Patent Application
20080112573
1. Field of the Invention
The invention relates to a signal transmitting and receiving system, more particularly to a wireless signal transmitting and receiving system adapted for use in a cabin of a vehicle.
2. Description of the Related Art
Passenger vehicles, such as airplanes, are provided with wired headphone systems that enable passengers to listen to music or television programs by plugging signal terminals of passenger headsets into dedicated sockets on armrests of passenger seats.
To make a trip more comfortable, passengers are usually provided with pillows, blankets, and the like. Travel regulations also require passengers to buckle up their safety belts. With so many objects around, wires of the headsets can interfere with posture of passengers especially during meals in view of the limited space of passenger seats. There is thus a need for wireless headphone systems suitable for use in a cabin of a vehicle.
However, for traffic safety, the Federal Aviation Administration (FAA) imposes stringent restrictions on the amount of electromagnetic interference (EMI) radiated in a passenger cabin of an airplane. For this reason, conventional wireless headphone devices available for household use are unsuited for use in airplanes.
Therefore, the object of the present invention is to provide a signal transmitting and receiving system that is suitable for use in a cabin of an airplane.
According to one aspect of the present invention, there is provided a signal transmitting and receiving system that comprises a transmitting device and a receiving device. The transmitting device includes a first processing unit adapted for receiving signals from a signal source, a directional transmitting unit coupled to the first processing unit and operable so as to wirelessly transmit signals from the first processing unit along a primary signal transmitting direction, and a driving unit for coupling rotatably the directional transmitting unit to the first processing unit such that the primary signal transmitting direction is adjustable relative to the first processing unit. The receiving device includes a receiving unit for receiving the signals wirelessly transmitted by the directional transmitting unit, and a second processing unit coupled to the receiving unit for processing signals received therefrom.
According to another aspect of the present invention, there is provided a signal transmitting device that comprises a processing unit adapted for receiving signals from a signal source, a directional transmitting unit coupled to the processing unit and operable so as to wirelessly transmit signals from the processing unit along a primary signal transmitting direction, and a driving unit for coupling rotatably the directional transmitting unit to the processing unit such that the primary signal transmitting direction is adjustable relative to the processing unit.
According to yet another aspect of the present invention, there is provided a signal receiving device that comprises: a receiving unit including an infrared light receiver that is adapted for receiving wirelessly transmitted signals; a processing unit coupled to the receiving unit for processing signals received therefrom; a speaker unit connected to the processing unit for receiving and reproducing the signals processed by the processing unit; and a headphone housing that has the receiving unit, the processing unit and the speaker unit mounted therein, the headphone housing having a bottom part provided with an infrared light filter that is disposed to correspond in position with the infrared light receiver.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:
Referring to
Referring to
The driving unit 13 includes a fixing disc 131, a rotary disc 132, and a conductor unit 133. The fixing disc 131 has the first processing unit 11 mounted thereon. The rotary disc 132 has the directional transmitting unit 12 mounted thereon. The rotary disc 132 is coupled rotatably to the fixing disc 131 such that the rotary disc 132 and the directional transmitting unit 12 are co-rotatable relative to the first processing unit 11. The conductor unit 133 is coupled between the fixing disc 131 and the rotary disc 132. In particular, the first processing unit 11 makes electrical connection with one surface of the conductor unit 133 that faces the fixing disc 131, while the directional transmitting unit 12 makes electrical connection with the other surface of the conductor unit 133 that faces the rotary disc 132. As a result, electrical connection between the directional transmitting unit 12 and the first processing unit 11 is established via the conductor unit 133 and can be maintained even when the rotary disc 132 is rotated relative to the fixing disc 131.
The signal terminal 14 is coupled to the first processing unit 11 and extends out of the fixing disc 131 so as to be adapted for plugging into a dedicated socket on an armrest of a passenger seat in the vehicle cabin for establishing electrical connection between the first processing unit 11 and a signal source, e.g., an audio signal source.
The first processing unit 11 processes signals received from the signal source, and provides processed signals to the directional transmitting unit 12, which is responsible for wirelessly transmitting the same.
It should be noted herein that the directional transmitting unit 12 does not transmit signals omni-directionally, but is operable so as to wirelessly transmit signals from the first processing unit 11 along a primary signal transmitting direction. The directional transmitting unit 12 thus includes a directional or slanting directional radiating component (to be described in greater detail in the succeeding paragraphs).
Referring to
The receiving unit 22 receives signals wirelessly transmitted by the directional transmitting unit 12 of the transmitting device 1.
The second processing unit 21 is coupled to the receiving unit 22 for processing signals received therefrom.
The speaker unit 23 is connected to the second processing unit 21 for receiving and reproducing the signals processed by the second processing unit 21.
In view of the directional characteristics of signals transmitted by the directional transmitting unit 12, interference with signals transmitted by the transmitting device 1 on an adjacent passenger seat can be avoided. Moreover, by virtue of the driving unit 13, the primary signal transmitting direction of the directional transmitting unit 12 is adjustable by the passenger to ensure optimum signal reception by the receiving device 2.
In this embodiment, the directional transmitting unit 12 includes three infrared light emitters 121 (as best shown in
Each of the infrared light emitters 121 transmits infrared light with a limited beam width (e.g., 60 degrees) along a primary transmitting direction. In this embodiment, each of the infrared light emitters 121 transmits light with a wavelength of 850 nm. The three infrared light emitters 121 are connected in series and are so disposed such that the primary transmitting directions of adjacent ones of the infrared light emitters 121 are spaced apart by an angle of approximately 20 degrees, such that the radiation patterns of each adjacent pair of the infrared light emitters 121 overlap, and such that the infrared light emitters 121 cooperatively impart the directional transmitting unit 12 with a collective radiation pattern having a ±30° half-power beam width, as best shown in
Referring to
Referring to
To ensure that a passenger using the system of this invention is able to hear announcements made by flight personnel, the second processing unit 21 of this embodiment is shown to further include an acoustic transducer 202 for sound pickup (for instance, announcements made by flight personnel), an audio preamplifier 201 connected to the acoustic transducer 202 and the audio power amplifier 215 and operable so as to amplify sounds picked up by the acoustic transducer 202, and a mute controller unit 203 that is connected to the audio preamplifier 201 and the FM stereo demodulator 214, and that is selectively operable via a switch so as to suppress output of the left and right channel signals by the FM stereo demodulator 214 and so as to simultaneously enable output of amplified sounds from the audio preamplifier 201 to the audio power amplifier 215, thereby enabling broadcast of announcements made by flight personnel.
Moreover, in the prior art, listeners usually turn up the volume to drown out background noise, which may cause ear injury. In order to avoid the need for listeners to turn up the volume for the sake of drowning out background noise, the second processing unit 21 further includes another acoustic transducer 204 for pickup of background sound and disposed together with the speaker unit 23 in a sealed compartment, and a feedback filter 205 connected to the acoustic transducer 204 and the audio power amplifier 215 and operable to filter out a noise component from output of the acoustic transducer 204 and to generate a noise compensating signal that corresponds to the noise component (i.e., having a same magnitude but opposite polarity as the noise component) and that is provided to the audio power amplifier 215 to counteract effect of background noise.
Referring to
Since infrared light transmission is employed in the system of this embodiment, the system can comply with the EMI restrictions imposed by the FAA.
However, it should be noted herein that the mode of transmission suitable for the present invention should not be limited to infrared light transmission. The passenger seats of most airplanes are currently installed with display devices that also generate a certain amount of electromagnetic interference. Since the presence of these display devices posed no safety concerns, there is a possibility that the FAA may relax its EMI restrictions in the future.
Therefore, instead of infrared light transmission, the mode of transmission between the transmitting and receiving devices of the system of this invention may be based on a Bluetooth protocol in other embodiments of this invention. Compared to commercially available Bluetooth devices, the transmitting power is considerably reduced in the system of this invention to comply with future FAA restrictions.
Moreover, a conventional Bluetooth device uses an omni-directional antenna for signal transmission in all directions with a transmission range of at least 10 meters. In contrast, the directional transmitting unit of the transmitting device of the system of this invention, which is based on a Bluetooth protocol, uses a directional or slanting directional antenna for signal transmission along a primary signal transmitting direction so as to minimize undesired electromagnetic interference. In addition, the transmitting power is reduced to result in a transmission range that is not more than two meters, which is sufficient for a passenger seated in a vehicle cabin. Furthermore, by virtue of the driving unit of the transmitting device, the primary signal transmitting direction of the directional transmitting unit is adjustable by the passenger to ensure optimum signal reception by the receiving device.
The first and second processing units of the system of this invention, which is based on a Bluetooth protocol, can be realized using conventional CSR BlueCore 3 chip sets. Since the feature of this invention does not reside in the implementation of the first and second processing units in the Bluetooth-based system, further details of the same are omitted herein for the sake of brevity.
The mode of transmission between the transmitting and receiving devices of the system of this invention may be based on other wireless radio-frequency communications schemes, such as 802.11a/b/g, in further embodiments of this invention. Compared to commercially available wireless radio-frequency devices, the transmitting power is considerably reduced in the system of this invention to comply with safety restrictions.
Moreover, a conventional 802.11a/b/g device uses an omni-directional antenna for signal transmission in all directions with a transmission range of over 100 meters. In contrast, the directional transmitting unit of the transmitting device of the system of this invention, which is based on 802.11a/b/g, uses a directional or slanting directional antenna for signal transmission along a primary signal transmitting direction so as to minimize undesired electromagnetic interference. In addition, the transmitting power is reduced to result in a transmission range that is not more than two meters, which is sufficient for a passenger seated in a vehicle cabin. Furthermore, by virtue of the driving unit of the transmitting device, the primary signal transmitting direction of the directional transmitting unit is adjustable by the passenger to ensure optimum signal reception by the receiving device.
The first and second processing units of the system of this invention, which is based on 802.11a/b/g, can be realized using conventional NRF 24Z1 (wireless audio streamer) chip sets. Since the feature of this invention does not reside in the implementation of the first and second processing units in the 802.11a/b/g-based system, further details of the same are omitted herein for the sake of brevity.
While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
