FR2770075A1 - PERFECTED MICROPHONE DEVICE FOR HELMETS, AND HELMETS EQUIPPED WITH SUCH DEVICE - Google Patents

Abstract

This motorcycle helmet microphone device associated with means for filtering and amplifying the output signals of the microphone to be transmitted, is characterized in that it comprises at least one transducer (9), arranged in the interior lining ( 5) of the headphones and an automatic gain control circuit of the amplification means according to the conditions of reception of the acoustic signals picked up by the transducer.

Description

The present invention relates to helmets and relates more

  especially to motorcycle helmets

  such as those commonly used by the traffic police.

  Motorcycle police officers generally need to communicate either with each other or with their base such as a command vehicle or with their headquarters.

  For this purpose their vehicles are provided with a

  radio with microphone and headphones available

  in the user's helmet to allow them to

  communicate with the other parties while driving.

  Known equipment of this type uses special microphones called osteophones which capture the vibrations of the user's headbox when

this one speaks.

  The osteophone, placed inside the helmet shell in contact with the user's head is connected

to a transmitter.

  Osteophones have the disadvantage of being little

  selective so that they not only pick up the vibra-

  tions of the skull generated by the speech of

  user, but also external and internal noise

  headphones caused by the wind when the motorcyclist

exceeds a determined speed.

  Thus, the program obtained using an osteophone

  is made unusable at high speed because the

  general to be transmitted is made unintelligible due in particular to

  ment of the loss of the lips of the word.

  The invention aims to remedy this drawback by

  creating a microphone device for a motorcycle helmet

  cliste which retains its signal transmission performance

  both at standstill and at high speeds of the motorcycle

  clette driven by the helmet user.

  It therefore relates to a microphone device for a motorcycle helmet associated with means for filtering and amplifying the microphone output signals to

  transmit, characterized in that it comprises at least one trans-

  conductor, arranged in the interior lining of the helmet and a

  automatic gain control circuit for amplification means

  fication according to signal reception conditions

  acoustics picked up by the transducer.

  The invention will be better understood on reading the

  description which follows, with reference to the drawings

  attached, given only by way of example and on-

  which: Fig. 1 is a schematic perspective view with

  partial removal of a helmet fitted with a half-device

  crophone according to the invention; Fig.2 is a partial sectional view at more

  large scale showing the arrangement of the mid-

  crophone according to the invention in the helmet of Fig.l;

  Fig. 3 is a block diagram of the wire circuit-

  trage and amplification associated with the transducer of the device

  tif of the microphone in Fig. 1; Fig.4 is a schematic view of a helmet equipped with another embodiment of the microphone device according to the invention and

  Fig. 5 is a block diagram of the wire circuit-

  trage and amplification associated with the microphone device

in Fig. 4.

  In Fig. 1 there is shown in perspective a case-

  1 motorcyclist with a hinged chin strap 2

on helmet 1 by axes 3.

  The shell of the helmet 1 has an outer casing

  rigid 4 lined with an interior covering 5.

  The shell has an anterior opening 6 for the

user face.

  In the upper region 7 of the edge 8 of the opening

  6 is arranged a transducer 9 of a micro-device

phone according to the invention.

  In the embodiment of Fig. 11, this trans-

  conductor is arranged in the middle of the upper region 7 of the

edge 8 of the helmet opening.

  It is understood, however, that it could also be placed at another location in the upper region 7 or

  well still in one of the side parts 10 of this edge.

I l I I l, ....

  Furthermore it is also possible to consider

  the use of several transducers arranged in relation

  wearing an axial plane of the helmet, so that by processing the signals from these transducers by their phase difference, a direction of the acoustic signal is favored. Advantageously and in no way limitative the or

  the transducers are of the electret type.

  The transducer 9 is connected to an electro-

  filter 11 and amplification of the transducer signals. This circuit 11 is in turn connected to a

  transceiver. 12 via line 13.

  The transceiver 12 is advantageously arranged on the vehicle.

  Referring to Fig. 2 we see that the transducer

  tor 9 is disposed near the upper region 7 of the edge 8 of the interior of the polystyrene covering 5 of the helmet. It is engaged in a recess 15 formed in the front edge of the covering 5 with the interposition of a block

foam cushioning 16.

  The transducer is further protected by an element

  windbreaker 17 made of plastic. The whole thus constituted

killed is covered with a cloth 18.

  The covering 5 is connected at its front end with the front edge of the shell 4 by means of a seal 19 which maintains the fabric 18 between the shell 4

and dressing 5.

  As shown in Fig.3, the transducer 9 of the microphone device according to the invention is connected to an electronic circuit 11 for filtering and amplification. This

  circuit delimited by a mixed input line includes a circuit

  cooked 20 filtering the transducer output signal con-

  connected to its output and whose output is connected

  ted to a variable gain pre-amplifier circuit and

variable filtering 21.

  The output of this circuit 21 is connected by a circuit

  cooked 22 adaptation to the transceiver 12. The output of the

  adapter circuit 22 is connected by line 13 to the transmitter

  tor-receiver 12 as already indicated with reference to Fig. 1.

  Between the circuit 20 for filtering the output signals

  tie of the transducer and the preamplifier 21 is further connected a gain controller circuit 23 whose output is

  connected to a control input 24 of the pre-circuit

  variable gain amplifier and variable filter 21. The operation of microphone device which

  has just been described with reference to Fig. 1 to 3 is the following

  vant: The transducer 9 receives the speech signals emitted by the wearer of the helmet, part of these signals

  being returned by the chin rest 2 while a part

  bearing reaches the transducer directly.

  The transducer output signals are filtered by the filter circuit 20 and are applied on the one hand to the variable gain preamplifier 21 and on the other hand to the

gain controller 23.

  The controller 23 determines whether the signals transmitted by

  the transducer 9 and filtered by the circuit 20 have a qua-

  sufficient to be transmitted to the variable gain pre-amplifier with variable filtering without modifying the gain and the bandwidth of the pre-amplifier 21. If this is the case, the output signals of circuit 20 are transmitted by the gain amplifier variable and variable filtering at

  matching circuit 22 without neither the gain nor the band passing

  health 21 do not undergo modifications from the circuit

23.

  The output signals of the adapter circuit 22 are applied to the input of the transceiver 12 and emitted by

  the transmission part of this transceiver.

  If on the contrary, due to the operation of the transducer 9 in an unfavorable environment due to

  example of the use of the microphone system by the

  In order to avoid the helmet moving at high speed, the transducer 9 receives not only the speech signals from the wearer of the helmet but also the signals from external noises and

helmet interiors.

  The gain controller 23 detects this situation and adapts the gain and the bandwidth of the variable gain amplifier 21 with variable filtering so that it can compensate for the quality of the signals transmitted to

the transceiver 12.

  The microphone device which has just been described with reference to Fig. 1 to 3 applies equally to a helmet with a chin guard as to a helmet without a chin guard.

  In Fig. 4 a variant of arrangement is shown.

  microphone sitive according to the invention, according to which a helmet 21 of the chin type 22 articulated on the shell of the

  helmet 21 by means of pins 23 is provided in the upper part

  of its front opening 24 of a transducer 25 similar to that described with reference to FIGS. 2 and 3. As in the previous embodiment, the transducer 25 is connected by a line 26 to an amplification and filtering circuit or electronic card 27 which in turn is connected by a line 28 to an external transceiver 29 headphones. Advantageously, the helmet of FIG. 4 comprises

  in addition a visor 31 hinged also on the shell.

  The microphone device of Fig. 4 differs from that described above in that it further comprises a

  visor position detector 30 connected to the circuit

  cooked 27 amplification and filtering.

  The electronic circuit associated with the transducer 25

is shown in Fig. 5.

  It includes, as in the embodiment of FIG. 3, a circuit 32 for filtering and transmitting the output signal from the transducer 25. The output of the circuit 32 is

  connected to a variable gain and wire preamplifier

  variable trage 33 whose output is in turn connected to

an adapter circuit 34.

  The output of the latter is connected to the transmitter-

receiver 29.

  The visor position detector 30 is

  connected by its output to a circuit for shaping of

  gnal 35 connected to a preamplifier control input

  variable gain 33 via a function circuit

  tion of hysteresis 36 whose role is to fix for the de-

  activation of the preamplifier control 33 a different threshold depending on whether the visor 31 is open or folded down

on the user's face.

  The position detector 30, the shaping circuit 35 and the hysteresis circuit 36 perform the same function as that of the gain controller circuit 23 of the mode

Fig. 3.

  In the circuit of Fig. 5, the opening of the vi-

  helmet 31 is detected by the detector 30 which via the shaping circuit 35 and the circuit

  with hysteresis function 36 controls the gain and the pass band

  health of the variable gain pre-amplifier with variable filtering

  reliable 33 to adapt it to different environmental conditions due to the fact that the face of the user of the helmet may be entirely exposed or covered and therefore that the speech signals emitted by the user to the transducer 25 are accompanied by noises inside and outside the helmet especially when

  the user is traveling at high speed.

  However when closing the visor 31

  on the user's face, the helmet constitutes a

  girdle closed and the speech signals reach the

  transducer under different conditions and are trans-

  set by variable gain pre-amplifier and filtering

  variable to the transceiver 29. The position detector

  tion 30 which detects the closed position of the visor 31 lets the pre-amplifier 33 transmit the signals coming from the transducer 25 without causing any intervention

on its gain or its bandwidth.

  In the embodiments which have just been

  described the electronic card comprising the amplifier circuit

  fication and filtering on the one hand and the gain control circuit on the other hand is mounted in the helmet, for example

  in a housing for the covering thereof. We design this-

  while this electronic circuit can also be dis-

placed outside the helmet.

  Thanks to the arrangement which has just been described, the microphone device for headphones according to the invention has significantly improved performance compared to

existing devices.

Claims (8)

  1. Microphone device for motorcycle helmet   key associated with means of filtering and amplifying the output signals of the microphone to be emitted, characterized in that it comprises at least one transducer (9; 25), arranged in the interior covering (5) of the helmet and a circuit (23; 30; 35; 36) for automatic gain control of the amplification means (21; 33) according to the conditions   for receiving the acoustic signals picked up by the transducer tor.   2. Microphone device according to claim 1, characterized in that the transducer (9) is arranged   in the cover (5) of the helmet near the region above   of the edge (8) of the anterior opening (6) of said helmet.   3. Microphone device for motorcycle helmet   clette associated with filtering and amplification means   microphone output signals to be transmitted according to the re-   vendication 2, characterized in that the transducer (9; 25) is arranged in the covering (5) in the middle of the region   upper (7) of the edge (8) of the opening (6) of the helmet.   4. Microphone device according to claim 1, characterized in that the transducer (9) is arranged   in one of the lateral parts (10) of the edge (8) of the helmet green.   5. Microphone device according to one of the res-   dications 1 to 4, characterized in that the transducer (9)   is housed in a recess (15) formed in the front edge   laughing of the covering (5) of the helmet with interposition of a   foam cushioning block (16) and is furthermore   covered by a plastic windbreaker (17).   6. Microphone device according to one of the res-   dications 1 to 5, characterized in that the connection circuit   gain plate (23) is connected between a circuit (20) for filtering the transducer output signals (9) and a   variable gain amplifier circuit with variable filtering   reliable means of filtering and amplification.   7. Microphone device according to one of the res-   dications 1 to 5, characterized in that the helmet (21) being   gain comprises a detector (30) of the position of the vi-   channel (31), the output of said detector (30) being connected to the variable gain amplifier circuit with variable filtering (33) via a shaping circuit (35) and a circuit ( 36) with hysterisis function.   8. Helmet, in particular a motorcyclist's helmet characterized in that it is equipped with a microphone device   according to one of claims 1 to 8.