JP2000050309A - Multiplex transmitter and information display device for mobile body using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a transmitter compact by improving a multiplexing, modulating and demodulating method for transmission data such as a video/audio signal. SOLUTION: The transmitter is provided with a modulation reference carrier generator section 3 that generates a modulation reference carrier, a 1st frequency modulation section 4 that applies frequency modulation to a frequency signal of the modulation reference carrier in response to a video signal on which a synchronizing signal is superimposed, 1st frequency divider sections 6, 9 that apply frequency division to the modulation reference carrier at a prescribed ratio, and 2nd frequency modulation sections 7, 10 that apply frequency modulation to the frequency signal of the modulation carrier frequency- divided at a prescribed ratio depending on the video signal on which the control signal is superimposed, and mixes the data with an audio signal and transmits the data as a base band signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission apparatus for multiplexing and transmitting a video signal, an audio signal for guidance, a synchronization signal for display, and a control signal for controlling a display monitor, which are calculated by a processing device body. The present invention relates to a mobile information display device that provides various types of information including map information using a navigation function to occupants of a mobile such as a vehicle, an aircraft, and a ship.

[0002]

2. Description of the Related Art In general, in a mobile information display device in which a display data calculation section and a calculation result display section are separated, data transmission from the calculation section to the display section is separated into three primary colors of red, green and blue. A signal line is allocated to each of the video luminance signal, a synchronization signal for display timing, a control signal for determining the operation of the display unit, and an audio signal for performing route guidance by voice, and transmission is performed.

[0003] Therefore, a plurality of signal lines for connection are required, and the bundle diameter of the signal lines becomes large. Therefore, when the display device for a mobile object is installed, not only restrictions on wiring layout, installation space, and the like are caused, but also the appearance of the living space is impaired. In addition, since baseband transmission is performed, signal degradation in the transmission signal line and inter-signal interference also occur,
In particular, the image quality also deteriorates.

Conventionally, a multiplex transmission apparatus as shown in FIGS. 6 and 7 has been proposed to solve such a problem. FIGS. 6 and 7 are a circuit diagram and a band plan of a multiplex transmission apparatus disclosed in Japanese Patent Application Laid-Open No. 8-163595. The transmission side has four FM modulators, one AM modulator, and FSK.
One demodulator is arranged. On the receiving side, four FM demodulators for demodulating the multiplex transmission signal from the transmitting side
One demodulator and one FSK modulator are arranged. FIG. 2 shows the band plan, which has a total of four signal peaks, three for video, one for audio, and one for remote control.

The configuration and operation of a conventional multiplex transmission apparatus will be described with reference to FIG. The G signal and the synchronizing signal are applied to the FM modulator 3
1, R and B signals are FM modulators 32 and 33, and audio signals are F
An M modulator 34 modulates a control signal for controlling the display panel with an AM modulator / multiplexer 35, and modulates the control signal.
The signal is multiplexed with the signal from the M modulator 34. These carriers having different frequencies are mixed by a mixer 36 and transmitted to a display panel unit via a signal line 37. FM demodulation unit 38
, The G signal and the synchronization signal, and the FM demodulation units 39 and 40
The signal is demodulated and an image is displayed on the display panel 45. Further, the conventional multiplex transmission apparatus is configured so that the audio signal is demodulated by the sync separation unit 42 and further demodulated into a stereo signal, and then the audio is output from the speaker 30.

[0006]

Since the conventional multiplex transmission apparatus is configured as described above, the number of carriers is increased, and a plurality of carrier generators must be provided on both the transmission side and the demodulation side. In addition, there are also problems that the circuit configuration is complicated due to many components such as a modulator and a demodulator, and the manufacturing cost is increased. Furthermore, since each modulation section and demodulation section are configured independently of each other, there are many adjustment points in the production and adjustment of the apparatus, and there is a problem that the production efficiency is not good.

The present invention has been made to solve such a problem, and a first object of the present invention is to reduce the number of signals to be modulated and to multiplex transmission data such as video and audio signals. An object of the present invention is to provide a compact and inexpensive multiplex transmission apparatus by reducing the number of modulators, demodulators, and carrier generators to simplify the circuit configuration by improving the modulation and demodulation method.

A second object of the present invention is to provide a multiplexing system for displaying a high-quality image by preventing signal deterioration and inter-signal interference in a signal line connecting a transmitting side signal processing unit and a receiving side signal processing unit. A transmission device is provided.

A third object of the present invention is to reduce the number of signal lines for transmitting a video / audio multiplexed signal from the transmission-side signal processing unit to the reception-side signal processing unit, thereby increasing the degree of freedom in wiring layout. A multiplex transmission device is provided.

[0010] A fourth object of the present invention is to provide a multiplex transmission apparatus which solves the above problems and can be freely installed even in a limited space of a mobile body such as an automobile, an aircraft, a ship or a railway. An object of the present invention is to provide a mobile information display device.

[0011]

A multiplex transmission apparatus according to the present invention transmits a video / audio multiplex signal generated by multiplexing an audio signal and a video signal containing three primary color signals of red, green and blue. A signal processing unit for receiving the video / audio multiplexed signal transmitted via a signal line connected to the transmission side signal processing unit, separating the video signal and the audio signal, and performing video display. A multiplex transmission apparatus having a receiving-side signal processing unit for outputting data, wherein the transmitting-side signal processing unit includes a modulation reference carrier generator for generating a modulation reference carrier having a predetermined frequency. A first signal for superimposing a synchronization signal for video display on one color signal and outputting a first modulation wave generated by frequency-modulating the modulation reference carrier in accordance with the color signal on which the synchronization signal is superimposed. A wave number modulation unit, a transmission-side frequency divider that divides a frequency signal of the modulation reference carrier and outputs a modulated carrier having a different frequency, and a control signal that controls video display to at least one color signal on which a synchronization signal is not superimposed. A second frequency modulator that frequency-modulates the modulated carrier and outputs a second modulated wave according to the color signal on which the control signal is superimposed, wherein the first and second frequency modulators are A mixer for mixing the output first and second modulated waves with an audio signal to generate a video / audio multiplexed signal, for transmitting the video / audio multiplexed signal in baseband, and the reception-side signal processing unit The unit demodulates the frequency of the first modulated wave separated from the received video / audio multiplexed signal, and detects a frequency error between the frequency of the modulated reference carrier and the frequency of the first modulated wave. A wave number demodulation unit, a demodulation reference carrier generator that generates a demodulation reference carrier corrected for the frequency error detected by the first frequency demodulation unit, and a transmission frequency divider that divides the modulation reference carrier by the same ratio. A receiving-side divider that divides a demodulation reference carrier and outputs a demodulated carrier having a different frequency, a second frequency demodulator that frequency-demodulates the second modulated wave according to the demodulated carrier; It outputs a signal and a voice signal.

Further, a multiplex transmission apparatus according to the present invention comprises:
The reception-side signal processing unit includes a first frequency demodulation unit that detects an amplitude shift of a synchronization signal included in a first modulated wave.

Further, the multiplex transmission apparatus according to the present invention comprises:
A transmission side signal processing unit including a control signal superimposing unit for superimposing a control signal as a serial signal on a video signal is provided.

Further, the information display device for a mobile object according to the present invention is a transmitting-side signal for transmitting a video / audio multiplexed signal generated by multiplexing an audio signal and a video signal containing red, green and blue primary color signals. A multiplex transmission device having a processing unit and a receiving-side signal processing unit for receiving the video / audio multiplexed signal, separating the video signal and the audio signal, and outputting data for performing video display, The transmission-side signal processing unit unit superimposes a synchronization signal for video display on one of the three primary color signals, a modulation reference carrier generator that generates a modulation reference carrier of a predetermined frequency. A first frequency modulator that outputs a first modulated wave generated by frequency-modulating the modulated reference carrier in accordance with the superimposed color signal; A transmission-side frequency divider that outputs a carrier, a control signal for controlling video display is superimposed as a serial signal on at least one color signal on which no synchronization signal is superimposed, and the modulated carrier is frequency-modulated according to the color signal. A second frequency modulating unit that outputs a second modulated wave generated as a result, and mixes the first and second modulated waves output by the first and second frequency modulating units with an audio signal, and A mixer for generating a multiplexed signal, for transmitting the video and audio multiplexed signal in baseband, wherein the receiving side signal processing unit unit converts the first modulated wave separated from the received video and audio multiplexed signal to a frequency A first frequency demodulation unit that demodulates and detects a frequency error between the frequency of the modulation reference carrier and the frequency of the first modulation wave from an amplitude shift of a synchronization signal included in the first modulation wave. A demodulation reference carrier generator that generates a demodulation reference carrier corrected for the frequency error detected by the first frequency demodulation unit, and a demodulation reference carrier that has the same ratio as the transmission side divider divides the modulation reference carrier. The receiving side frequency divider that divides the frequency and outputs a demodulated carrier having a different frequency, a second frequency demodulator that frequency demodulates the second modulated wave according to the demodulated carrier, and further includes a multiplex transmission device. A video / audio reproduction / display apparatus for reproducing / displaying the output video and audio signals is provided in a living space in a moving body.

Further, the information display device for a mobile object according to the present invention is a map information display device generated by multiplexing a guide sound signal and a map information display video signal including red, green, and blue primary color signals. A transmitting-side signal processing unit for transmitting a multiplexed signal, receiving the multiplexed signal for map information display, separating a guide audio signal and a video signal for map information display, and outputting data for video display; A multiplex transmission device having a reception-side signal processing unit, wherein the transmission-side signal processing unit includes a modulation reference carrier generator that generates a modulation reference carrier having a predetermined frequency, and color signals of three primary colors red, green, and blue. Among them, a synchronizing signal superimposing unit that superimposes a synchronizing signal for video display on the first color signal, a frequency signal generated by performing frequency modulation on the modulation reference carrier according to the first color signal output by the synchronizing signal superimposing unit. One modulated wave A first frequency modulating section for outputting, a first transmitting-side frequency dividing section for outputting a first modulated carrier obtained by dividing the frequency signal of the modulation reference carrier by half, and a control signal for controlling video display. As a serial signal, a first synthesis selector unit that superimposes a second color signal on which a synchronization signal is not superimposed, and the first modulation unit according to a second color signal output by the first synthesis selector unit. A second frequency modulator that outputs a second modulated wave generated by frequency-modulating the carrier, and a second frequency modulator that outputs a second modulated carrier obtained by dividing the frequency signal of the first modulated carrier by half. A second transmitting-side frequency divider, a second synthesizing selector unit that superimposes a control signal for controlling video display as a serial signal on a third color signal on which no synchronization signal is superimposed, and a second synthesizing selector unit. According to the output third color signal, the second A third frequency modulator that outputs a third modulated wave generated by frequency-modulating a modulated carrier, the first, second, and third output by the first, second, and third frequency modulators. A mixer for mixing the modulated wave with the audio signal for guidance to generate a multiplexed signal for map information display, the base station transmits the multiplexed signal for map information display, and the reception-side signal processing unit unit includes: While separating and frequency demodulating the first modulated wave including the first color signal superimposed with the synchronization signal from the received map information display multiplex signal, the frequency of the modulated reference carrier and the frequency of the first modulated wave A first frequency demodulator for detecting a frequency error of a frequency from an amplitude shift of a synchronization signal included in the first modulated wave, and generating a demodulation reference carrier wave in which the frequency error detected by the first frequency demodulator is corrected; Demodulation group A quasi-carrier generator, a first receiving-side frequency divider for outputting a first demodulated carrier obtained by dividing the frequency signal of the demodulated reference carrier by half, and output by the first receiving-side frequency divider According to the first demodulated carrier, a second frequency demodulation unit that frequency demodulates a second modulated wave including a second color signal on which a control signal for controlling video display is superimposed, the first demodulated carrier A second receiving-side divider that outputs a second demodulated carrier obtained by dividing the frequency signal by half; a video signal corresponding to the second demodulated carrier output by the second receiving-side divider; A third frequency demodulation unit for frequency demodulating a third modulated wave including a third color signal on which a control signal for controlling display is superimposed; and a map information display output from the multiplex transmission device. Video and audio playback and display device that reproduces and displays video and audio signals for guidance But on the living space of the inner.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram of a transmitting side of a multiplex transmission apparatus according to the present invention, and FIG. 2 is a block diagram of a receiving side of the multiplex transmission apparatus shown in FIG. FIG. 3 is an explanatory diagram for explaining the synthesizing of the synchronization signal, FIG. 4 is an explanatory diagram for explaining the synthesizing of the serial signal, and FIG. 5 is a band plan by the multiplex transmission apparatus according to the first embodiment.

The transmitting side of the video / audio signal multiplex transmission apparatus shown in FIG. 1 (hereinafter referred to as a transmitting side signal processing unit)
Is used to transfer data such as a horizontal synchronizing signal (hereinafter referred to as H signal), a vertical synchronizing signal (hereinafter referred to as V signal), video signals (hereinafter referred to as R, G and B signals) separated into three primary colors of red, green and blue, and control signals. The transmission data is created by arithmetic processing, the carrier is frequency-modulated in accordance with the transmission data to create a modulated wave, and multiplexed with an audio signal for transmission.

In the transmitting-side signal processing unit shown in FIG. 1, reference numeral 2 denotes first transmission data generated by superimposing a synchronizing signal (hereinafter referred to as a C signal) obtained by synthesizing an H signal and a V signal on a G signal. The synchronizing signal superimposing units 5 and 8 are control signal superimposing units that superimpose a control signal for controlling the display panel as serial data on the R signal and the B signal, respectively, to generate second transmission data and third transmission data. is there. Reference numeral 3 denotes a modulation reference carrier generator that generates a carrier whose frequency signal is modulated according to the first, second, and third transmission data.
Reference numerals 6 and 9 denote transmission-side frequency dividers for dividing the frequency signal of the carrier generated by the modulation reference carrier generator 3 at a predetermined ratio.
Is a first frequency modulation unit that frequency-modulates a carrier wave to generate a first modulated wave according to the first transmission data, and 7 and 10 correspond to the second and third transmission data. This is a second frequency modulation unit that frequency-modulates the carrier and generates second and third modulated waves, respectively. After the first, second, and third modulated waves are mixed with the audio signal by the mixer 11,
The signal is transmitted via the signal line 12 in a baseband system.

In the first embodiment, the carrier generated by the modulation reference carrier generator 3 is divided at a predetermined ratio by the transmission-side frequency divider 6 and the transmission-side frequency divider 9. Further, the first frequency modulating section 4 superimposes a synchronization signal on a video signal (a video signal of one of R, G, and B) and generates the highest frequency of the carrier in accordance with first transmission data generated. Modulate the band. Further, the second frequency modulating unit performs transmission-side frequency division in accordance with second and third transmission data generated by superimposing a control signal as serial data on the other two-color video signal on which the synchronization signal is not superimposed. The units 6 and 9 frequency-modulate the divided carrier to generate second and third modulated waves. Further, the first, second, and third modulated waves are mixed with an audio signal, and the audio signal is transmitted without modulation in a baseband system. This is a feature of the signal processing unit. If the wiring distance is short, the deterioration of the signal is negligible even when the baseband transmission is performed.

In this specification, a carrier generated by a modulation reference carrier generator serving as a reference for frequency division is a modulation reference carrier,
A carrier generated by dividing the modulated reference carrier at a predetermined ratio is called a modulated carrier. The frequency divider provided in the signal processing unit on the transmitting side is referred to as the frequency divider on the transmitting side irrespective of the number thereof. Regarding the frequency modulation units, regardless of the number, the frequency modulation unit that performs frequency modulation according to the first transmission data generated by superimposing the synchronization signal on the video signal is the first frequency modulation unit, and the control signal is A frequency modulation unit that performs frequency modulation according to second and third transmission data generated by being superimposed on a video signal is referred to as a second frequency modulation unit.

Next, the configuration and operation of the video / audio signal multiplex transmission apparatus according to the first embodiment will be described in more detail. The synchronizing signal superimposing section 2 performs an exclusive OR operation on the H signal and the V signal to generate a C signal, and outputs the output of the synchronizing signal synthesizing section 1 to the G signal.
The first transmission data is generated by being superimposed on a signal. At this time, the V signal (V-Sync) and H signal (H-Sync)
As shown in FIG. 3A, a non-logic signal is generated, and the generated C signal (C-Sync) is as shown in FIG. 3B. As shown in FIG. 4, the control signal superimposing units 5 and 8 use the C signal (C-Sync) and the V signal output from the synchronizing signal synthesizing unit 1 to control the control signals during the vertical blank period of the R signal and the B signal. As a serial signal to generate second and third transmission data. The serial signal to be superimposed is asynchronous, 8-bit, LSB first. At this time, the number of transmitted bytes is one byte to several bytes in one horizontal scanning period (hereinafter, referred to as 1H line) in the video blank period, and is placed on a plurality of blank lines, thereby completing one screen transfer period. Allows the transfer of multiple bytes.

When the number of control serial data to be superimposed on the R signal and the B signal is, for example, one byte per one horizontal line,
If 10 bytes are used during the blanking period, the transmission rate is 600 bytes / second, and a total of 1.2 Kbytes can be transmitted. Therefore, it can be used not only for display control but also for other control purposes. In this example, as shown in FIG. 5, screen mode switching control is used as display unit control, and one byte is used for display unit backlight brightness control, screen mode switching control is used for the R signal, and display unit backlight is used for the B signal. The brightness control is inserted, and the insertion position of each signal is superimposed on the first line of the vertical blank period. As described above, the transmission-side signal processing unit of the video / audio signal multiplex transmission apparatus according to the present invention generates transmission data by superimposing a synchronization signal and a control signal on an RGB video signal.

The modulation reference carrier generator 3 outputs the generated modulation reference carrier to the first frequency modulator 4 and the transmitting frequency divider 6. The first frequency modulation section 4 frequency-modulates the frequency signal of the modulation reference carrier according to the first transmission data output from the synchronization signal superposition section 2 to generate a first modulation wave. On the other hand, the transmission-side frequency divider 6 divides the frequency signal of the modulation reference carrier by, for example, half to generate a modulated carrier and outputs the modulated carrier to the second frequency modulator 7 and the transmission-side frequency divider 9. The second frequency modulation section 7 frequency-modulates the frequency signal of the modulated carrier according to the second transmission data output from the control signal superposition section 5 to generate a second modulated wave.

The transmitting-side frequency divider 9 further divides the frequency signal of the modulated carrier output from the transmitting-side frequency divider 6 by half.
The frequency-divided modulated carrier is output to the second frequency modulator 10. The second frequency modulator 10 frequency-modulates the frequency signal of the modulated carrier output from the transmission-side frequency divider 9 according to the third transmission data of the control signal superimposing unit 8 to generate a third modulated wave. I do. The first frequency modulator 4 and the second frequency modulators 7 and 10 output the first, second, and third modulated waves to the mixer 11 respectively, and after the mixer 11 mixes with the monaural audio signal. , Baseband transmission via the signal line 12. The frequency components of the superimposed audio signal are as shown in FIG.

The receiving side of the video / audio signal multiplex transmission apparatus shown in FIG. 2 (hereinafter referred to as the receiving side signal processing unit)
The first, second, and third modulated waves generated in the signal processing unit on the transmitting side are mixed with the monaural audio signal, and the video / audio multiplexed signal transmitted in baseband is separated to demodulate each signal. Then, the display panel is synchronized based on the demodulated synchronization signal, the display panel is controlled by a control signal so as to display based on the RGB signal, and the audio signal is output as audio.

In demodulating a video / audio multiplexed signal in the signal processing unit on the receiving side, it is necessary to tune the frequency and detect the frequency of the demodulated reference carrier. The video / audio signal multiplex transmission apparatus according to the present invention includes a modulation reference carrier generator that generates a modulation reference carrier and a frequency divider that divides the modulation reference carrier at a predetermined ratio in a transmission-side signal processing unit. Therefore, the frequency tuning can be performed by generating a demodulation reference carrier having the same frequency as the frequency of the modulation reference carrier. Although it is conceivable that the frequency of the modulation reference carrier deviates from a predetermined frequency due to temperature characteristics or the like, the first frequency demodulation unit 13 shown in FIG. 2 detects the frequency of the modulation reference carrier and generates a demodulation reference carrier. Since 16 is corrected, the tuning of the frequencies of the modulation reference carrier and the demodulation reference carrier is easy. Further, since the ratio for dividing the carrier frequency is determined, the frequency of each band can be tuned by dividing the demodulation reference carrier using the ratio.

For example, as shown in FIG. 5, assuming that the frequency of the modulation reference carrier, which is frequency-modulated by the first frequency modulation section 4 in response to the G signal on which the synchronization signal is superimposed, is 400 MHz, is shown in FIG. The transmission-side frequency divider 6 divides the modulation reference carrier by １ ／ to generate a 200 MHz modulated carrier. This modulated carrier is frequency-modulated by the second frequency modulator 7 in accordance with the R signal on which the control signal is superimposed.
Further, the transmission-side frequency divider 9 divides the modulated carrier (200 MHz) generated by the transmission-side frequency divider 6 by half, and divides it by 100.
Generate a modulated carrier in MHz.

In the transmission-side signal processing unit, the transmission-side frequency dividers 6 and 9 divide the frequency at a ratio of 1: 1/2: 1/4 based on the modulation reference carrier (400 MHz). Frequency tuning in the side signal processing unit may be performed in the highest frequency band. The other frequency components are each 1 / th of the frequency-tuned demodulated reference carrier.
Appears at 2/4.

FIG. 2 is a block diagram of the receiving side of the multiplex transmission apparatus according to the present invention. In FIG. 2, reference numeral 13 denotes a first frequency demodulator for demodulating a G signal in which a synchronizing signal is synthesized from a video / audio multiplex signal transmitted from the transmission-side signal processing unit, and 14 denotes a control serial signal in which a control serial signal is synthesized. A second frequency demodulation unit 15 for demodulating the R signal; a second frequency demodulation unit 15 for demodulating the B signal combined with the control serial signal;
Reference numeral 6 denotes a demodulation reference carrier generator for generating a demodulation reference carrier used in the frequency demodulation unit 13. Reference numeral 17 denotes a frequency-divided frequency signal of the demodulation reference carrier from the demodulation reference carrier generator 16. A receiving-side frequency divider 18 generates a demodulated carrier used by the demodulator 14. A frequency divider 18 divides the frequency signal of the demodulated carrier from the receiving-side frequency divider 17, and a reference signal used by the second frequency demodulator 15. A receiving-side frequency dividing section, 19 is a synchronization separating section for separating a synchronizing signal from the G signal demodulated by the first frequency demodulating section 13, and 20 is a synchronizing signal separating section from the R signal demodulated by the second frequency demodulating section 14. , Sync separation unit 1
9, a separation selector unit for separating a control signal using the C signal and the V signal separated from each other, and 21 a C signal and a V signal separated by the synchronization separation unit 19 from the B signal demodulated by the second frequency demodulation unit 15. A separation selector unit 22 that separates a control signal using a signal is a low-pass filter (LPF) unit that extracts only an audio monaural signal component from the video / audio multiplex signal transmitted from the transmission-side signal processing unit.

The receiving-side signal processing unit separates the video / audio multiplex signal transmitted from the transmitting-side signal processing unit into individual signals. The first frequency demodulation unit 13 frequency-demodulates the G signal on which the synchronization signal is superimposed.
At this time, the frequency shift is detected and the demodulation reference carrier generator 16 is corrected. More specifically, a synchronization signal is superimposed on the modulated G signal, and the synchronization signal amplitude is constant if there is no error in the frequency. That is, the first frequency demodulation unit 13 of the reception-side signal processing unit performs the correction by detecting a deviation in the amplitude of the synchronization signal included in the first modulated wave.

The sync separation section 19 is provided with a vertical sync signal (V-Syn
c), horizontal synchronization signal (H-Sync), and composite synchronization signal (CS
ync). The second frequency demodulation unit 14 demodulates the R signal on which the screen mode switching control serial signal is superimposed. The demodulation carrier is the demodulation reference carrier used in the first frequency demodulation unit 13 and transmitted to the reception-side frequency dividing unit 17. To obtain a demodulated carrier. The control signal is separated by the separation selector unit 20 to be a screen mode switching control signal. A second frequency demodulation unit 15 demodulates the B signal on which the display backlight brightness control serial signal is superimposed. The demodulation carrier is obtained by dividing the frequency signal of the demodulation carrier used in the second frequency demodulation unit 14 on the reception side. The frequency is divided by the peripheral unit 18 to obtain a demodulated carrier. The control signal is separated by the separation selector unit 21 to be a display backlight luminance control signal. As for the audio signal, a signal outside the audio band is removed (fc = 20 kHz) by the LPF unit 22 and input to the audio amplifier of the display unit.

In a conventional video / audio signal multiplex transmission apparatus,
The carrier is generated and frequency-modulated for each of the R, G, and B video signals, the audio signal on which the control signal is superimposed, and the remote control signal. However, the video / audio signal multiplex transmission apparatus according to the first embodiment performs modulation (reception). Since a demodulation (reference) carrier generator section in the side signal processing unit and a first (second) frequency divider for dividing the modulation (demodulation) reference carrier at a predetermined ratio are provided, the number of carrier generators is reduced. Could be reduced.

Conventionally, it has been necessary to construct a phase locked loop (PLL) circuit by the number of carriers. However, since each carrier is obtained by dividing the modulation reference carrier by a predetermined ratio, the receiving side signal processing unit modulates the modulation reference carrier in the highest frequency band modulated according to the video signal on which the synchronization signal is superimposed. Since the demodulation reference carrier is generated by correcting the frequency of the demodulation reference carrier based on the deviation of the amplitude of the synchronization signal, the number of PLL circuits that take the frequency tuning during demodulation can be reduced. .

In the above embodiment, the control signal to be superimposed is converted into a serial signal. However, the signal to be superimposed during the vertical blank period is not limited to a digital signal, and an analog signal may be superimposed depending on the application. Is also possible.
In addition, analog and digital signals are converted for each horizontal scanning period,
More information can be transmitted by switching for each signal line.

[0035]

According to the present invention, the carrier wave is frequency-modulated according to the video signal on which the synchronizing signal and the control signal are superimposed, and mixed with the audio signal to perform baseband transmission. The effect is achieved. In addition, since a reference carrier generator and a frequency divider for dividing a modulated (demodulated) reference carrier at a predetermined ratio are provided, the carrier generator,
The number of frequency modulation (demodulation) units can be reduced, and the device can be made compact. Therefore, the mobile information display device using the multiplex transmission device according to the present invention,
The ease of installation on moving objects, such as vehicles, aircraft, and ships, where living space is limited, has been improved.

Also, since the video signal is subjected to FM modulation and then transmitted to the baseband, crosstalk in the transmission line and the influence of extraneous noise, which is an obstacle to image quality, are reduced. Can be provided to people.

Further, the number of parts constituting the apparatus is reduced, so that an increase in the unit manufacturing cost can be suppressed, and the circuit configuration is simplified, so that the production efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a transmission side of a multiplex transmission apparatus according to the present invention.

FIG. 2 is a configuration diagram of a receiving side of the multiplex transmission apparatus according to the present invention.

FIG. 3 is a diagram for explaining synchronizing signal synthesis according to the present invention.

FIG. 4 is a diagram for explaining serial signal synthesis according to the present invention.

FIG. 5 is a diagram for explaining multiplex transmission according to the present invention.

FIG. 6 is an overall configuration diagram of a conventional multiplex transmission device.

FIG. 7 is a band plan of a conventional multiplex transmission device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synchronization signal synthesis part 2 Synchronization signal superposition part 3 Modulation reference carrier generator 4 First frequency modulation part 5 Control signal superposition part 6 Transmitting frequency dividing part 7 Second frequency modulating part 8 Control signal superposing part 9 Transmission side Circumferential unit 10 Second frequency modulation unit 11 Mixer 12 Signal line 13 First frequency demodulation unit 14 Second frequency demodulation unit 15 Second frequency demodulation unit 16 Demodulation reference carrier generator 17 Reception-side frequency divider 18 Reception Side frequency divider 19 Synchronization separator 20 Separation selector 21 Separation selector 22 LPF (Low Pass Filter) 23 Speaker 24 Control unit 25 Display panel 31 FM modulator 32 FM modulator 33 FM modulator 34 FM modulator 35 AM Modulation / multiplexing unit 36 Mixer 37 Signal line 38 FM demodulation unit 39 FM demodulation unit 40 FM demodulation unit 41 FM demodulation unit 42 Synchronization separation unit 43 AM modulation 44 speaker 45 display panel

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) AA07 AA10 AA12

Claims (5)

[Claims] 1. A transmission-side signal processing unit for transmitting a video-audio multiplexed signal generated by multiplexing an audio signal and a video signal including three primary color signals of red, green, and blue, and the transmission-side signal processing unit And a receiving-side signal processing unit for receiving the video / audio multiplexed signal transmitted via the signal line connected to the receiving side, separating the video signal and the audio signal, and outputting data for performing video display. In the multiplex transmission apparatus, the transmission-side signal processing unit unit superimposes a synchronization signal for video display on one of three color signals of a modulation reference carrier generator that generates a modulation reference carrier of a predetermined frequency. A first frequency modulator that outputs a first modulated wave generated by frequency-modulating the modulated reference carrier according to the color signal on which the synchronization signal is superimposed, the frequency signal of the modulated reference carrier is output. A transmitting-side frequency divider that outputs a modulated carrier wave having a different frequency, a control signal for controlling image display is superimposed on at least one color signal on which a synchronization signal is not superimposed, and the control signal is superimposed on the color signal. Accordingly, a second frequency modulator that frequency-modulates the modulated carrier and outputs a second modulated wave, and outputs the first and second modulated waves output by the first and second frequency modulators as audio. A mixer for generating a video / audio multiplexed signal by mixing with a signal, and transmitting the video / audio multiplexed signal in a baseband; wherein the receiving side signal processing unit unit is separated from the received video / audio multiplexed signal. A first frequency demodulation unit that frequency-demodulates the first modulation wave, and detects a frequency error between the frequency of the modulation reference carrier and the frequency of the first modulation wave, is detected by the first frequency demodulation unit. A demodulation reference carrier generator that generates a demodulation reference carrier with a corrected wave number error, the transmission-side divider divides the demodulation reference carrier at the same ratio as that at which the modulation reference carrier is divided, and demodulates the demodulation carrier at a different frequency. Multiplex transmission, comprising: a receiving-side frequency divider for outputting, a second frequency demodulator for frequency-demodulating the second modulated wave according to a demodulated carrier, and outputting demodulated video and audio signals. apparatus. 2. The reception-side signal processing unit according to claim 1, wherein the reception-side signal processing unit includes a first frequency demodulation unit that detects an amplitude shift of a synchronization signal included in a first modulation wave. Multiplex transmission equipment. 3. The transmission-side signal processing unit includes a control signal superimposing unit that superimposes, as a serial signal, a control signal for controlling video display on at least one color signal on which no synchronization signal is superimposed. The multiplex transmission apparatus according to claim 1, wherein 4. A transmitting-side signal processing unit for transmitting a video / audio multiplexed signal generated by multiplexing an audio signal and a video signal containing red, green, and blue primary color signals, and receiving the video / audio multiplexed signal. To separate the video and audio signals,
A multiplex transmission device having a reception-side signal processing unit that outputs data for performing video display, the transmission-side signal processing unit includes a modulation reference carrier generator that generates a modulation reference carrier having a predetermined frequency, A first modulation wave generated by superimposing a synchronizing signal for video display on one of the three primary color signals, and frequency modulating the modulation reference carrier according to the color signal on which the synchronizing signal is superimposed. A first frequency modulating section for outputting a frequency-divided frequency signal of the modulation reference carrier and a transmitting-side frequency dividing section for outputting a modulated carrier having a different frequency, and a video signal on at least one color signal on which no synchronization signal is superimposed. A second frequency modulation unit that superimposes a control signal for controlling display as a serial signal and outputs a second modulation wave generated by frequency-modulating the modulation carrier according to the color signal; And a mixer that mixes the first and second modulated waves output by the second frequency modulator with an audio signal to generate a video / audio multiplexed signal, and transmits the video / audio multiplexed signal in baseband. The receiving-side signal processing unit unit frequency-demodulates the first modulated wave separated from the received video / audio multiplexed signal, and generates a frequency error between the frequency of the modulated reference carrier and the frequency of the first modulated wave. A first frequency demodulation unit for detecting from the amplitude shift of a synchronization signal included in the first modulation wave, a demodulation reference carrier for generating a demodulation reference carrier corrected for a frequency error detected by the first frequency demodulation unit The generator, the receiving-side divider that divides the demodulation reference carrier at the same ratio as the transmission-side divider divides the modulation reference carrier, and outputs demodulation carriers having different frequencies. A second frequency demodulator for frequency demodulating the second modulated wave, and a video / audio reproduction / display device for reproducing / displaying the video signal and the audio signal output from the multiplex transmission device. An information display device for a mobile object, which is provided in a living space. 5. A transmitting-side signal processing unit for transmitting a map information display multiplexed signal generated by multiplexing a guide audio signal and a map information display video signal including red, green, and blue primary color signals. A multiplex transmission device having a receiving-side signal processing unit for receiving the multiplexed signal for map information display, separating an audio signal for guidance and a video signal for map information display, and outputting data for performing video display. Having, the transmission-side signal processing unit section, a modulation reference carrier generator that generates a modulation reference carrier of a predetermined frequency, red, green,
Among the three primary color signals of blue, a synchronizing signal superimposing section for superimposing a synchronizing signal for video display on the first color signal, and the modulation reference carrier wave having a frequency according to the first color signal output by the synchronizing signal superimposing section. A first frequency modulator for outputting a first modulated wave generated by modulation, and a first transmitting side part for outputting a first modulated carrier obtained by dividing the frequency signal of the modulation reference carrier by half. A first synthesizing selector unit for superimposing a control signal for controlling video display as a serial signal on a second color signal on which a synchronizing signal is not superimposed, and a second synthesizing unit output by the first synthesizing selector unit A second frequency modulator that outputs a second modulated wave generated by frequency-modulating the first modulated carrier according to the color signal, and divides the frequency signal of the first modulated carrier by half; A second transmission-side frequency divider that outputs the second modulated carrier wave that has been circulated, A second synthesizing selector unit that superimposes a control signal for controlling video display as a serial signal on a third color signal on which a synchronization signal is not superimposed, on a third color signal output by the second synthesizing selector unit Accordingly, a third frequency modulator that outputs a third modulated wave generated by frequency-modulating the second modulated carrier, the first frequency output by the first, second, and third frequency modulators. , A mixer for mixing the second and third modulated waves with the audio signal for guidance to generate a multiplexed signal for map information display, and for transmitting the multiplexed signal for map information baseband transmission, The side signal processing unit unit separates and frequency-demodulates the first modulation wave including the first color signal in which the synchronization signal is superimposed from the received multiplex signal for map information display, and demodulates the frequency. The first change A first frequency demodulator for detecting a frequency error of the frequency of the wave from an amplitude shift of a synchronization signal included in the first modulated wave, a demodulation reference carrier corrected for the frequency error detected by the first frequency demodulator; , A first receiving-side frequency divider for outputting a first demodulated carrier obtained by dividing the frequency signal of the demodulated reference carrier by half, and a first receiving-side frequency divider A second frequency demodulation unit that frequency-demodulates a second modulated wave including a second color signal on which a control signal for controlling video display is superimposed according to the first demodulated carrier output by the unit; A second receiving-side frequency divider that outputs a second demodulated carrier obtained by dividing the frequency signal of the demodulated carrier by half, to a second demodulated carrier output by the second receiving-side frequency divider A third color signal on which a control signal for controlling video display is superimposed according to A third frequency demodulator for frequency demodulating a third modulated wave including: a video and audio reproduction for reproducing and displaying the map information display video signal and the guidance audio signal output from the multiplex transmission device. An information display device for a mobile object, wherein the display device is provided in a living space in the mobile object.