JPH04142893A - Receiver - Google Patents

Abstract

PURPOSE:To prevent a fully black level pattern or a white noise pattern from being displayed by outputting a still picture signal just before defect of reception stored in a memory means onto a monitor on the occurrence of defect of reception. CONSTITUTION:While the reception state is excellent, a video signal and an audio signal demodulated by a tuner means 3 are outputted to a monitor 4 as they are so as to allow the broadcast is viewed, and the video signal is simultaneously fed to a memory means 3b, rewritten sequentially and stored in the unit of patterns. When the defect of reception is reduced, a changeover means is switched and a picture signal stored in the memory means 3b is read out continuously as a still picture and outputted onto the monitor 4, and preferably an audio output is muted. Thus, a still picture signal just before defect of reception is displayed onto the screen of the monitor, a fully black level pattern or a white noise pattern is not generated and the disturbance of received pattern is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a receiving device such as a satellite broadcast tuner.

[E-Summary of the Invention] The receiving device of the present invention includes: - A memory means is disposed after the means for receiving and demodulating, and the demodulated video signal is sequentially stored on a screen-by-screen basis. In addition, an abnormality detection means for detecting a reception abnormality, and a switching means capable of switching and outputting the video signal demodulated by the tuning means and the still image signal read from the memory means,
When a reception abnormality is detected, the still image signal stored in the memory means is outputted to the monitor device instead of the demodulated signal from the tuner means.
To prevent a screen not appearing or a noise state from occurring when poor reception occurs. Furthermore, a character generator generates a predetermined character signal when the abnormal reception state continues for a predetermined period of time, and a synthesizing means synthesizes the output character signal with the static image signal read from the memory means and outputs the result. If the poor reception continues for a certain amount of time, a static image will be displayed on the screen along with a message explaining that the reception is currently poor. It is something.

[Prior Art] With the implementation of satellite broadcasting, for example, an automatic tracking antenna is installed on a moving object such as a queue or a bus to receive satellite broadcasting.
A mobile reception system has been proposed that allows broadcast programs to be viewed on a monitor device installed in a vehicle.

[Problems to be Solved by the Invention] However, in queues and while buses are running, there are many obstacles to antenna reception, such as tunnels, high-rise buildings, and overpass guards. For this reason, it is impossible to always receive broadcasts well and view proper images on a monitor device, and each time there is an obstacle mentioned above, reception becomes unavailable or poor for a few seconds to several minutes, and the screen is completely blank. It becomes a black state or a white noise state. There is a problem in that such screen defects are very unsightly for viewers and are a major hindrance to the actual operation of the mobile reception system.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and includes a tuner means for receiving a broadcast signal and demodulating it into a video signal and an audio signal, and a tuner means for receiving the broadcast signal and demodulating the demodulated video signal. A memory means for sequentially storing data on a screen-by-screen basis, an abnormality detection means for detecting a reception abnormality, a video signal (and audio signal) demodulated by the tuner means, and a still image signal read out from the memory means are switched. To provide a receiving device which is provided with a switching means capable of outputting a still image signal, and configured so that when a reception (+-¥ abnormality is detected), a still image signal stored in a memory 1,000 F¥L is output.

Also provided is a character generator that generates a predetermined character signal when the abnormal reception state continues for a predetermined period of time, and a composition means that combines the output character signal with the still image signal read from the memory means and outputs the result. do it like this.

[Function] While the reception condition is good, the video signal and audio signal demodulated by the tuner means are output as they are to the monitor device so that the broadcast can be viewed, and at the same time the video signal is supplied to the memory means. It is sequentially rewritten and memorized at screen m. Then, when poor reception is detected, the switching means is switched to continuously read the image signal stored in the memory means as a still image and output it to the monitor device, and preferably also output audio. By doing so, when there is a poor reception, a still image immediately before the poor reception is displayed on the monitor screen, a noise screen or a completely black screen does not occur, and it is possible to eliminate disturbances on the reception screen.

Furthermore, if a character generator and a compositing means are provided, if poor reception persists (for example, for more than 6 seconds), a message to explain the poor reception will be displayed together with a still image to inform the viewer. You can also report it.

[Embodiment] FIG. 1 is a configuration diagram of a satellite broadcast mobile reception system that employs a satellite broadcast tuner according to an embodiment of the present invention.
1 is an automatic tracking type BS antenna that can be installed in a vehicle, etc., and 2 is a BS converter that converts the 12 GHz band radio waves received by the BS antenna 1 into a first intermediate frequency (1.03 to 1°33 GHz). .

3 is a satellite broadcasting tuner of the present embodiment, which selects a desired channel from the received signal converted into the first intermediate frequency and supplied, and further selects a desired channel from the received signal converted to the first intermediate frequency, and further selects 134.26 MHz or 402.78 MHz.
After converting to a second intermediate frequency of MHz, the video signal and
It is comprised of a satellite broadcast receiving device section 3a that demodulates and outputs an R stereo audio signal, and a still image memory device section 3b that includes a field memory that stores the demodulated video signal in the 99th field. Note that the still image memory device section 3b will be described later.

Reference numeral 4 denotes a monitor device, from which broadcasts selected and demodulated by the satellite broadcast tuner 3 are outputted for viewing.

When such a mobile receiving system is installed on a train, bus, etc., even when the receiving direction changes as the vehicle moves, the automatic tracking type BS antenna 1 allows accurate broadcasting even when the vehicle is moving. Although radio waves can be received and satellite broadcast programs can be viewed in the vehicle, if poor reception occurs due to the satellite broadcast radio waves being blocked by driving in a tunnel or by a high-rise building, etc., the still image memory device section 3b By functioning, the satellite broadcast tuner 3 of this embodiment supplies the monitor device 4 with a static image signal immediately before the poor reception.

The still image memory device section 3b is configured as shown in FIG. 2, for example.

Reference numeral 1o indicates a video signal input terminal section into which the video signal demodulated by the satellite broadcast receiver section 3a is manually input, and 11° and 12 indicate the L and R audio signals demodulated by the satellite broadcast receiver section 3a. This is an audio signal input terminal section.

The video signal No. 1.1 input manually from the video signal input terminal section 10 is passed through the amplifier 13 to the a contact of the switching circuit 14, which is composed of an electronic switch such as a high-speed diode, and the receiver (i') Synchronous signal detection circuit 1 configured to detect synchronizing signal fluctuations during demodulation (+'i 5-J)
5 and the decoder 16.

On the other hand, the audio signal input terminal section 11. The signal input from +2 is sent to the switching circuit +2, which is also composed of electronic switches.
41. , , +4R are supplied to the a contacts, respectively.

17 is a decoder 16, for example, an A/D converter that converts the video signal decoded into a luminance signal and a color signal into digital signals, and 18 is a field memory unit that stores the video signal converted into digital data in units of fields. be.

The field memory section 18 has a storage capacity for, for example, 8 fields (4 frames), and under normal conditions (= when there is no poor reception), the video signal supplied from the satellite broadcasting receiving device section 3a is stored in m order of images. It is controlled so that it is sequentially rewritten and stored. In other words, field memory section 1
8 always stores still images for the most recent four screens.

1ε] is a 1]/Δ converter, and 20 is an encoder, which converts the digital data read from the field memory unit 18 again into an analog video signal, as will be described later. The output of the encoder 20 is sent to the switching circuit 1 via the combining circuit 21.
It is supplied to the b contact of No.4.

22 is a character generator, and 23 is a timing signal generation circuit.

24 is the A/D converter 17. field memory 1
8. A system controller using a microcomputer that supplies control signals to the D/Δ converter 19, etc.
Further, this microcomputer 24 has a field memory section 18, a timing generation circuit 23, a character generator 22, and switching circuits +4V, +4L, +4H based on the detection signal from the synchronization signal detection 1IIj path 15.
provides operation control signals to the In addition, the switching circuit +4V, +
The switching of each a contact and b contact of 4L and 14R is controlled in conjunction with each other.

The output of the switching circuit +4V is supplied to the video signal output terminal section 26 via the amplifier 25, and the switching circuit 14L,
1.4 H output is audio A, i output terminal section 27.28
is supplied to Output terminal portions 2E;
, R audio signals are supplied.

The operation of the still image memory device section 3b configured in this way will be explained.

While the stable 1tII signal is detected by the synchronization signal detection circuit I5, the system controller 24 determines that there are no radio wave obstructions and the satellite broadcasting radio waves are being received well by the B8 antenna 1, and the switching circuit 14V , 14L,
Connect +4R to A contact, input terminal part to, I+, 1
The human-powered video signal from 2 and 1. , R audio signals are supplied as they are to the output terminal sections 26, 27, and 28, and output to the monitor device 4. At the same time, the hidden address data and the timing signal generation circuit 2 are stored in the field memory section 18.
3 and provide the write control signal through the field! The image information entered manually is recorded sequentially (the operation is continued so that the latest four screens of video data are always held in the field memory section 18).

However, when the synchronization signal detection circuit 15 detects a break or disturbance in the synchronization signal, the system controller 14 determines that a poor reception has occurred, and the switching circuit 1
4V, 1417, and 14R are connected to the b contacts, and the video signal supplied from the satellite broadcasting receiving device section 3a and ■-1.
The R audio signal is not supplied to the monitor device 4.

Then, a read control signal is supplied to the field memory unit 18 along with the read address data via the timing signal generation circuit 23, and from the oldest data among the currently held image data, that is, the frame in which the synchronization signal abnormality has been confirmed. Image data of four frames 1j11 are read out continuously as still images. The read image data of four frames before is sent to the D/Δ converter 19, encoder 2o,
The signal is outputted via the synthesis circuit 21 and the +4V switching circuit and the +4V terminal, and is supplied to the monitor device 4. By continuously reading out and outputting the image data, the monitor device 4 displays a still image almost immediately before (four frames before) the reception failure occurs. On the other hand, the audio signal is cut by the switching circuits I4L and 14R, and no audio is output from the monitor device 4.

Of the four screens of signals recorded in the field memory section 18, the signal of the frame immediately before the reception failure was detected may have been affected by the radio wave interference that caused the reception failure. Therefore, by outputting the image four frames before as described in 1-1, even the still image output from the field memory section 18 becomes a noise screen and is displayed on the monitor, making the image look dull. possibility can be reduced. However, it does not necessarily have to be the fourth frame ii (it may be set based on the recorded capacity of the mounted field memory section 18).

In this embodiment, if the synchronization signal detection circuit 15 detects a stable synchronization signal within 6 seconds after the poor reception state described in (a) occurs, the normal control state described above is restored and the satellite broadcasting is started. A demodulated signal by the receiving device section 3a is supplied to the monitor device 4.

However, if a stable synchronization signal is not detected even after 6 seconds have passed due to poor reception, the system controller 24 supplies character designation information to the character generator 22, and also outputs character specification information to the timing signal generation circuit. A character output control signal is supplied via 23. The designated character is, for example, a character display character such as ``The radio wave is currently down. Please wait for a while.'' J, and this character signal is output based on the character output control signal.

The output character signal is combined with the still image signal output from the field memory unit 18 by the high-speed switching stage F in the combining circuit 21, and is displayed as a still image on the monitor device 4.

In this way, when a relatively long radio wave failure occurs, by displaying an explanatory caption, it is possible to prevent viewers from feeling uneasy. Of course, it is possible to set the character display timing to a time other than 6 seconds, but if the poor reception period is about 1 to 3 seconds, the viewer will hardly feel any discomfort if the video is simply a static IL image. Therefore, in the case of such short-term poor reception, the character display becomes an eyesore, and it is preferable not to display the character.

By the way, in the satellite broadcast tuner 3 of this embodiment, the satellite broadcast receiver section 3a and the still image memory device section 3b are integrally formed, and there is no need for additional equipment in the system. , there will be no inconveniences different from conventional ones when installing it on a bus or the like. Alternatively, both memory devices 3b may have a circuit configuration that stores component video signals, or the composite video signal may be stored as is in the field memory.

Further, although the explanation has been given using an example of a satellite broadcast tuner, the present invention is applicable not only to satellite broadcasts but also to receiving apparatuses for broadcasts of other systems with significant directivity. Furthermore, the receiving apparatus of the present invention is not limited to a receiving system mounted on a moving object, but can also be applied to a fixed-position receiving system in places where radio waves are likely to be disrupted by incoming airplanes or the like.

[Effects of the Invention 1 As explained above-12, the receiving device of the present invention outputs the still image signal immediately before the reception failure stored in the memory means to the monitor device when reception failure occurs. This has the effect that the viewer can watch without any discomfort due to poor reception, such as an all-black screen or a white noise screen. Ideal for

Furthermore, if poor reception continues for a predetermined period of time, a message is displayed to alleviate the viewer's anxiety.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a satellite broadcast receiving system employing an embodiment of the present invention, and FIG. 2 is a block diagram of a still image memory device section of an embodiment of the present invention. 1 is a BS antenna, 2 is a BS converter, 3 is a satellite broadcast tuner, 3a is a satellite broadcast receiver section, 3b is a still picture memory device section, 4 is a monitor device, 10 is a video signal input terminal section, 11.12 is a Audio signal 1 [3 Input terminal section, 14V, 1414, 14R is switching circuit, 1
5 is a synchronization signal detection circuit, I8 is a field memory section, 2
1 is a synthesis circuit, 22 is a character generator, 23 is a timing generation circuit, 24 is a system controller, 2
Reference numeral 6 indicates a video signal output terminal section, and reference numerals 27 and 28 indicate an audio signal output terminal section.

Claims (2)

[Claims] (1) A tuner means that receives a broadcast signal and demodulates it into a video signal and an audio signal, a memory means that can sequentially store and rewrite the demodulated video signal one screen at a time, and an abnormality that detects an abnormality in the reception state. A detection means and a switching means capable of switching and outputting a video signal demodulated by the tuner means and a still image signal read from the memory means,
A receiving device characterized in that, when an abnormality in the reception state is detected by the abnormality detecting means, the still image signal stored in the memory means is first outputted via the switching means. (2) a character generator that generates a predetermined character signal when the abnormal reception state detected by the abnormality detection means continues for a predetermined period of time; 2. The receiving device according to claim 1, further comprising a combining means for combining and outputting the combined result.