FM) waveform in which the frequency is modulated with a very characteristic and periodic waveform.
  • FM frequency modulated
  • the ability of the FM detection scheme yields a great increase in the ability of this invention to detect sirens in very high noise levels.
  • DSP Digital Signal Processing
  • the invention provides a siren detector for detecting siren sounds which precess at known rates within a selected frequency band to facilitate preemptable control of traffic light signals to enable an emergency vehicle to pass through a traffic intersection on a priority basis.
  • a transducer detects the siren sounds and produces a corresponding electrical sound output signal.
  • the sound output signal is then filtered to produce an antialiased output signal which prevents aliasing in a subsequent analog to digital conversion process.
  • the antialiased output signal is then bandpass filtered to reject signals outside the selected frequency band.
  • a limiter-discriminator then performs a constant amplitude scaling of the amplitude components of the filtered antialiased output signal to produce an output signal having frequency and amplitude-scaled components and subsequently removes the amplitude-scaled component, leaving only the desired frequency component.
  • a click filter removes impulsive noise components from the frequency component output by the limiter-discriminator, to produce a filtered discriminator output signal.
  • a sound level detector responsive to the bandpass filtered signal produces a sound level signal indicating that a sound level within the selected frequency band at the input transducer exceeds a selected sound intensity level.
  • a squelch detector is provided to indicate whether a signal to noise level within the selected frequency band at the input transducer exceeds a selected signal to noise level.
  • a detector responsive to the frequency component output by the limiter-discriminator measures the siren sound's period and indicates whether the period is within a selectable range. Another detector responds to the frequency component output by the limiter-discriminator by measuring the siren sound's frequency and indicating whether the measured frequency is within a selectable range. A means is also provided for measuring the siren sound's rate of change of frequency and for indicating whether the measured rate of change of frequency is within a selectable range.
  • a means is also provided to determine a correlation coefficient providing a measure of correlation between the precession rate of the siren sound and a straight line, and for indicating whether the correlation coefficient exceeds a selectable value.
  • a preempt control means produces a preempt output signal for preempting control of the traffic light signals when the siren sound increases in level above a selectable threshold and for deactivating the preempt output signal when the siren sound decreases in level below a selectable threshold.
  • the preempt output signal is held in an enabled state for a selectable period of time.
  • the invention may be implemented as a programmable signal processor operated according to a computer program.
  • the programmable signal processor may have a communications port allowing the computer program or user selectable operating parameters to be externally loaded from an external source, which may be remotely located.
  • Figure 1 is a block diagram illustrating the basic operation of the siren detector according to the invention.
  • Figure 2a and 2b are diagram illustrating the basic configuration of a four channel siren detector at a street intersection, and the configuration of a plurality of siren detectors.
  • Figure 3 is a block diagram illustrating the limiter discriminator of the siren detector according to the invention.
  • Figure 4a, 4b, and 4c are diagrams illustrating the ideal characteristic signals of three of the many common types of siren sound which are detected when processed in accordance with the preferred embodiment of the invention.
  • Figures 5, 6, and 7 are diagrams illustrating the typical actual characteristics of three of the many common types of siren sound which are detected when processed in accordance with the preferred embodiment of the invention. These are the yelp, high-low, and wail respectively
  • Figure 8 is a diagram illustrating the effect of the click filter in removing the FM clicks from the received signal when processed in accordance with the preferred embodiment of the invention.
  • Figure 9 is a diagram illustrating the operation of the median filter, used as the click filter.
  • Figure 10 is a detailed diagram of a generalized siren detector used for classifying a sound as being one of a number of desired siren types.
  • Figure 11 is a block diagram of a noise operated squelch detector.
  • Figure 12 is a diagram depicting the means for measurement of the waveform period for yelp and high-low sirens.
  • Figure 13 is a diagram depicting an alternate means for measurement of the high-low siren.
  • Figure 14 is a diagram depicting the means by which a wail siren sound is detected using the linear least squares fit of a short line segment to the sampled siren data.
  • Figure 15 is linear correlation coefficient plot for a linear least squares fit to a wail siren. This is the "linearity coefficient" output of the slope detector.
  • Figure 16 is the signal slope output of the slope detector, which gives the rate of change of frequency of the siren signal, for a wail siren.
  • Figure 17 is a block diagram of the siren detector showing the preferred embodiment.
  • Emergency vehicle sirens commonly emit sounds which precess between two frequencies, the minimum and maximum frequencies, with known repetition rates and characteristics.
  • Three of the more common siren sound are commonly referred to as the yelp, high-low, and wail.
  • the ideal characteristics are shown in Figures 4a, 4b, and 4c respectively.
  • the siren has a constant intensity as the signal precesses according to these siren characteristics, and others.
  • a yelp siren sound typically has a minimum frequency of 400 Hz, a maximum frequency of 1400 Hz, and a repetition rate of about 3 Hz.
  • a high-low siren sound typically has a minimum frequency of 400 Hz, a maximum frequency of 600 Hz, and a repetition rate of about 1 Hz.
  • a Wail siren sound typically has a minimum frequency of 400 Hz, a maximum frequency of 1400 Hz, and a repetition rate of about 0.25 Hz.
  • Other siren sounds exist, and new ones may be defined, which may also be detected by this invention using the method described in this invention.
  • Fig. 1 is a block diagram which illustrates the basic operation of a siren detector constructed in accordance with the invention. A brief overview of the invention will first be provided with reference to Fig. 1. A detailed description of the preferred embodiment will then be provided.
  • the siren detector utilizes an input transducer 1 to detect sound energy and convert those to electrical signals suitable for processing by the siren detector. These electrical signals are amplified to some nominal level for processing.
  • the preamplifier 2 is followed by an anti-aliasing filter 3 prior to the analog to digital convertor 4 which converts these analog electrical signals to a digital form for subsequent processing.
  • An analog to digital convertor with a resolution of 12 to 16 bits and a sampling rate of 8.0 kHz has been found to be suitable for processing the wail, yelp, and high-low sirens described so far.
  • a band pass filter 5 with a passband from about 300 Hz to 1800 Hz has been found to suitable for wail, yelp, and high-low sirens.
  • the sampling rate would have to be increased above 8.0 kHz if sirens with maximum frequencies much higher than those discussed so far are to be sampled without aliasing.
  • the digital bandpass filter 5 is used to remove spectral energy outside of the band found in the wail, yelp, and high-low detectors. A passband of 300 Hz to 1800 Hz has been found to suitable for these sirens.
  • the bandpass filter 5 can be combined with the phase splitter required for the limiter-discriminator 6 described in Fig. 3, thus reducing the overall complexity of these two functions.
  • the limiter-discriminator 6 measures the instantaneous frequency of the received signal and the magnitude of that signal.
  • the limiter-discriminator output signal sampling rate is reduced by the decimator 7 to a much lower sample rate.
  • a decimation of 8.0 kHz to 40 Hz has been found to be suitable. Since the actual spectral content of the sirens variation of frequency with time, as shown in Figs. 5, 6, and 7, is typically less than about 15 Hz, the sample rate after the low pass filter in the decimator need only really be greater than about 30 Hz. This sample rate reduction greatly reduces the processing demands of the subsequent steps.
  • Another key advantage of this low pass filter operation is that it allows the limiter-discriminator detector to be operated essentially as a wideband frequency modulation detector. This allows the great improvement in siren detectability over conventional means. As is the case with conventional FM receivers of the type discussed by Jakes in "Microwave Mobile Communications” (John Wiley & Sons, 1974 ISBN 0-471-43720-4) it can be shown as the ratio of the input signal bandwidth at the input transducer 1 to the baseband output of the-limiter discriminator 6 increases, the baseband output signal to noise ratio increases for the same input signal to noise ratio.
  • the input bandwidth of the detector is defined by the input signal bandpass filter, which is about 1500 Hertz, and the low pass filter following the limiter-discriminator, which is about 15 Hertz.
  • the output of the click filter 8 in Fig. 1 serves as an input to a plurality of detectors.
  • they are yelp detector 9, High-Low detector 10, and wail detector 11.
  • One of more "Other Siren Detectors" 12 may be added to detect additional siren types, or replace any or all of the yelp, high-low, and wail siren detectors. These detectors determine if the variation of the signal frequency with time meets a number of criteria which classify it as one of a number of siren types which the siren detector has been configured to detect.
  • the output(s) of these detectors serve as one of a number of inputs to the Preempt Detection Logic 15.
  • the preempt detection logic uses the outputs from the siren detectors 9, 10, 11, 12, the squelch detector 13, and the sound level detector 14 to determine if the sound detected meets the siren detection criteria. If they do meet the selection criteria, then the PREEMPT signal to the traffic light controller is enabled.
  • the signal at 5 is input to the Sound Level Detector 14 which measures the magnitude of the that signal and compares it against a preset level threshold. If the magnitude of the signal at 5 exceeds the level threshold, it enables the output of the Sound Level Detector. If the magnitude of the signal at 5 does not exceeds the level threshold, it disables the output of the Sound Level Detector.
  • the output of the sound level detector serves as one of the inputs to the Preempt Detection Logic 15.
  • the ambient sound level from sources other than sirens may be so loud that these levels exceed the detection level threshold of the Sound Level Detector 14.
  • the output of the Sound Level Detector 14 would always be enabled and the siren would cause the Preempt Detection Logic 15 to cause a PREEMPT signal sooner than is desired.
  • an additional signal which is a function of the signal to noise ratio is available.
  • the squelch detector is configured such that a threshold signal to noise ratio must be exceeded before the squelch detector output is enabled to indicate this detection criteria has been met.
  • the PREEMPT detection logic 15 uses combinations of the squelch detector 13 output in addition to the siren detector functions, shown in 9, 10, 11, and 12 and the sound level detector 14 of Fig. 1. In normal urban and suburban situations, the PREEMPT detection logic 15 would only enable the PREEMPT output to the traffic light controller when; (a) the sound reaching then input transducer 1 meets one of the valid siren selection criteria of siren detector functions shown in 9, 10, 11, and 12, and (b) the sound reaching then input transducer 1 exceeds the detection threshold criteria of the sound level threshold detector 14.
  • the PREEMPT detection logic 15 would only enable the PREEMPT output to the traffic light controller when; (a) the sound reaching then input transducer 1 meets one of the valid siren selection criteria of siren detector functions shown in 9, 10, 11, and 12, and (b) the sound reaching then input transducer 1 exceeds the detection threshold criteria of the sound level threshold detector 14, and (c) the signal to noise ratio measured at the output of the limiter-discriminator 6 measured by the squelch detector 13 exceeds a squelch detection threshold.
  • Fig 2 (a) shows a typical installation with a traffic light 26, four input transducers 21, 22, 23, and 24 mounted such that they are optimized for detection of sound from one of the four streets which approach the traffic signal 26.
  • the output signals from these transducers go to a four channel siren detector 20 which processes the signals from the input transducers. If an emergency vehicle 25 approaches in the direction of input transducer 24, the channel in the siren detector processing that signal will indicate a PREEMPT signal to the traffic Light Controller 30 for that direction of the traffic light 26 using the traffic light preempt line 31, and/or the pedestrian control preempt line 32.
  • the Traffic Light Controller could then be configured to give the emergency vehicle 25 priority access to the intersection.
  • the siren detector can consist of a plurality of siren detector channels ranging from 1 to many. However, 4 channels is the most common. Single channel detectors could be to control lights at the driveway to fire halls, police compounds, pedestrian controlled lights. etc.
  • Fig. 3 shows one means for realizing a limiter-discriminator.
  • the input signal is split into its real and imaginary components by the phase splitter 40.
  • the complex conjugate and first derivative of the phase splitter output are formed by 41 and 42 respectively.
  • the real part of this product is taken by 44.
  • the power of the input signal is determined by taking the magnitude of the phase splitter output in 46, and then squaring this signal in 47.
  • the frequency of the input signal is then calculated by dividing in block 45 the output of 44 by the output of 47.
  • the output of 47 also serves as the input to the sound level detector 14 in Fig. 1.
  • Fig. 4 (a), (b), and (c) show the ideal frequency versus time characteristics of the three most common sirens, these being the yelp siren, high-low siren, and wail siren respectively. In actual practice, the sirens characteristics are quite different.
  • Fig. 5 shows the frequency versus time characteristic of a yelp siren.
  • Fig. 6 shows the frequency versus time characteristic of a high-low siren.
  • Fig. 7 shows the frequency versus time characteristic of a wail siren. In these three examples, the frequency was measured with actual sirens using the limiter-discriminator shown in Fig. 3.
  • the Median filter is commonly used in image processing to remove impulsive noise. It operates by assembling an odd number of sequential data samples, sorting the samples in ascending or descending order, and then extracting the medial value. It operates in much the same way as sliding window finite impulse response filter, except that it is quite non-linear in nature.
  • the use of the click filter is necessary for the detection of siren sounds where the signal to noise ratio is low.
  • Fig 8 shows the effect of the median filter on an actual wail siren signal having a low signal to noise ratio.
  • the input signal is shown in Fig 7. Using the example of the median filter shown in Fig. 9, the operation of the median filter can be easily demonstrated.
  • the input samples 50 are serially shifted into the input shift register 51.
  • the medial value is taken and used as the output.
  • the sampled data sequence in the register 51 is 1, 4, 6, 2, 9, 8, 5, 7, and 3.
  • the median filter selects 5 as the medial value. If a new input sample with a value 11 was input into the shift register 51, the end value 3 would be discarded and the input shift register 51 contents would become 11, 1, 4, 6, 2, 9, 8, 5, and 7. These would result in the output shift register contents becoming 1, 2, 4, 5, 6, 7, 8, 9, 11 after sorting.
  • the medial value output by the filter 54 would be 6 in this case.
  • sirens detectors Three basic types of sirens detectors are used for the detection of most sirens. The main objective of these schemes is to provide a low probability of false detection, fairly fast detection and classification time of about 2 to 3 seconds maximum, and sufficient flexibility to accommodate variations in the siren characteristics.
  • a common core siren detector is shown in Fig. 10, serving as the basis for the detection of yelp, wail, high-low, and other siren types.
  • the first of these is the most general and is suitable for yelp siren, although other siren types could also be detected. It simply sets a frequency threshold comparator 61 with a frequency threshold f thresh midway between the minimum and maximum frequencies expected for a yelp siren, which is about 900 to 1000 Hertz. The period between times when the increasing frequency wave shape crosses the threshold for two successive threshold crossing is measured by 62. If this period falls within the user selected range for valid yelp sirens which is typically 0.27 seconds to 0.40 seconds, and the frequency of the siren signal is greater than a selectable minimum frequency f min and less than a selectable maximum frequency f max , a counter is incremented.
  • the frequency comparators 63 and 64 are used for the purpose of frequency comparison. If the next period is measured to be within the user selected region, the counter is incremented again. If the next period is measured to be outside of the user selected range, the counter is decremented. The counter minimum value is 0. If the counter level exceeds a user selected threshold, typically 3 or 4 for reliable detection, then the yelp detector output is enabled to indicate that a siren meeting the yelp detection has been detected. It should be apparent that the sense of the change in frequency from an increasing in time sense to a decreasing in time sense in relation to the frequency threshold crossings is also possible within the context of this invention. This means may also be used for the high-low siren type, since this siren type is characterized by its periodic two frequency characteristic. The period measurement technique is shown in Fig. 12.
  • the second of these is also suitable for high-low siren, although other siren types could also be detected. It simply sets a frequency difference threshold midway between the difference of the minimum and maximum frequencies expected for a high-low siren, which is about 100 to 150 Hertz.
  • the frequency comparator 61 is then used to determine if the step in frequency between the low tone and the high tone exceeds some threshold f thresh . The period between times when the increasing frequency wave shape crosses the threshold for two successive increasing frequency crossings is measured.
  • a counter is incremented.
  • the frequency comparators 63 and 64 are used for the purpose of frequency comparison. If the next period is measured to be within the user selected region, the counter is incremented again. If the next period is measured to be outside of the user selected range, the counter is decremented.
  • the counter minimum value is 0 and typically has a maximum value of less than 20.
  • the high-low detector output is enabled to indicate that a siren meeting the high-low detection has been detected. It should be apparent that the sense of the change in frequency from an increasing in time sense to a decreasing in time sense in relation to the frequency threshold crossings is also possible within the context of this invention.
  • the period measurement technique is shown in Fig. 13.
  • the third siren detector type is for the wail siren.
  • This siren type is characterized by a very long period of between 4.8 and 7.2 seconds. It is readily apparent that if three to four complete cycles of a wail waveform were to be detected before the wail detect output were enabled, a detection time of about 15 or 20 seconds to 22 to 29 seconds would be required. This greatly exceeds the desired 2 to 3 seconds detection time. In fact, a siren equipped vehicle could easily be passed the intersection before the siren would have been detected. This highly undesirable situation is alleviated by observing the fact that the frequency characteristic is more or less a triangle wave with fairly straight portions to the curve.
  • the Wail siren detector uses this fact, and uses a short duration sliding window of about 1.0 seconds in duration to perform a linear least squares fit to the sampled frequency data.
  • f is the frequency
  • t is the time
  • m is the slope of the line or rate of change of frequency
  • Also calculated is the linear correlation coefficient of the fit between the straight line segment and the samples of data.
  • This linear least squares fit to the waveform and the frequency at any part of the waveform provide three classification criteria for the wail siren. These criteria are; (1) the frequency of the waveform must be with the user specified minimum and maximum frequencies as determined by comparators 63 and 64, (2) the rate of change of the frequency with time or slope of the straight line portion of the curves must fall within two user defined ranges, typically between ⁇ 300 Hz/sec to ⁇ 500 Hz/sec, as determined by the slope detector 65, and (3) the goodness of fit or correlation coefficient of the piecewise linear line segment to the frequency waveform as determined by the slope detector 65, with the magnitude of a good linear correlation coefficient typically being between 0.95 and 1.0. If the siren meets all three of these criteria, it can be reliably classified as a wail siren type.
  • Typical detection times using this technique are the order of 2 to 3 seconds, making it as reliable as the yelp siren detection technique.
  • the slope measurement technique is shown in Fig. 14.
  • the slope m of the wail siren sound shown in Fig 8 is shown in Fig. 15, and the linear correlation coefficient r is shown in Fig. 16.
  • the sample rate was 40 Hertz and 40 sample points were used for the linear fit. This fit was performed at a rate of 40 Hertz.
  • squelch detector One common type of squelch detector is based on a noise operated squelch detector. This detector provides a signal which is a function of the baseband SNR of the limiter-discriminator output. It is described in detail by Rhode and Ulrich in “Communications Receivers: Principles & Design", McGraw-Hill Book Company, 1988. The operation of these noise detectors is based on the fact that as the carrier to noise ratio increases, the baseband noise energy density decreases. This detector used for this purpose is shown schematically in Fig. 11. The output of the 1.5 kHz to 1.8 kHz bandpass filter is "full-wave rectified" by the Absolute value block. This output is then filtered by a simple low pass filter with a bandwidth of about 10 Hertz.
  • the output of this filter is then decimated to a rate of 40 Hertz, reducing the subsequent processing rates.
  • the decimated output which is a function of the signal to noise ratio of the squelch input signal, is then compared against a user selected threshold and the threshold detector output enabled when the input signal is below the threshold level.
  • the siren detector described in this invention is ideally suited for implementation in a programmable computing device or digital signal processor. This has the many advantages over analog implementations, such as little if any effect of temperature on the performance, ease of adapting the siren detector to new siren sounds by reprogramming rather than modifications to the hardware, the ability to remotely reprogram the siren detector for new siren sounds, the ability to remotely control the siren detector, etc.
  • This preferred implementation is shown in Fig 17.
  • the input signals from the input transducers are input to the Analog Input Signal Protection, Amplification, and Filtering section 80 to provide electrical transient protection and signal conditioning.
  • the signal processor 81 performs the analog to digital conversions and all of the processing functions described in this invention.
  • Status indicators provide feedback to users as to the performance of the siren detector, detection of valid siren sounds, siren type, channel number activated, etc.
  • Parameter input selectors 84 are provided to allow adjustment of the siren detection parameters locally.
  • An External Programming and Control Input Port 85 is provided to allow local or remote reprogramming of the siren detector to update the software control program, or to locally or remotely change the siren detection parameters.

Landscapes

  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Alarm Systems (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Traffic Control Systems (AREA)

Claims (24)

  1. Détecteur de sirène destiné à détecter des sons de sirènes, qui s'exécutent à des vitesses connues à l'intérieur d'une bande de fréquences sélectionnée, pour faciliter la commande anticipée de feux de signalisation pour permettre à un véhicule de secours de traverser un carrefour sur une base prioritaire, ledit détecteur comprenant des moyens formant transducteur (1) pour détecter lesdits sons et pour produire un signal électrique de sortie de son représentant ceux-ci, des premiers moyens de filtrage (3) pour filtrer ledit signal de sortie de son pour produire un signal de sortie antirepliement pour empêcher un repliement dans un processus ultérieur de conversion analogique-numérique, et des deuxièmes moyens de filtrage (5) pour produire un signal limité en bande en filtrant ledit signal de sortie antirepliement pour rejeter les signaux extérieurs à ladite bande de fréquences sélectionnée ; ledit détecteur étant caractérisé par des moyens formant limiteur-discriminateur (6) pour appliquer ledit signal limité en bande sur le plan complexe, pour calculer une quantité proportionnelle à la dérivée d'une portion de phase dudit signal limité en bande, et pour normaliser la quantité résultante pour produire une indication de la fréquence dudit signal limité en bande.
  2. Détecteur de sirène selon la revendication 1, comprenant en outre un filtre de craquement (8) sensible à ladite composante de fréquence pour supprimer les composantes de bruit impulsionnel de celle-ci pour produire un signal de sortie de discriminateur filtré.
  3. Détecteur de sirène selon la revendication 1, comprenant en outre des moyens de détection de niveau de son (14) sensibles audit signal limité en bande pour produire un signal de niveau de son indiquant qu'un niveau de son situé à l'intérieur de ladite bande de fréquences sélectionnée au niveau desdits moyens formant transducteurs dépasse un niveau d'intensité de son sélectionné.
  4. Détecteur de sirène selon la revendication 1, comprenant en outre des moyens de détection de silencieux (13) sensibles à ladite composante de fréquence pour indiquer qu'un niveau signal/bruit situé à l'intérieur de ladite bande de fréquences sélectionnée au niveau desdits moyens de transducteur dépasse un niveau signal/bruit sélectionné.
  5. Détecteur de sirène selon la revendication 1, comprenant en outre des moyens (62) sensibles à ladite composante de fréquence pour mesurer une période dudit son de sirène et pour fournir une indication du fait que ladite période se trouve dans une plage pouvant être sélectionnée.
  6. Détecteur de sirène selon la revendication 2, comprenant en outre des moyens (62) sensibles à ladite composante de fréquence pour mesurer une période dudit son de sirène et pour fournir une indication du fait que ladite période mesurée se trouve à l'intérieur d'une plage pouvant être sélectionnée.
  7. Détecteur de sirène selon la revendication 5, comprenant en outre des moyens (63, 64) sensibles à ladite composante de fréquence pour mesurer une fréquence dudit son de sirène et pour fournir une indication du fait que ladite fréquence mesurée se trouve à l'intérieur d'une plage pouvant être sélectionnée.
  8. Détecteur de sirène selon la revendication 6, comprenant en outre des moyens (63, 64) sensibles à ladite composante de fréquence pour mesurer une fréquence dudit son de sirène et pour fournir une indication du fait que ladite fréquence mesurée se trouve à l'intérieur d'une plage pouvant être sélectionnée.
  9. Détecteur de sirène selon la revendication 1, comprenant en outre des moyens (65) sensibles à ladite composante de fréquence pour mesurer une vitesse de variation de fréquence dudit son de sirène et pour fournir une indication du fait que ladite vitesse de variation de fréquence mesurée se trouve à l'intérieur d'une plage pouvant être sélectionnée.
  10. Détecteur de sirène selon la revendication 2, comprenant en outre des moyens (65) sensibles à ladite composante de fréquence pour mesurer une vitesse de variation de fréquence dudit son de sirène et pour fournir une indication du fait que ladite vitesse de variation de fréquence mesurée se trouve à l'intérieur d'une plage pouvant être sélectionnée.
  11. Détecteur de sirène selon la revendication 1, comprenant en outre des moyens (65) pour déterminer un coefficient de corrélation fournissant une mesure de corrélation entre la vitesse d'anticipation dudit son de sirène et une ligne droite et pour fournir une indication du fait que ledit coefficient de corrélation dépasse une valeur pouvant être sélectionnée.
  12. Détecteur de sirène selon la revendication 2, comprenant en outre des moyens (65) pour déterminer un coefficient de corrélation fournissant une mesure de corrélation entre la vitesse d'anticipation dudit son de sirène et une ligne droite et pour fournir une indication du fait que ledit coefficient de corrélation dépasse une valeur pouvant être sélectionnée.
  13. Détecteur de sirène selon la revendication 4, comprenant en outre des moyens de commande d'anticipation (15) pour produire un signal de sortie d'anticipation pour anticiper la commande desdits feux de signalisation en réponse aux signaux desdits détecteur de silencieux, détecteur de niveau de son et détecteur de sirène, tandis que lesdits moyens de commande d'anticipation activent un système de commande de feux de signalisation.
  14. Détecteur de sirène selon la revendication 7, comprenant en outre des moyens (15) pour produire un signal de sortie d'anticipation destiné à être appliqué à l'entrée d'un contrôleur de feux de signalisation lorsque ledit son de sirène augmente de niveau au-dessus d'un seuil pouvant être sélectionné et pour désactiver ledit signal de sortie d'anticipation lorsque ledit son de sirène diminue de niveau au-dessous d'un seuil pouvant être sélectionné.
  15. Détecteur de sirène selon la revendication 8, comprenant en outre des moyens (15) pour produire un signal de sortie d'anticipation destiné à être appliqué à l'entrée d'un contrôleur de feux de signalisation lorsque ledit son de sirène augmente de niveau au-dessus d'un seuil pouvant être sélectionné, pour désactiver ledit signal de sortie d'anticipation lorsque ledit son de sirène diminue de niveau au-dessous d'un seuil pouvant être sélectionné, et pour maintenir ledit signal de sortie d'anticipation dans un état activé pendant une durée pouvant être sélectionnée.
  16. Détecteur de sirène selon la revendication 1, dans lequel ledit détecteur de sirène est mis en oeuvre dans un processeur de signal programmable (81) actionné conformément à un programme informatique, ledit processeur de signal programmable comportant un point d'accès de communications (85) permettant audit programme informatique d'être chargé de l'extérieur depuis une source de programmation externe.
  17. Détecteur de sirène selon la revendication 16, dans lequel ladite source de programmation externe est située à distance.
  18. Détecteur de sirène destiné à détecter, conformément à des paramètres sélectionnés par un utilisateur, un son de sirène qui s'exécute à une vitesse connue à l'intérieur d'une bande de fréquences sélectionnée pour faciliter la commande anticipée de feux de signalisation commandés par un contrôleur de feux de signalisation, pour permettre à un véhicule de secours de traverser un carrefour sur une base prioritaire, ledit détecteur comprenant
    (a) des moyens formant transducteur (1) pour détecter ledit son et pour produire un signal électrique de sortie de son représentant celui-ci ;
    (b) des premiers moyens de filtrage (3) pour produire un signal antirepliement en filtrant ledit signal de sortie de son pour empêcher un repliement dans un processus ultérieur de conversion analogique-numérique ;
    (c) des deuxièmes moyens de filtrage (5) pour produire un signal limité en bande en filtrant ledit signal antirepliement pour rejeter les signaux extérieurs à la bande de fréquences sélectionnée ; ledit détecteur étant caractérisé par
    (d) un limiteur-discriminateur (6) pour traiter ledit signal limité en bande, pour délivrer un signal de sortie de discriminateur ayant un grand nombre de niveaux de signal possibles, chacun d'entre eux indiquant une fréquence différente dudit signal de sortie de son.
  19. Détecteur de sirène selon la revendication 18, dans lequel ledit détecteur de sirène est mis en oeuvre dans un processeur de signal programmable (81) actionné conformément à un programme informatique, ledit processeur de signal programmable comportant un point d'accès de communications (85) permettant de charger de l'extérieur des paramètres pouvant être sélectionnés par un utilisateur, depuis une source de programmation externe.
  20. Détecteur de sirène selon la revendication 19, dans lequel ladite source de programmation externe est située à distance.
  21. Détecteur de sirène selon la revendication 2, dans lequel ledit filtre de craquement (8) est un filtre médian.
  22. Détecteur de sirène selon la revendication 3, comprenant en outre des moyens de détection de silencieux (13) sensibles à ladite composante de fréquence pour produire un signal de détecteur de silencieux indiquant qu'un niveau signal/bruit situé à l'intérieur de ladite bande de fréquences sélectionnée au niveau dudit transducteur d'entrée dépasse un niveau signal/bruit sélectionné.
  23. Détecteur de sirène selon la revendication 22, comprenant en outre des moyens (62) sensibles à ladite composante de fréquence pour mesurer une période dudit son de sirène et pour fournir une indication du fait que ladite période mesurée se trouve à l'intérieur d'une plage pouvant être sélectionnée.
  24. Détecteur de sirène selon la revendication 23, comprenant en outre des moyens de commande d'anticipation (15) pour produire un signal de sortie d'anticipation pour anticiper la commande desdits feux de signalisation en réponse aux signaux desdits détecteur de silencieux, détecteur de niveau de son et détecteur de sirène, tandis que lesdits moyens de commande d'anticipation activent un système de commande de feux de signalisation.
EP94908234A 1994-03-04 1994-03-04 Detecteur de sirene Expired - Lifetime EP0748494B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT94908234T ATE167584T1 (de) 1994-03-04 1994-03-04 Sirenendetektor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CA1994/000119 WO1995024028A1 (fr) 1994-03-04 1994-03-04 Detecteur de sirene

Publications (2)

Publication Number Publication Date
EP0748494A1 EP0748494A1 (fr) 1996-12-18
EP0748494B1 true EP0748494B1 (fr) 1998-06-17

Family

ID=4173012

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94908234A Expired - Lifetime EP0748494B1 (fr) 1994-03-04 1994-03-04 Detecteur de sirene

Country Status (7)

Country Link
EP (1) EP0748494B1 (fr)
JP (1) JPH09512902A (fr)
CA (1) CA2183868C (fr)
DE (1) DE69411195T2 (fr)
HK (1) HK1009352A1 (fr)
NZ (1) NZ262083A (fr)
WO (1) WO1995024028A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6133849A (en) * 1996-02-20 2000-10-17 Unity Wireless Systems Corporation Control signal coding and detection in the audible and inaudible ranges
WO2009021902A1 (fr) * 2007-08-16 2009-02-19 Siemens Aktiengesellschaft Procédé et dispositif pour donner la priorité à des véhicules spéciaux à un carrefour réglé par des feux de signalisation
CN102867424B (zh) * 2012-09-26 2014-07-30 杭州鼎鹏交通科技有限公司 一种区域协调交通控制方法
EP3753003A1 (fr) * 2018-02-13 2020-12-23 Premel SA Dispositif électronique de détection d'événements pour la régulation du trafic, et procédé correspondant

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2027243B (en) * 1978-07-27 1982-10-13 Marconi Co Ltd Priority vehicle control of traffic signalling system
US4864297A (en) * 1987-10-14 1989-09-05 Tekedge Development Corp. Siren detector
US4806931A (en) * 1988-01-25 1989-02-21 Richard W. Clark Sound pattern discrimination system
US4956866A (en) * 1989-06-30 1990-09-11 Sy/Lert System Ltd. Emergency signal warning system

Also Published As

Publication number Publication date
CA2183868A1 (fr) 1995-09-08
AU6152694A (en) 1995-09-18
NZ262083A (en) 1998-05-27
DE69411195T2 (de) 1999-02-04
WO1995024028A1 (fr) 1995-09-08
EP0748494A1 (fr) 1996-12-18
CA2183868C (fr) 2002-01-15
JPH09512902A (ja) 1997-12-22
AU681380B2 (en) 1997-08-28
HK1009352A1 (en) 1999-05-28
DE69411195D1 (de) 1998-07-23

Similar Documents

Publication Publication Date Title
US5710555A (en) Siren detector
US4759069A (en) Emergency signal warning system
US5287411A (en) System for detecting the siren of an approaching emergency vehicle
US6229439B1 (en) System and method of filtering
US5455868A (en) Gunshot detector
US5867581A (en) Hearing aid
US5146226A (en) Motor vehicle police radar detector for detecting multiple radar sources
US5206651A (en) Motor vehicle police radar detector for detecting multiple radar sources
US8823548B2 (en) Control of traffic signal phases
US5250951A (en) Motor vehicle police radar detector for detecting multiple radar sources
US6229997B1 (en) Interference detecting receiver
US7123145B2 (en) Method and apparatus for analysing a signal from a movement detector for determining if movement has been detected in an area under surveillance and an anti-theft system
US6631096B2 (en) Method and apparatus for detecting intrusion and non-intrusion events
EP0318668B1 (fr) Détecteur de sirène
US20180074164A1 (en) Device for warning of radar traps
CA2116043C (fr) Detecteur de tonalites de progression d'appel numerique programmable
EP0748494B1 (fr) Detecteur de sirene
US6469653B1 (en) Apparatus and method for selectively monitoring radar signals and providing an alert responsive thereto
CN1054226C (zh) 警报检测器
AU681380C (en) Siren detector
JPH023126B2 (fr)
CA1333100C (fr) Dispositif detecteur de signaux d'alarme et avertisseur
KR830002735B1 (ko) 초음파 경계장치
GB2278984A (en) Speech presence detector
GB2182474A (en) Intruder detector signal processing

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19960909

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: SI PAYMENT 960909

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

17Q First examination report despatched

Effective date: 19970429

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE

AX Request for extension of the european patent

Free format text: SI PAYMENT 960909

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980617

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 19980617

Ref country code: GR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980617

Ref country code: ES

Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY

Effective date: 19980617

Ref country code: CH

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980617

Ref country code: BE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980617

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980617

REF Corresponds to:

Ref document number: 167584

Country of ref document: AT

Date of ref document: 19980715

Kind code of ref document: T

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REF Corresponds to:

Ref document number: 69411195

Country of ref document: DE

Date of ref document: 19980723

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980917

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980917

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980917

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

ET Fr: translation filed
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990304

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990304

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990930

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19991001

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 19991001

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20050302

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20050321

Year of fee payment: 12

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20050502

Year of fee payment: 12

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060304

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20061003

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20060304

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20061130

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060331