JPH07255043A - Information providing device - Google Patents

Abstract

PURPOSE:To increase usable transmission channels by a multiple in proportion to a ratio of digital compression. CONSTITUTION:A video supply part 10A multiplexes compressed digital video signal of four channels by time division and RF modulates to output a signal c1 which has its band limited to 6MHz. An analog video supply part 11 outputs a signal c21 which has its band limited to 6MHz. A digital sound supply part 12 multiplexes digital audio signals of 32 channels by time division and RF modulates to output a signal c22 which has its band limited to 6MHz. The signal c1-c22 are mixed and sent to an information control part 15A by a coaxial cable 14. Assuming that only the digital video supply parts 10A, 10B... are used as video information sources, up to 84 channels (=(126MHz of the video band of the coaxial cable 14/6MHz)X4ch) are obtained and greatly increased as compared with conventional 20 channels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information providing apparatus for supplying AV information on an aircraft, and more particularly to an information providing apparatus capable of easily increasing the number of channels of video information.

[0002]

BACKGROUND OF THE INVENTION Passenger aircraft currently in use are
An audio tuner is built into each armrest of each seat, and an information providing device capable of listening to audio information such as music by connecting headphones to this is usually equipped. In addition, recently I have a video monitor,
An increasing number of aircraft are equipped with information providing devices capable of viewing video information.

[0003]

In order to increase the number of passengers in passenger aircraft, it is necessary to reduce the weight and volume of not only the fuselage but also various equipment and devices mounted therein. . Here, regarding the information providing device, the volume and weight of the cable that transmits information is large. This is because a monitor and headphones are attached to a large number of seats, respectively, and the audio information and the video information output from the central audio information and video information supply device are transmitted to all monitors through a control unit or a receiving unit in the middle. In addition, since the cable is supplied to the headphones, the length of the cable connecting these becomes enormous. Therefore, in the information providing device, reducing the weight of the cable is effective in reducing the weight of the entire device.

On the other hand, in an aircraft, there are a plurality of seats, for example, 3 seats.
A seat constitutes one box, and a long groove-shaped rail is formed on the floor surface to fix the legs of the block. The cable of the information providing device is laid in this rail. The entrance of the rail is covered with a cover that shields the inside. Since the cross-sectional area of the rail is relatively small, the fact is that only a small number of small-diameter cables can pass through.

For this reason, the diameter of the cable that can be used in the information providing apparatus is limited, and in the conventional information providing apparatus, the video information for one TV signal channel, that is, the band limited to 6 MHz is transmitted as an analog signal. However, it was limited to providing video information of about 20 channels at most. Therefore, there is a problem that the use range of the information providing device is limited as described below.

[0006] For example, since a video tape of a movie is sold on-board, even if an information providing apparatus tries to stream it for previewing, only 20 channels at maximum, that is, 20 movies can be streamed. This is not enough to satisfy the tastes of many passengers, and in-flight sales of such videotapes are less effective in the end. As described above, the conventional information providing apparatus has a problem in that the number of channels that can be provided is small, and thus the types of products that can be adopted for in-flight sales are limited.

There is also a case where the video is transmitted as digital information in the base band. In this case, the transmission rate is changed when the channel is added, that is,
The circuit of the device needs to be changed, and the cost becomes very high, so that there is a problem that it is difficult to implement in practice. Furthermore, in the case where the image output from the TV camera or the TV tuner is provided in real time by this information providing device, an encoder for digitally compressing the image is required. This encoder has a problem that it is very large in scale and causes an increase in weight and cost.

Therefore, the present invention solves the above-mentioned problems and proposes an information providing apparatus in which the number of video channels that can be provided is large and the number of channels can be easily increased.

[0009]

In order to solve the above problems, in the invention according to claim 1, a digital video signal output means for outputting a plurality of compressed digital video signals, and a plurality of compressed digital video signals. Multiplex circuit for time-division multiplexing video signals, digital video signal modulation circuit for modulating output signal of multiplex circuit, output signal of digital video signal modulation circuit and other input signals are supplied, and output of digital video signal modulation circuit A frequency multiplexing circuit that frequency-multiplexes signals and other input signals, a tuner that receives and demodulates the output signal of the frequency multiplexing circuit, and that selects a signal of a specific frequency, and a plurality of time-division-multiplexed tuner output signals. A video signal selection circuit for selecting one compressed digital video signal from among the compressed digital video signals of A decompression circuit for decompressing output signals of 択回 path, is characterized in that a display means for displaying an image by receiving the output signal of the expanding circuit.

According to another aspect of the present invention, there are provided a digital video signal output means for outputting a plurality of compressed digital video signals, a multiplexing circuit for time-division multiplexing the plurality of compressed digital video signals, and a multiplexing circuit. An analog video signal supply including a digital video supply unit including a digital video signal modulation circuit that modulates an output signal, an analog video signal output unit that outputs an analog video signal, and an analog video signal modulation circuit that modulates the analog video signal. And a voice signal output means for outputting a plurality of voice signals,
An audio signal multiplexing circuit for time-division multiplexing a plurality of audio signals,
Frequency-multiplexing the respective output signals from the audio signal supply section, which comprises an audio signal modulating means for modulating the output signal of the audio signal multiplexing circuit, and the digital video signal supply section, the analog video signal supply section and the audio signal supply section. And a frequency multiplexing circuit.

According to a seventh aspect of the present invention, there are provided a digital video signal output means for outputting a plurality of compressed digital video signals, a multiplexing circuit for time-division multiplexing a plurality of compressed digital video signals, and a multiplexing circuit. An analog video signal supply including a digital video supply unit including a digital video signal modulation circuit that modulates an output signal, an analog video signal output unit that outputs an analog video signal, and an analog video signal modulation circuit that modulates the analog video signal. And a voice signal output means for outputting a plurality of voice signals,
An audio signal multiplexing circuit for time-division multiplexing a plurality of audio signals,
Frequency-multiplexing the respective output signals from the audio signal supply section, which comprises an audio signal modulating means for modulating the output signal of the audio signal multiplexing circuit, and the digital video signal supply section, the analog video signal supply section and the audio signal supply section. One of a frequency multiplexing circuit, a tuner for receiving and demodulating an output signal of the frequency multiplexing circuit and selecting a signal of a specific frequency, and one of a plurality of compressed digital video signals time-division multiplexed in the output signal of the tuner. A video signal selection circuit for selecting two compressed digital video signals, an audio signal selection circuit for selecting one audio image signal among a plurality of time-division multiplexed audio signals in the output signal of the tuner, and a video signal A decompression circuit for decompressing the output signal of the selection circuit, a decoder for decoding the analog video signal in the output signal of the tuner, Is characterized in further comprising a display means for receiving receive either of the long circuit and the decoder output signal.

[0012]

As shown in FIG. 1, the digital video supply unit 10
In A to 10T, for example, compressed digital video signals for four channels are time-division multiplexed and this is 6M.
RF-modulated signals c1 to c20 which are band-limited to Hz
Is output. 6 MH from the analog video supply unit 11
An RF-modulated signal c21 that is band-limited to z is output. Further, in the digital voice supply unit 12, for example, 3
Two channels of digital audio signals are time-division multiplexed, and the signals are band-limited to 6 MHz and RF-modulated signal c22 is output.

These signals c1 to c22 are mixed by the mixing circuit 13
Are mixed by the coaxial cable 14, and each information control unit 15A,
15B ... The transmission band of the coaxial cable 14 is 300 MHz, and in this example, as shown in FIG. 5, audio information is in the range of 138 to 162 MHz and video information is 16 MHz.
Used in the range of 2 to 288 MHz.

Therefore, the maximum number of channels that can be provided as voice information is 128 channels (= (24 MHz / 6M
Hz) × 32 channels). Now, when only the digital video supply units 10A, 10B ... Are used as video information sources, the maximum number of channels that can be provided is 84 channels (= (126 MHz / 6 MHz) × 4 channels), which is the maximum that can be provided by the conventional method. The number of channels is significantly increased compared to 20 channels.

In the information control units 15A, 15B ..., One of the signals c1 to c20 or the signal c22 is selected and demodulated by the tuners 20 and 21. Furthermore, the separator 2
2, 23 separates the digital video signals a1 to a4 (FIG. 2) or the digital audio signals h1 to h32 (FIG. 4) before multiplexing, and one of them is selected and expanded by the expanders 24 and 25. It is converted into video signals p1 to p20 or analog audio signals q1 to q32. When the signal c21 is selected by the tuner 20, this is decoded by the decoder 27 and converted into the video signal p21. Then, the selected video signals p1 to p21 are displayed on the liquid crystal monitors 28A to 28C. In addition, the selected analog audio signals q1 to q
32 is supplied to the headphones 29A to 29C and converted into sound.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the information providing apparatus according to the present invention applied to an aircraft will be described in detail with reference to the drawings.

FIG. 1 shows the configuration of an AV information providing apparatus 1 for an aircraft to which the present invention is applied. This AV information providing device 1
Is a plurality, in this example, 20 digital video supply units 1
0A to 10T, one analog video supply unit 11, 1
And a digital audio supply unit 12. These form a transmitting device which is a side for transmitting a digital video signal, an analog video signal and a digital audio signal.

In the digital video supply unit 10A,
A disc 3 for reproducing a digital signal as shown in FIG.
A plurality of 0A to 30D, four in this example, are provided, and each disk 30A to 30D is, for example, 1.5M in MPEG or the like.
Video signals a1 to a4 digitally compressed to bps are recorded.

Then, these video signals a1 to a4 are reproduced and supplied to the time division multiplexing circuit 31, where they are time division multiplexed and a 6 Mbps digital signal b1 is output. This digital signal b1 is supplied to the RF (TV) modulator 3
The signal is modulated into a signal c1 by 2 and output. In this example, the signal c1 is band-limited to 6 MHz, which is the same as one channel of the TV signal. That is, here, the digital video signal a1 for four channels is supplied from one digital video supply unit 10A.
The signal c1 including -a4 is output.

Similarly, another digital video supply unit 10
4 channels of digital video signal a from B to 10T
Signals c2 to c2 including 5 to a8, a9 to a12 ...
0 is output. Therefore, a total of 80 (= 20 × 4) channels of digital video are supplied from these digital video supply units 10A to 10T. The carrier frequencies of the signals c1 to c20 are different from each other f
1 to f20, and each carrier frequency width is band-limited to 6 MHz for one TV channel.

In the above example, the four types of video signals are compressed into 1.5 Mbps digital video signals a1 to a4 from the relation that the output of the RF modulator 32 is band-limited to 6 MHz, and the four video signals are compressed. Although the case of recording on 30A to 30D has been described, if the video signal to be recorded on one disk 30A is digitally compressed to 1.0 Mbps, the number of channels n that can be added to the signal c1 is n =
6 Mbps / 1.0 Mbps = 6.

That is, each digital image supply unit 10A
6 at 10T using 6 disks 30A-30F
It becomes possible to supply images for channels. Therefore, it is possible to supply video for 120 (= 20 × 6) channels as a whole. In this way, the digital video signal a recorded on each of the disks 30A, 30B, ...
It is possible to easily change the number of video channels supplied from each of the digital video supply units 10A, 10B ... By changing the compression rates of 1, a2.

In the analog video supply section 11, as shown in FIG. 3, analog video signals d1 and d2 output from, for example, the TV camera 40 or the TV tuner 41.
Is RF-modulated by the RF modulator 42 and the signal c21 is output. The carrier frequency width of the signal c21 is also the above-mentioned signals c1 to c1.
As with c20, the band is limited to 6 MHz. Signal c
The carrier frequency of 21 is f21.

As shown in FIG. 4, the digital audio supply unit 12 is provided with a plurality of audio reproducing devices such as a CD player, 32 in this example, and the analog reproducing devices 51 to 82 are different from each other. Audio signal g1
~ G32 is output. Then, these analog audio signals g1 to g32 are converted into 12 by the compression circuits 91 to 122, respectively.
The signals are compressed into 8 Kbps digital signals h1 to h32 and supplied to the time division multiplexing circuit 130. Time division multiplexing circuit 1
At 30, each of the digital signals h1 to h32 is time-division multiplexed, and a 6 Mbps digital signal j is output from this. The digital signal j is modulated by the RF modulation circuit 131 and the signal c22 is output. The carrier frequency width of the signal c22 is band-limited to 6 MHz, and its carrier frequency is f22.

Now, referring to FIG. 1, the signals c1 to c output from the digital video supply units 10A to 10T, the analog video supply unit 11 and the digital audio supply unit 12 described above.
22 is mixed (frequency-multiplexed) by the mixer 13, and this is supplied to the plurality of information control units 15A, 15B ... Through the coaxial cable 14 used as a transmission line. That is, the coaxial cables 14 transmit signals c1 to c22 having carrier frequencies f1 to f22, each of which has a band of 6 MHz. In this example, a coaxial cable 14 having a transmission bandwidth of 300 MHz is used as shown in FIG.
This is about the same transmission band as a general TV signal, and it is possible to transmit frequencies higher than this, but this causes a large loss and requires an amplifier with a higher amplification factor. As it occurs, here 300 MH
Limited to z position.

The signal c22 for audio information transmission is set to the carrier frequency f22 between 138 MHz and 162 MHz as shown in FIG. 5, and the signals c1 to c for video information transmission are set.
21 is set to carrier frequencies f1 to f21 between 162 MHz and 288 MHz.

Since there is a margin of 18 MHz for voice, the digital voice supply unit 12 is further divided into three.
It is possible to provide individual pieces, that is, 96 channels, and provide a total of 128 channels of audio information. In this case, the bandwidths of the carrier frequencies f22 to f25 of the signals c22 to c25 output from the digital audio supply units 12 may be limited to 6 MHz and different frequencies may be set.

In the above-described embodiment, the number of digital image supply units 10A, 10B, ... Is 20 and the number of analog image supply units 11 is one. However, the number of analog image supply units 11 is increased, and digital image supply is increased accordingly. Parts 10A, 10B
・ ・ Can be reduced. That is, a total of 21 video supply units may be used.

Now, the information control units 15A and 15B shown in FIG.
... are provided at a rate of one in a plurality of seats of one seat of the aircraft, in this example, three seats. That is, one information control unit 15A has three seats 16
It manages A to 16C. Then, the signals c1 to c22 output from the mixer 13 are input to the respective information control units 15A, 15B, ... Through the coaxial cable 14.

For example, the information controller 15A includes a distributor 17
And the number of seats equal to the number of seats 18A to 18C (receiver 18
Only the configuration A is shown) and a CPU 19 is provided.
The signals c1 to c22 input to the information controller 15A are distributed by the distributor 17 and supplied to the receivers 18A to 18C. RF signal c1 input to each of the receivers 18A to 18C
The c22 is supplied to the video tuner 20 and the audio tuner 21. In each of the tuners 20 and 21, first, signals c1 to
c22 is demodulated into the digital signals b1 to b20, the analog video signals d1 and d2, and the digital signal j.

On the other hand, the CPU 19 has the seats 16A to 16
From the operation section 33A provided on the armrest section of C,
Select signals k1 to k3 for selecting a specific audio channel or a specific video channel are supplied. As a result, the CPU 19 sends the control signals m1 to m3 to control the tuners 20 and 21, respectively.
A signal having a specific carrier frequency fn is selected from the signals b1 to b20, d1 to d2, and j demodulated in (1) and output. That is, when the video channel is specified by the control signals m1 to m3, the video tuner 20 outputs one of the digital signals b1 to b20 and the analog video signals d1 and d2, and the audio channel is specified. A digital signal j is output from the audio tuner 21.

When, for example, the digital signal b1 is selected by the video tuner 20, the digital signal b1 is supplied to the video separator 22 and the digital video signal a before time division multiplexing is supplied.
1 to a4 are separated. Furthermore, any of the digital video signals a1 to a4 separated by the control of the CPU 19,
For example, the digital video signal a1 is selected. The digital video signal a1 selected here is the video expander 24.
Is supplied to the terminal b of the changeover switch 26 and converted into the video signal p1.

Similarly, when the other digital signals b2 to b20 are selected by the video tuner 20, the same processing as described above is performed and the expander 24 outputs the video signals p2 to p20.
Is output, and this is supplied to the terminal b of the changeover switch 26. When an analog video signal d is output from the video tuner 20, it is decoded by the decoder 27 and converted into a video signal p21, which is supplied to the terminal a of the changeover switch 26.

The changeover switch 26 is controlled by the changeover signal t1 output from the CPU 19 in response to the selection signal k1 and is changed over to one of the terminals a and b. As a result, any one of the video signals p1 to p21 is transmitted to the amplifier 6
It is supplied to, for example, the liquid crystal monitor 28A via 0, and the image of the designated channel is displayed.

The digital signal j output from the audio tuner 21 is supplied to the audio separator 23, where the digital audio signals h1 to h1 before being time-division multiplexed.
It is separated into h32. Further, of these digital audio signals h1 to h32, for example, the digital audio signal h1 is selected and expanded by the audio expander 25 to be converted into the analog audio signal q1. Similarly, when other digital audio signals h2 to h32 are selected by the separator 23,
The expander 25 converts the analog audio signals q2 to q32. Then, these analog audio signals q1 to q32 are supplied to, for example, the headphones 29A and converted into sound.

The same processing as described above is performed in the other receivers 18B and 18C, and the liquid crystal monitor 2 of the seats 16B and 16C is also used.
8B, 28C or the headphones 29B, 29C can view the selected video channel or audio channel. Further, the other information control units 15B, 15C, ... Perform the same processing as that of the above-mentioned information control unit 15A, and it becomes possible to view the separately selected video or audio in all seats in the aircraft. The information control units 15A, 15B, ... Can be added in any number without changing the circuits of other parts as long as the quality of the RF signal is ensured.

As described above, in the AV information providing device 1, different media, digital video signals in this example,
Since the transmission band of the analog video signal and the digital audio signal is limited to 6 MHz, the digital signal and the analog signal can coexist. Therefore, the number of channels can be easily increased without changing the circuit even for a signal that must be transmitted in real time, such as the output of the TV camera 40.

Further, the digital video supply units 10A, 10
In B ..., video signals are digitally compressed by MPEG or the like and recorded on the disks 30A, 30B. By changing the compression rate of the digital video signal, the number of channels of the video signal from each of the digital video supply units 10A, 10B, ... Can be changed without changing the coaxial cable 14. In this example, the digital video signal a1
Since ~ a4 is compressed to 1.5 Mbps, it is possible to provide 4 (= 6 Mbps / 1.5 Mbps) times as many channels as the conventional one.

In the above embodiment, the case where all of the digital video supply units 10A to 10T, the analog video supply unit 11, and the digital audio supply unit 12 are provided has been described, but these are adjusted according to the budget and other circumstances. It is also possible to provide them in appropriate combination. Furthermore, the use of the coaxial cable 14 having a wide transmission band makes it possible to provide more channels.

[0040]

As described above, the present invention time-division multiplexes a plurality of digitally compressed video signals, and
The bandwidth of the modulation frequency of audio information and analog video signals, for example, 6M which is the same as the bandwidth of the carrier frequency of TV channels
It is designed to be transmitted after being modulated to Hz.

Therefore, according to the present invention, it is possible to increase the number of video channels by a multiple corresponding to the digital compression ratio, as compared with the case where only analog video signals are RF-modulated and transmitted. In this case, the number of channels can be increased without changing the circuit of each unit. Further, the digital video signal can be made to coexist with the analog video signal, and it is not necessary to compress the video signal that must be broadcast in real time such as a TV camera, so that the configuration is simplified. Furthermore, when voice information is provided, it is possible to transmit it with high quality.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an AV information providing apparatus 1 of an aircraft to which an information providing apparatus according to the present invention is applied.

FIG. 2 is a configuration diagram of digital image supply units 10A to 10T.

FIG. 3 is a configuration diagram of an analog video supply unit 11.

FIG. 4 is a configuration diagram of a digital audio supply unit 12.

FIG. 5 is a transmission band of the coaxial cable 14 and respective signals c1 to c
It is a figure which shows the carrier wave frequencies f1-f22 of 22.

[Description of Reference Signs] 1 AV information providing device 10A to 10T Digital video supply unit 11 Analog video supply unit 12 Digital audio supply unit 13 Mixing circuit 14 Coaxial cable 19 CPU 20 Video tuner 21 Audio tuner 22, 23 Separator 24, 25 Stretcher 28A-28C Liquid crystal monitor 29A-29C Headphones 30A-30C Disk 31,130 Time division multiplexing circuit 32,42,131 RF modulator

Claims (7)

[Claims] 1. A digital video signal output means for outputting a plurality of compressed digital video signals, a multiplex circuit for time-division multiplexing the plurality of compressed digital video signals, and an output signal of the multiplex circuit. A digital video signal modulation circuit, a frequency multiplexing circuit that is supplied with an output signal and other input signals of the digital video signal modulation circuit, and frequency-multiplexes the output signal of the digital video signal modulation circuit and the other input signal, A tuner for receiving and demodulating the output signal of the frequency multiplexing circuit and selecting a signal of a specific frequency, and one of the plurality of compressed digital video signals time-division multiplexed in the output signal of the tuner. Video signal selection circuit for selecting the digital video signal, and expansion for expanding the output signal of the selection circuit An information providing apparatus comprising: a circuit; and a display unit that receives an output signal of the decompression circuit and displays an image. 2. An analog video signal output means for outputting an analog video signal, and an analog video signal for modulating the analog video signal and supplying the analog video signal modulated as the other input signal to the frequency multiplexing circuit. 2. The information providing apparatus according to claim 1, further comprising a modulation circuit and a decoder that receives and decodes an analog signal in the output signal of the tuner, and the output of the decoder is supplied to the display means. 3. The information providing apparatus according to claim 2, wherein each of the digital video signal modulation circuit and the analog video signal modulation circuit is an RF modulation circuit that modulates with a carrier frequency width of 6 MHz. 4. An audio signal output means for outputting a plurality of audio signals, an audio signal multiplexing circuit for time-division multiplexing the plurality of audio signals, an output signal of the audio signal multiplexing circuit, and a modulated signal. An audio signal modulating means for supplying as the other input signal of the frequency multiplexing circuit, and an audio signal selecting circuit for selecting one of the plurality of audio signals time-division multiplexed in the output signal of the tuner. The information providing apparatus according to claim 1, further comprising: 5. The information providing apparatus according to claim 4, further comprising an audio signal compression circuit for compressing a plurality of audio signals from said audio signal output means, and an expansion circuit for expanding an output signal of said audio signal selection circuit. 6. A digital video signal output means for outputting a plurality of compressed digital video signals, a multiplexing circuit for time division multiplexing the plurality of compressed digital video signals, and an output signal of the multiplexing circuit. A digital video signal supplying section including a digital video signal modulating circuit; an analog video signal outputting means for outputting an analog video signal; and an analog video signal supplying section including an analog video signal modulating circuit for modulating the analog video signal. An audio signal output means for outputting the audio signal, an audio signal multiplexing circuit for time-division multiplexing the plurality of audio signals, and an audio signal supplying means for modulating the output signal of the audio signal multiplexing circuit. From the digital video signal supply section, the analog video signal supply section, and the audio signal supply section. Information transmitting apparatus characterized in that it comprises a frequency multiplexing circuit for frequency multiplexing of the output signal. 7. A digital video signal output means for outputting a plurality of compressed digital video signals, a multiplexing circuit for time division multiplexing the plurality of compressed digital video signals, and an output signal of the multiplexing circuit. A digital video signal supplying section including a digital video signal modulating circuit; an analog video signal outputting means for outputting an analog video signal; and an analog video signal supplying section including an analog video signal modulating circuit for modulating the analog video signal. An audio signal output means for outputting the audio signal, an audio signal multiplexing circuit for time-division multiplexing the plurality of audio signals, and an audio signal supplying means for modulating the output signal of the audio signal multiplexing circuit. From the digital video signal supply section, the analog video signal supply section, and the audio signal supply section. A frequency multiplexing circuit for frequency-multiplexing the output signal of, a tuner for receiving and demodulating the output signal of the frequency multiplexing circuit and selecting a signal of a specific frequency, and a plurality of time-division multiplexed signals in the output signal of the tuner. A video signal selection circuit that selects one compressed digital video signal from the compressed digital video signals, and one audio image signal of a plurality of audio signals time-division multiplexed in the output signal of the tuner. Any of an audio signal selection circuit for selecting, an expansion circuit for expanding the output signal of the video signal selection circuit, a decoder for decoding an analog video signal in the output signal of the tuner, and an output signal of the expansion circuit and the decoder. An information providing apparatus comprising: a display unit for receiving and displaying the information.