EP1189479A1

EP1189479A1 - Wireless transmission communication system

Info

Publication number: EP1189479A1
Application number: EP00610093A
Authority: EP
Inventors: Keith Lam
Original assignee: Phonic Ear Inc
Current assignee: Frontrow Calypso LLC
Priority date: 2000-09-15
Filing date: 2000-09-15
Publication date: 2002-03-20

Abstract

The invention relates to communication system for infrared transmission of a signal from a non-stationary speaker to a sound reproducing system, the communication system comprising two microphones; at least one signal emitter; a receiver and end transmission equipment, where the microphones form part of a single portable unit suitable for placement around a wearers neck and where the microphones are placed with mutual angle in a fixed position in relation to the unit and at least one signal emitter is provided for the transmission of the signal to a remote signal receiver. The invention further relates to a microphone unit for use in such wireless communication systems.

Description

FIELD OF THE INVENTION

The invention relates to wireless communication systems. Such systems are well known within the art of transmitting a signal from an emitter to a receiver. The systems comprise both infrared communication systems and radio frequency communication systems.

BACKGROUND OF THE INVENTION

A previously known system comprises a stationary microphone for transforming an acoustical signal to an electrical signal, which is modulated for infrared transmission in modulating electronics. These electronics are connected to a stationary IR emitter, which transmits the modulated signal. An IR receiver, e.g. mounted in a headset or body-pack, is provided at each of the persons in the environment desiring to receive the emitted signal. The received signal is demodulated in demodulating electronics and transferred to the earphones worn by the listener. The receivers and connected demodulating electronics may be connected to various other types of transmission equipment, such as loudspeakers via external amplification systems
Further a system is known, which comprises a handheld microphone/emitter unit. This means that the speaker is unable to use both hands and at the same time hold the microphone in a correct position. This is inconvenient in many situations, i.e. in an education environment.
It is obvious that such system will only provide a satisfying functionality in the situation where the speaker is in a stationary position, meaning that such systems may be sufficient for conference purposes. However a number of situations may be set forth where the stationary system is insufficient, due to the speakers need of moving into different positions. One very important situation is the education situation in schools, universities and similar.
Many systems comprise a clip on type microphone, this type of microphone would pick up background noise and is also very prone to acoustic feedback. In an education environment the speaker has to move his/her head from side to side, which means that the sound pressure to the microphone often will be weak, resulting in a weak signal and hence in a poor intelligibility for the students. Furthermore headsets are known, which are mounted on the head of the speaker and where the microphone is mounted on a boom. These headsets are undesirable due to the head mounting, as many find that they interfere with the hair of the wearer and generally are uncomfortable. Another microphone system that is on the market is the Collar™ microphone from Anchor. They use only one microphone. The problem with this Collar™ microphone is the variation in input sound pressure level when the wearer rotates his/her head from side to side.
As described above in connection with the previously known wireless communication systems there exist several drawbacks, especially under conditions where the speaker has to move around, i.e. in an education environment, or has to move his/her head to the side. Therefore there is a need of improving such wireless transmission systems for use by non-stationary speakers.
In one aspect it is an object of the present invention to provide a wireless communication system, which allows the speaker to move his/her head from side to side without influencing the microphone input signal significantly. It is a further object to provide a wireless communication system having a microphone unit, which does not interfere with the hair of the speaker and which allows the speaker to use both hands and speak simultaneously. In another aspect it is an objective of the present invention is to provide a microphone unit for use in connection with a wireless communication system, which provides the advantages of allowing the speaker to move his/her head from side to side without influencing the microphone input signal significantly. It is another object of the invention to provide a microphone unit, which does not interfere with the hair of the speaker and which allows the speaker to use both hands and speak simultaneously.

SUMMARY OF THE INVENTION

According to the invention this is achieved by means of a system comprising: A communication system with a portable part and a stationary part, the portable part comprising at least two microphones for receiving the wearers voice, modulation electronics in connection with the microphones for modulating the microphone signal, at least one signal emitter in connection with the modulating electronics adapted for transmitting the modulated microphone signal, the stationary part comprising, at least one receiver for receiving the transmitted modulated microphone signal, demodulating electronics in connection with the at least one receiver. End transmission equipment, where the two microphones form part of a single portable unit suitable for placement around a wearers neck, where the unit comprises a flexible carrier element having a free end, where at least two microphones are placed in a fixed position in relation to the flexible carrier element, with an angle between the main direction of at least two microphones in the range of 30-180 degrees. The angle is in a preferred embodiment in a range of 60-120 degrees, and even more advantageous approximately 90 degrees.
Since the microphones are placed in a fixed position with mutual angular distance it is possible to provide an optimal positioning in front of the wearer's mouth independent of the wearer's position of the head, hereby being able to provide a proper microphone input signal independent of the position of the wearer's head. As the microphones form part of a single unit they are put on in a single operation which facilitates the use of the system. The receiver(s) may be stationary or portable. The end receiver equipment may comprise one or more loudspeakers or as an alternative portable loudspeaker headsets.
In a preferred embodiment the at least two microphones are connected in series, hereby reducing their sensitivity and hence lessen mechanical noise, e.g. clothing noise or rubbing noise.
In one embodiment an IR emitter is provided as a signal emitter. In a preferred embodiment at least two IR emitting means are provided, where these two means are positioned on the unit to cover different transmission areas. Hereby the blocking of the IR signals is reduced significantly.
Preferably the two IR emitting means are electrically connected in parallel. Hereby power consumption and circuit size are reduced.
In a still further preferred embodiment three IR emitting means are provided. Preferably all the IR emitting means are electrically connected in parallel. The three IR means provides for an even more improved area coverage. Moreover the presence of three means provides for backup in case of failure of one of the IR means.
The invention further relates to a microphone unit for use in a wireless transmission communication system, the microphone unit comprising at least two microphones for receiving a wearers voice; at least one signal emitting means; where the unit comprises a flexible carrier element having a free end; where the at least two microphones are placed in a fixed position in relation to the flexible carrier element, with an angle between the main direction of the at least two microphones in the range of 30-180 degrees.
In one embodiment an IR emitter is provided as a signal emitter. In a preferred embodiment at least two IR emitting means are provided, where these two means are positioned to cover different transmission areas. The two IR emitting means are advantageously electrically connected in parallel. In another preferred embodiment an antenna is provided as a signal emitter for transmission of RF signals, preferably FM signals. As the effect of the two-microphone unit is not dependent of the sort of transmission equipment this alternative embodiment will provide the same benefits for an RF transmission system as for an IR transmission system.
The microphones are in the preferred embodiment placed on the unit in such a manner that they are distanced from the chest of the wearer, preferably at positions close to the wearer's mouth. Hereby the microphones are optimally positioned for reception of the wearer's voice. The IR emitting means may be positioned adjacent to the microphones or along the flexible element.
In a preferred embodiment at least two microphones are connected in series, hereby reducing their sensitivity and hence lessen mechanical noise, e.g. clothing noise or rubbing noise.
Besides IR emitting means and corresponding modulating electronics a RF transmitting equipment may be used. Modulating electronics, preferably FM electronics although other may be used, and an antenna hereby will provide for the transmission.
On the microphones, the angle serves as a function of providing a more uniform reception of the signal that coming from the speaker mouth. The microphones are preferably directional microphones, and they are built to differentiate sound pressure coming from the front or from behind (mechanical delay). Each microphone element has a particular coverage pattern, i.e. cardioid for unidirectional microphone. Putting the two microphones together in this fashion would create a new pattern of response. In this case the pattern is preferably shaped to cover the horizontal head rotation of the wearer, which is about 30 degrees on either side of the normal head position (facing straight ahead). Additionally, by the use of directional microphone elements, feedback would be lessen compares to a unidirectional microphones. The angle between the microphones can be changed depending the microphone elements used. Each microphone preferably has its own inlets, front and back, and each microphone has its own acoustic chamber even though they are preferably placed in the same housing. Hereby the housing is molded so that it has two separate chambers.
The curved element is preferably manufactured from a flexible material allowing the element to be flexed in a manner, which allows placement around the neck of the wearer and positioning of the microphones in a correct position in front of the wearer's mouth. In this resting position the microphones are in a suitable position for receiving the wearer voice signals. Further advantageous the element may be shaped to lock around itself upon bending or flexing, hereby constituting a loop around the wearer's neck. Hereby the placement is further secured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a communication system according to the invention;
FIG. 2 is a perspective view of a portable microphone unit according to the invention;
FIG. 3 is a front view of a microphone housing of the unit according to the invention;
FIG. 4 is a top view of the microphone housing of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

From FIG. 1 a communication system appears, which comprises a speaker side system and a listener side system.
The speaker side system comprises a microphone unit comprising two microphones 1,2 and two infrared (IR) LED's 8,9 mounted on a collar. The unit is described more detailed in connection with Fig.2 and Fig. 3. The microphone input signals are transferred to a modulating system 5 through wires 3,4 and after modulation from the modulating system 5 through wires 6,7 to the LED's 8,9 which emit the signal towards the listener side system. The speaker side system is powered by batteries.
The listener side system comprises two receivers 10,11 (further receivers may be provided), a demodulating system 12, an amplifier 13 and one or more speakers 14,15 for outputting the received, demodulated and possibly amplified signal. The listener side system may be powered either by a battery or by any other available electrical power source. The listener side system may be stationary, portable or a combination of these.
The modulating and demodulating electronics are well known within the art of wireless transmission in the IR and in the RF area.
From FIG. 2 a microphone unit according to the invention appears in a front view. It appears that the microphone unit comprises a curved element 16 having a free end with a microphone housing 17, which is intended to be located in front of the wearers mouth when the microphone unit is mounted. The two microphones 1,2 are mounted at the free end in such manner that the microphones preferably have a mutual angle of between 30 and 180 degrees. This may however vary dependent of the characteristics of the microphones. The LED's 19 are placed in a housing 18 mounted on the flexible element 16. The LED's are only relevant in the embodiment using infrared transmission technology. Instead a RF, preferably FM type, signal-transmitting equipment may be utilized. A switch is shown in the housing 18. This is intended as a mute switch, preferably for use in an FM system, although in this drawing it has been shown together with the IR emitting means. From the housing 18 a wire 21 extends to a box 22 containing modulating electronics as well as transmitting electronics. Indicators 24 as well as channels selector button 23 are shown in the drawing.
From FIG. 3 the microphone housing 17 appears seen from the side. It appears that the housing is mounted at the free end of the flexible gooseneck element 21. A part 26 of the housing containing one microphone is indicated in the drawing.
From FIG. 4 the microphone housing 17 appears seen from the top. It appears that the microphones are placed in protruding angular spaced parts 25,26 of the housing. The angle of the microphones is shown as 27. The angle is in the shown embodiment about 45 degrees. This means that the angle between the microphone is about 90 degrees. The bending may be effected individually as the curved element preferably comprises a goose-neck material, which is commonly known for other purposes. A soft metal like copper may be utilized having essentially the same effect, although this will inherently posses the disadvantage of being quite heavy compared with typical goose-neck materials. It should be appreciated that by the term goose-neck material any material or combination of material is meant, which are adapted for bending into a preferred position or shape and are adapted for maintaining this shape until a further bending operation is performed

Claims

A communication system a portable part and a stationary part, the portable part comprising:

at least two microphones for receiving the wearers voice;

modulation electronics in connection with the microphones for modulating the microphone signal;

at least one signal emitter in connection with the modulating electronics adapted for transmitting the modulated microphone signal;

the stationary part comprising:

at least one receiver for receiving the transmitted modulated microphone signal;

demodulating electronics in connection with the at least one receiver;

end transmission equipment;

where the two microphones form part of a single portable unit suitable for placement around a wearers neck;

where the unit comprises a flexible carrier element having a free end.
A system according to claim 1, where the at least two microphones are placed in a fixed position in relation to the flexible carrier element, with an angle between the main direction of the at least two microphones in the range of 30-180 degrees.
A system according to claim 1, where the at least two microphones are connected in series.
A system according to claim 1, where at least one IR emitting means is provided as a signal emitter.
A system according to claim 4, where two IR emitting means are electrically connected in parallel.
A system according to claim 1, where RF transmission equipment is provided, the equipment comprising an antenna as a signal emitter for transmission of RF signals, preferably FM signals.
A portable microphone unit for use in wireless transmission communication system, the microphone unit comprising at least two microphones for receiving a wearers voice; at least one signal emitting means; where the unit comprises a flexible carrier element having a free end; where the at least two microphones are placed in a fixed position in relation to the flexible carrier element,
A portable microphone unit according to claim 7, where the at least two microphones are provided with an angle in the range of 30-180 degrees.
A portable microphone unit according to claim 7, where the at least two microphones are connected in series.
A portable microphone unit according to claim 7, comprising a single housing for the two microphones.
A portable microphone unit according to claim 7, where at least one IR emitting means is provided as signal emitter.
A portable microphone units according to claim 9, where two IR emitting means are electrically connected in parallel.
A portable microphone unit according to claim 7, where RF transmission equipment is provided, the equipment comprising an antenna a signal emitter for transmission of RF signals, preferably FM signals.
A portable microphone unit according to claim 7, where the flexible element comprises a goose-neck material adapted to take several different positions.
A portable microphone unit according to claim 7, where the flexible element comprises a soft metal rod, e.g. copper, adapted to take several different positions.
A portable microphone unit for use in wireless transmission communication system, the microphone unit comprising at least one microphone for receiving a wearers voice; at least one signal emitting means; where the unit comprises a flexible carrier element having a free end; where the at least one microphone is placed in a fixed position in relation to the flexible carrier element, said carrier element being adapted for bending into a preferred shape and maintaining this shape until a further bending operation is carried out.