JP2007159161A - Receiver and receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To switch receiving channels by determining if recovery is to be made when broadcast quality deteriorates. <P>SOLUTION: A channel switching control section 101 determines that deterioration in broadcast quality is caused by shut-off of received radio wave when a time-varying amount of AGC voltage is increased to a first threshold or more, so that it holds a receiving channel. When the AGC voltage is kept equal to or higher than a second threshold for a first predetermined switching time after the increase of the time-varying amount to the first threshold or more, the control section 101 switches receiving channels even if deterioration in broadcast quality is caused by shut-off of received radio wave. When the AGC voltage is kept increased for a second predetermined switching time or more while the time-varying amount of the AGC voltage is less than the first threshold, the control section 101 determines that deterioration in broadcast quality is caused by a move of a vehicle, so that it switches receiving channels. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a receiving apparatus and a receiving method, and more particularly to a receiving apparatus and a receiving method for switching channels by identifying whether or not deterioration is recovered when broadcast quality deteriorates.

  In recent years, with the diversification of mobile broadcasting, it has become possible to mount a receiving device that receives analog broadcasting, digital broadcasting, or both on a vehicle. Further, in such a receiving apparatus, a conventional technique for switching between analog broadcasting and digital broadcasting or channel switching when an electric field fluctuates depending on the surrounding environment of the vehicle and broadcast quality such as image quality and sound quality deteriorates is disclosed. ing.

  For example, Patent Document 1 discloses a conventional technique for switching to reception of an analog broadcast having the same content when a deterioration in broadcast quality is detected during reception of a digital broadcast. Patent Document 2 discloses a conventional technique in which radio waves of a plurality of channels are received by a plurality of tuners, and when the broadcast quality of one channel is deteriorated, the channel is switched to another channel having a good broadcast quality. Patent Document 3 discloses a conventional technique for determining deterioration of broadcast quality based on an automatic gain control voltage (hereinafter referred to as “AGC voltage”).

JP-A-11-234227 JP 11-284925 A JP 09-307823 A

  In the prior art of Patent Document 1, when the vehicle is moving out of the area of the broadcast service, it is possible to detect the deterioration of the broadcast quality of the digital broadcast and switch to the reception of the analog broadcast of the same content. However, if the vehicle is hidden behind the shield and shielded from radio waves, and the radio wave is momentarily interrupted, digital broadcasts will be sent to analog broadcasts even though the deterioration in broadcast quality is restored by the vehicle coming out from behind the shield. There was a problem of switching to.

  Further, in the prior art of Patent Document 2, when radio waves of a plurality of channels are received by a plurality of tuners and the broadcast quality of one channel is deteriorated, it is possible to switch to another channel having a good broadcast quality. However, as in the above case, since it is not possible to distinguish between broadcast quality deterioration due to instantaneous interruption of radio waves and broadcast quality deterioration due to vehicle movement, there is a problem that even when the broadcast quality deterioration recovers, the channel is switched to another channel. was there.

  In the prior art of Patent Document 3, it is possible to determine the deterioration of broadcast quality based on the AGC voltage. However, as in the case described above, it is impossible to distinguish between broadcast quality deterioration due to instantaneous interruption of radio waves and broadcast quality deterioration due to vehicle movement, so even if the broadcast quality deterioration recovers, the screen before the broadcast quality deteriorates is displayed. There was a problem of switching to freeze or mute.

  The present invention has been made to solve the above-described problems of the prior art, and provides a receiving apparatus and a receiving method for switching channels by identifying whether or not the deterioration is restored when the broadcast quality is deteriorated. The purpose is to do.

  In order to solve the above-described problems and achieve the object, a receiving device according to the invention of claim 1 is a receiving device equipped with a channel for switching broadcasting and mounted on a mobile body, and the radio wave intensity received by the channel. A quality evaluation signal generating means for generating a quality evaluation signal for evaluating deterioration of broadcast quality, which is the quality of the broadcast, based on a time change of the radio frequency, and using the quality evaluation signal generated by the quality evaluation signal generating means, Channel switching control means for discriminating between the deterioration of the broadcast quality due to a momentary interruption and the deterioration of the broadcast quality due to the movement of the mobile body and controlling the switching of the channel is provided.

  The receiving device according to the first aspect of the present invention is a receiving device including a channel selection unit that switches a broadcast to be received, and switches the channel selection unit based on the radio wave intensity in the broadcast signal of the broadcast selected by the channel selection unit. Channel switching control means for controlling and broadcast information display means for displaying information related to the broadcast received when the received broadcast is switched when the channel selection switching condition in the channel switching control means is satisfied. .

  According to the first aspect of the present invention, when the reception channel is switched, the identification information of the channel after the switching related to the reception channel and the switching information including the switching time are displayed on the output device that outputs the analog broadcast or the digital broadcast. Therefore, a user-friendly TV image display becomes possible.

  Further, the receiving device according to the second and third aspects of the present invention is a receiving device including a channel selection unit that switches a broadcast to be received, and the channel selection unit is based on the radio wave intensity in the broadcast signal of the broadcast selected by the channel selection unit. Channel switching control means for controlling the switching of the channel, and response request display means for displaying a response request as to whether or not to switch the received broadcast when the channel selection switching condition in the channel switching control means is satisfied. The means controls the switching of the channel selection unit based on a response to the response request. In addition, when no response is made to the response request for a predetermined time, switching of the channel selection unit is controlled.

  According to the second and third aspects of the present invention, when switching the reception channel, the output device that outputs analog broadcast or digital broadcast, the identification information of the channel after the switching related to the reception channel, the switching time, and the response request whether or not to switch Since the switching information consisting of is displayed, user-friendly TV image display becomes possible. In addition, since the reception channel is switched according to the response to the switching information from the output device, a user-friendly TV image display becomes possible.

  According to a fourth aspect of the present invention, there is provided a receiving apparatus including a channel selection unit that switches a broadcast to be received, wherein the channel selection unit is switched based on a radio wave intensity in a broadcast broadcast signal selected by the channel selection unit. Channel switching control means for controlling the channel switching control means, and when the channel switching control condition in the channel switching control means is satisfied, there is a switching information input means for inputting information relating to the received broadcast, and the channel information is input by the switching information input means. The switching of the channel selection unit is controlled based on the received broadcast information.

  According to the fourth aspect of the present invention, when switching the reception channel, the switching information for selecting and inputting the reception channel is displayed on the output device that outputs the analog broadcast or the digital broadcast, and the switching channel is switched to the reception channel selected and input. As a result, user-friendly TV image display is possible.

  According to the first aspect of the present invention, when the reception channel is switched, the output device for outputting the analog broadcast or the digital broadcast is configured to display the channel identification information regarding the reception channel after switching and the switching information including the switching time. The user-friendly television image display can be achieved.

  According to the second aspect of the present invention, when the reception channel is switched, the output device for outputting the analog broadcast or the digital broadcast receives the identification information of the channel regarding the reception channel after switching, the switching time, and the response request whether to switch. Since the switching information is displayed, it is possible to display a user-friendly TV image.

  According to the invention of claim 3, since the reception channel is switched according to the response to the switching information from the output device, there is an effect that a user-friendly television image display becomes possible.

  According to the fourth aspect of the present invention, when the reception channel is switched, the switching information for selecting and inputting the reception channel is displayed on the output device that outputs the analog broadcast or the digital broadcast, and the reception channel selected and input in the switching information is displayed. Since switching is configured, there is an effect that a user-friendly television image display becomes possible.

  Exemplary embodiments of an in-vehicle television device according to the present invention will be described below in detail with reference to the accompanying drawings. In the first embodiment, based on the AGC voltage for controlling the gain of the intermediate frequency amplifier and the amount of change in the AGC voltage, broadcast quality deterioration due to instantaneous interruption of radio waves and broadcast quality deterioration due to vehicle movement are identified, and the reception channel is switched. The case will be described. Further, in the second embodiment, based on the AGC voltage for controlling the gain of the high-frequency amplifier and the amount of change in the AGC voltage, the broadcast quality deterioration due to instantaneous interruption of radio waves and the broadcast quality deterioration due to vehicle movement are identified, and the reception channel is set. A case of switching will be described.

  In the first embodiment, the AGC voltage that controls the gain of the intermediate frequency amplifier and the amount of change in the AGC voltage are used to identify broadcast quality degradation due to instantaneous interruption of radio waves and broadcast quality degradation due to vehicle movement, and A case of switching will be described. Here, (1) the outline and features of the in-vehicle television device, (2) the configuration of the in-vehicle television device, (3) an example of the time change regarding the received radio wave intensity, the AGC voltage, and the change amount of the AGC voltage of the in-vehicle television device, (4 ) Example of display image of switching information, (5) Channel switching control procedure for identifying deterioration of broadcast quality due to instantaneous interruption of radio wave and deterioration of broadcast quality due to movement of vehicle, (6) Before instantaneous interruption of received radio wave Channel switching control procedure for storing vehicle position, reception time, reception channel, (7) Channel switching control procedure for confirming deterioration of broadcast quality due to vehicle movement multiple times, (8) AGC voltage change amount Channel switching control procedure for confirming deterioration of broadcast quality due to vehicle movement based on time average value, (9) Channel for changing reception channel switching time according to vehicle speed Switching control procedure will be described in the order of the channel switching control procedure for changing the switching time in accordance with (10) receiving channel.

(1) Overview and Features of the In-Vehicle TV Device First, the overview and features of the in-vehicle TV device according to the first embodiment will be described. FIG. 1 is a functional block diagram of the configuration of the receiving apparatus according to the first embodiment. As shown in the figure, the in-vehicle television device 1 of the first embodiment includes a channel for switching broadcasting and is a receiving device mounted on a vehicle, and whether or not the deterioration is recovered when the broadcast quality is deteriorated. And the receiving channel is switched.

  The in-vehicle television device 1 generates a quality evaluation signal that evaluates deterioration of broadcast quality, which is broadcast quality, based on the time change of the radio wave intensity received on the channel, and instantaneously interrupts radio waves using the generated quality evaluation signal The broadcast quality deterioration due to the vehicle and the broadcast quality deterioration due to the movement of the vehicle are identified and the channel switching is controlled, so if the broadcast quality deteriorates, whether the deterioration recovers based on the time change of the radio field strength And the receiving channel can be switched.

  Regardless of analog broadcast or digital broadcast, the greatest cause of deterioration in broadcast quality is a decrease in the level of received radio wave intensity. Therefore, it is convenient if the level of the received radio wave intensity can be directly measured from the time change of the radio wave intensity of the reception channel of the analog tuner or digital tuner. However, since the frequency of the received radio wave is high, the DC component is detected in order to see the level change. There is a need to. Since the AGC detector detects the received radio wave amplified by the amplifier and outputs the AGC voltage for controlling the gain of the amplifier, in the first embodiment, the AGC voltage is used to identify the broadcast quality deterioration.

(2) Configuration of the In-Vehicle Television Device As shown in FIG. 1, the in-vehicle television device 1 includes antennas 2 and 4, an analog television receiver 20, a digital television receiver 40, an MPEG decoder 46, and quality evaluation signal generation circuits 30 and 50. , Main control unit 10, storage unit 11, display control unit 12, display 13, GPS receiver 14, vehicle speed sensor 15, and communication terminal device 16.

  The analog television receiver 20 is connected to the antenna 2 to receive an analog broadcast and output it to the display control unit 12. The digital television receiver 40 is connected to the antenna 4 to receive a digital broadcast and output it to the display control unit 12.

  The quality evaluation signal generation circuit 30 is a circuit that converts the AGC voltage output from the analog television receiver 20 and the change amount of the AGC voltage into a digital amount and outputs the digital amount to the main control unit 10. The quality evaluation signal generation circuit 50 is a circuit that converts the AGC voltage output from the digital television receiver 40 and the change amount of the AGC voltage into a digital amount and outputs the digital amount to the main control unit 10.

  The main control unit 10 is a control unit that performs overall control of the in-vehicle television device 1, and specifically includes a channel switching control unit 101, a vehicle position acquisition unit 102, an average value calculation unit 103, and a vehicle speed detection unit 104. The channel switching control unit 101 identifies broadcast quality degradation due to instantaneous interruption of radio waves and broadcast quality degradation due to vehicle movement according to the amount of time change in radio field intensity received by the analog television receiver 20 or the digital television receiver 40. Then, the display control unit 12 is controlled to control the switching of the video signal output from the analog television receiver 20 or the digital television receiver 40 or the switching of the channel of the analog television receiver 20 or the digital television receiver 40. It is a processing unit.

  The vehicle position acquisition unit 102 is a processing unit that acquires the position of the vehicle from the GPS receiver 14 or the communication terminal device 16. The average value calculation unit 103 is a processing unit that calculates the average value of the time change amount of the AGC voltage. The vehicle speed detection unit 104 is a processing unit that detects the speed of the vehicle using the vehicle speed sensor 15.

  The storage unit 11 is a memory such as a RAM, and includes a reception channel position correspondence table 111 and a reception channel distance correspondence table 112. The reception channel position correspondence table 111 is a table for storing channel identification information and reception time before the instantaneous interruption of the received radio wave in association with the vehicle position acquired by the vehicle position acquisition unit 102. When the vehicle returns to the previous position, data for searching the corresponding reception channel from the position of the vehicle is stored. The reception channel distance correspondence table 112 is a table associating the reception channels with the reception distances from the base station, and stores data for determining whether or not the vehicle is in the broadcast service reception area. Each reception channel has a different frequency. The higher the frequency of the radio wave, the greater the attenuation of the radio wave intensity, and the shorter the reception distance from the base station.

  The display control unit 12 switches the video signal output from the analog television receiver 20 or the digital television receiver 40 based on a request from the channel switching control unit 101, and identifies channel identification information and switching time regarding the received channel. Then, an image for generating switching information consisting of a response request as to whether or not to switch is displayed on the display 13. In addition, an image for displaying switching information for selecting and inputting a reception channel on the display 13 is generated.

  The display 13 is an output device that outputs a video signal from the analog television receiver 20 or the digital television receiver 40. Specifically, the display 13 is a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), or the like. . The GPS receiver 14 is a receiver that receives positioning information from GPS satellites. The vehicle speed sensor 15 is a sensor that measures the speed of the vehicle. The communication terminal device 16 is a terminal device that performs wireless communication, and acquires the current position of the vehicle, map information, and the like based on a request from the main control unit 10.

  The analog television receiver 20 includes an analog tuner 21, an IF detector 22, an IF amplifier 23, a demodulator 24, and an AGC detector 25 therein.

  The analog tuner 21 is a circuit that switches the radio wave received by the antenna to a channel designated by the channel switching control unit 101 and amplifies the radio wave at high frequency. The IF detector 22 is a frequency conversion circuit that converts a radio wave amplified by high frequency amplification by an analog tuner 21 to an intermediate frequency. The IF amplifier 23 is an amplifier that amplifies the radio wave frequency-converted by the IF detector 22. The demodulator 24 is a circuit that separates the carrier wave and the video signal from the received radio wave, extracts only the video signal, and amplifies the extracted video signal at a low frequency.

  The AGC detector 25 is a circuit that controls the level fluctuation of the intermediate frequency radio wave amplified by the IF amplifier 23. The AGC detector 25 outputs an AGC voltage to the IF amplifier 23, increases the gain of the IF amplifier 23 for weak received radio waves, and suppresses the gain of the IF amplifier 23 for strong received radio waves, thereby reducing the analog television receiver. 20 is controlled to be constant, and an AGC voltage is output to the quality evaluation signal generation circuit 30.

  The quality evaluation signal generation circuit 30 is a circuit that converts the AGC voltage and the absolute value of the change amount of the AGC voltage into a digital amount and outputs the digital amount to the main control unit 10. The quality evaluation signal generation circuit 30 includes a delay circuit 31, a subtractor 32, an ABS circuit 33, D / A converters 34 and 35 are provided.

  The delay circuit 31 is a circuit that delays the AGC voltage with time. The subtractor 32 is a circuit that takes the difference between the AGC voltage delayed by the delay circuit 31 and the AGC voltage that does not pass through the delay circuit 31. The ABS circuit 33 is a circuit that converts the difference in the AGC voltage output from the subtractor 32 into an absolute value. The D / A converter 34 is a circuit that converts the absolute value of the difference between the AGC voltages output from the ABS circuit 33 into a digital quantity. The D / A converter 35 converts the AGC voltage into a digital quantity. Circuit.

  The digital television receiver 40 includes a digital tuner 41, an IF detector 42, an IF amplifier 43, a demodulator 44, and an AGC detector 45 therein.

  The digital tuner 41 is a circuit that switches the radio wave received by the antenna to a channel designated by the channel switching control unit 101 and amplifies the radio wave at high frequency. The IF detector 42 is a frequency conversion circuit that converts a radio wave amplified by high frequency amplification to an intermediate frequency by the digital tuner 41. The IF amplifier 43 is an amplifier that amplifies the radio wave frequency-converted by the IF detector 42. The demodulator 44 is a circuit that separates the carrier wave and the video signal from the received radio wave, extracts only the video signal, and amplifies the extracted video signal at a low frequency. The MPEG decoder 46 is a device that decodes the compression-encoded video signal and outputs it to the display control unit 12.

  The AGC detector 45 is a circuit that controls the level fluctuation of the intermediate frequency radio wave amplified by the IF amplifier 43. The AGC detector 45 outputs an AGC voltage to the IF amplifier 43, increases the gain of the IF amplifier 43 for weak received radio waves, and suppresses the gain of the IF amplifier 43 for strong received radio waves, thereby reducing the gain of the digital television receiver. The output of 40 is controlled to be constant and the AGC voltage is output to the quality evaluation signal generation circuit 50.

  The quality evaluation signal generation circuit 50 is a circuit that converts the AGC voltage and the absolute value of the change amount of the AGC voltage into a digital amount and outputs the digital amount to the main control unit 10. The quality evaluation signal generation circuit 50 includes a delay circuit 51, a subtractor 52, an ABS circuit 53, D / A converters 54 and 55 are provided.

  The delay circuit 51 is a circuit that delays the AGC voltage with time. The subtractor 52 is a circuit that takes the difference between the AGC voltage delayed by the delay circuit 51 and the AGC voltage that does not pass through the delay circuit 51. The ABS circuit 53 is a circuit that converts the difference in the AGC voltage output from the subtractor 52 into an absolute value. The D / A converter 54 is a circuit that converts the absolute value of the difference between the AGC voltages output from the ABS circuit 53 into a digital quantity, and the D / A converter 55 converts the AGC voltage into a digital quantity. Circuit.

(3) Example of time change regarding received radio wave intensity, AGC voltage, and change amount of AGC voltage of in-vehicle TV device Next, referring to FIG. 2, changes in the received radio wave intensity, AGC voltage, and AGC voltage of the in-vehicle TV device 1 An example of the time change regarding the quantity will be described. FIG. 2 is a diagram illustrating an example of a time change regarding the received radio wave intensity, the AGC voltage, and the change amount of the AGC voltage of the in-vehicle television device 1. The level of the received radio wave intensity of the in-vehicle television device 1 in the mobile broadcast service area is given as a function of the height of the base station antenna, the height of the receive antenna, the frequency of the transmitted radio wave, and the distance from the base station. However, it is assumed here that the level of received radio wave intensity depends only on the distance from the base station. In addition, the received radio wave intensity is inversely proportional to the square of the distance from the base station, but FIG. 2 shows a qualitative tendency for the level of the received radio wave to decrease.

  As shown in FIG. 2, the level of the received radio wave intensity of the analog television receiver 20 or the digital television receiver 40 decreases as the vehicle moves away from the base station. In addition, when there is a shielding object that shields the received radio wave in the middle of traveling, and the vehicle is hidden by the shielding object, the level of the radio wave intensity of the in-vehicle television apparatus rapidly decreases, causing an instantaneous interruption of the received radio wave.

  In such a case, the AGC detectors 25 and 45 detect a decrease in the radio field intensity level, increase the gain of the IF amplifiers 23 and 43, and try to keep the output constant. Therefore, as shown in FIG. 2, the level of the AGC voltage output from the AGC detectors 25 and 45 gradually increases as the vehicle moves away from the base station. In addition, when the vehicle is hidden behind the shield and the level of the received radio wave suddenly decreases, the AGC voltage increases rapidly. When the vehicle exits the shield and the level of the received radio wave is restored, the AGC voltage is It descends rapidly.

  Further, the quality evaluation signal generation circuits 30 and 50 are digital quantities of the absolute value of the difference between the AGC voltage output from the AGC detectors 25 and 45 and the AGC voltage converted from the AGC voltage, that is, the change amount of the AGC voltage. Is output to the main control unit 10. Therefore, as shown in FIG. 2, the amount of change in the AGC voltage output from the quality evaluation signal generation circuits 30 and 50 keeps a value less than the first threshold while the vehicle moves away from the base station. Further, the amount of change in the AGC voltage is the first when the vehicle is hidden behind the shield and the level of the received radio wave intensity suddenly decreases and when the vehicle exits the shield and the level of the received radio wave intensity returns to the original level. A peak exceeding the threshold value is formed.

  As shown in the figure, when the change amount of the AGC voltage becomes equal to or greater than the first threshold value, it can be determined that the received radio wave is temporarily interrupted because the vehicle is hidden by the shield. Accordingly, when the amount of change in the AGC voltage becomes equal to or greater than the first threshold, the degradation of the image quality is recovered and the reception channel is held. However, when the AGC voltage is equal to or higher than the second threshold, that is, when the instantaneous interruption of the received radio wave continues for the first predetermined switching time, for example, when entering a long tunnel, the reception channel is switched.

  Here, the first threshold value and the second threshold value are set as the amount of change in the AGC voltage and the value of the AGC voltage when the deterioration in broadcast quality cannot withstand viewing due to a decrease in the level of received radio wave intensity. In addition, the first predetermined switching time is a momentary interruption of received radio waves such that the vehicle enters the shadow of the shielding object while traveling, or stops behind the shielding object while waiting for a signal and starts immediately. This is a setting value for distinguishing between a case where it ends in a short time and a case where the vehicle enters a long tunnel and the instantaneous interruption of the received radio wave continues.

  Further, when the amount of change in the AGC voltage is less than the first threshold and the state where the AGC voltage is increasing continues for a second predetermined switching time or more, the level of the received radio wave intensity is reduced due to the movement of the vehicle, Since the deterioration of the image quality is not recovered, the reception channel is switched.

  Here, the second predetermined switching time is a crossing time for traversing the mobile broadcast service area at the upper limit of the traveling speed of the vehicle, for example, the traveling speed of the road. The second predetermined switching time depends on the traveling speed of the vehicle and the size of the service area. In addition, the size of a mobile broadcast service area is determined by the reception distance of radio waves. Further, the reception distance of radio waves depends on the frequency of radio waves. That is, the higher the frequency, the greater the attenuation of radio waves, so the reception distance becomes narrower. Therefore, the second predetermined switching time is changed in consideration of the positional relationship of the vehicle in the service area according to the traveling speed of the vehicle and the frequency of the reception channel.

  As described above, since the AGC voltage and the change amount of the AGC voltage correspond to the time change of the reception radio wave intensity of the analog television receiver 20 or the digital television receiver 40, it is based on the change amount of the AGC voltage and the AGC voltage. It is possible to identify the broadcast quality deterioration due to the instantaneous interruption of radio waves and the broadcast quality deterioration due to movement of the vehicle, and to switch the reception channel.

  As described above, the quality evaluation signal generation circuits 30 and 50 generate the quality evaluation signal for evaluating the deterioration of the broadcast quality, which is the broadcast quality, based on the time change of the radio wave intensity received by the channel, and the channel switching control unit 101 uses the generated quality evaluation signal to identify broadcast quality deterioration due to instantaneous interruption of radio waves and broadcast quality deterioration due to movement of a moving object, and to control channel switching. In this case, it is possible to switch the reception channel by identifying whether or not the deterioration is recovered based on the time change of the reception radio wave intensity.

  Further, since the quality evaluation signal generation circuits 30 and 50 generate the quality evaluation signal using the AGC voltage for performing control with respect to the time change of the radio wave intensity, when the broadcast quality is deteriorated, the time of the AGC voltage is determined. Based on the change, the reception channel can be switched by identifying whether or not the deterioration is recovered.

  Further, when the time change amount of the AGC voltage increases to the first threshold value or more, the channel switching control unit 101 determines that the broadcast quality is deteriorated due to the instantaneous interruption of the radio wave, holds the reception channel, and the time change amount is If the state where the AGC voltage is equal to or higher than the second threshold continues for the first predetermined switching time or more after the increase to the first threshold or higher, the reception channel is changed even if the broadcast quality is deteriorated due to instantaneous interruption of radio waves. Since the switching is performed, if the deterioration of the broadcast quality due to the instantaneous interruption of the radio wave is temporary, the reception channel can be maintained without being switched as the deterioration of the broadcast quality is recovered.

  Further, the channel switching control unit 101 switches the reception channel when the time change amount of the AGC voltage is less than the first threshold and the state where the AGC voltage is rising continues for the second predetermined switching time or longer. Therefore, it is possible to switch the reception channel on the assumption that the broadcast quality is deteriorated due to the movement of the vehicle.

  In addition, since the vehicle position acquisition unit 102 that acquires the position of the vehicle and the reception channel position correspondence table 111 that stores the reception channel identification information and the reception time in association with the vehicle position are further provided, the channel When the switching control unit 101 holds the reception channel, the identification information and the reception time of the reception channel before the time change amount of the AGC voltage increases to the first threshold value or more are received by the vehicle position acquisition unit 102. The received channel position corresponding table 111 is stored in association with the position, and when the vehicle position is returned from outside the received area to the stored vehicle position, the received channel is searched from the received channel position corresponding table 111. It is also possible to return to the reception channel. Or it can return to the reception channel of the stored reception time.

  Further, the channel switching control unit 101 detects N times that the time change amount of the AGC voltage is less than the first threshold and the state where the AGC voltage is increasing continues for the second predetermined switching time or more. In this case, since the reception channel is switched, the channel switching control unit 101 can accurately determine whether or not the vehicle is outside the reception area.

  In addition, since the average value calculation unit 103 that calculates the average value of the time change amount of the AGC voltage is further provided, the channel switching control unit 101 determines the time change amount of the AGC voltage calculated by the average value calculation unit 103. When the average value is less than the first threshold and the state where the AGC voltage is rising continues for the second predetermined switching time or more, the reception channel is switched. Therefore, the channel switching control unit 101 can accurately determine whether or not the vehicle is outside the reception area.

  Further, since the vehicle speed detection unit 104 that detects the vehicle speed is provided, the channel switching control unit 101 changes the second predetermined switching time in association with the vehicle speed detected by the vehicle speed detection unit 104. can do. Therefore, by changing the elapsed time according to the speed of the vehicle, it is possible to accurately determine the time from the moving distance to the outside of the reception area.

  In addition, since the reception channel distance correspondence table 112 that stores the reception channel and the reception distance from the base station in association with each other is further provided, the channel switching control unit 101 corresponds to the correspondence stored in the reception channel distance correspondence table 112. The second predetermined switching time can be changed in association with the receiving channel. Therefore, by changing the elapsed time according to the reception distance of the corresponding channel, it is possible to accurately determine the time from the moving distance to the outside of the reception area.

(4) Example of Display Image of Switching Information Next, an example of a display image of switching information generated by the display control unit 12 of the in-vehicle television device 1 will be described with reference to FIGS. FIG. 3 is a diagram illustrating an example of a display image of switching information generated by the display control unit 12 of the in-vehicle television device 1. FIG. 4 is a diagram illustrating another example of the display image of the switching information generated by the display control unit 12 of the in-vehicle television device 1. FIG. 5 is a diagram illustrating still another example of the display image of the switching information generated by the display control unit 12 of the in-vehicle television device 1.

  When switching the reception channel, the channel switching control unit 101 requests the display control unit 12 to display the switching information “switch to yych after xx seconds” on the display 13, and the display control unit 12 As shown, the switching information is displayed on the display 13.

  Thereafter, as shown in FIG. 4, the display control unit 12 displays a confirmation message “Can I change to yych? YES / NO” on the display 13 after zz seconds. When the user clicks “YES”, the channel switching control unit 101 receives a response via the display control unit 12 and switches to yych. When the user clicks “NO”, the channel switching control unit 101 switches the channel. Do not do. Alternatively, the channel switching control unit 101 automatically switches to yych when the user does not click “YES” or “NO” for cc seconds. Alternatively, it is possible not to switch.

  Further, when switching the reception channel, the channel switching control unit 101 requests the display control unit 12 to display switching information as shown in FIG. As shown in the figure, a switching channel can be selected by clicking an analog / digital tuner switching button 201, a channel up / down button 202, and a channel search up / down button 203. By clicking on the analog / digital television receiver display 204 and the channel display 205, the receiver or channel to be switched is established. The channel switching control unit 101 receives a response via the display control unit 12 and switches the reception channel.

  As described above, when switching the reception channel, the channel switching control unit 101 causes the display 13 to display the switched channel identification information and the switching information including the switching time on the reception channel, so that the user-friendly television image display is performed. Is possible.

  In addition, when switching the reception channel, the channel switching control unit 101 displays the switching information including the identification information of the channel after the switching related to the reception channel, the switching time, and the response request whether to switch or not on the display 13. TV image display becomes possible.

  In addition, since the channel switching control unit 101 switches the reception channel according to the response to the switching information from the display 13, a user-friendly TV image display is possible.

  Further, when switching the receiving channel, the channel switching control unit 101 displays switching information for selecting and receiving the receiving channel on the display 13 and switches to the receiving channel selected and input in the switching information, so that a user-friendly TV image display is performed. It becomes possible.

(5) Channel switching control procedure for identifying deterioration in broadcast quality due to instantaneous interruption of radio waves and deterioration in broadcast quality due to vehicle movement Next, referring to FIG. A channel switching control procedure for identifying broadcast quality deterioration and broadcast quality deterioration due to vehicle movement will be described. FIG. 6 is a flowchart showing a channel switching control procedure in the case where the in-vehicle television device 1 identifies broadcast quality degradation due to instantaneous interruption of radio waves and broadcast quality degradation due to vehicle movement.

  As shown in the figure, the quality evaluation signal generation circuits 30 and 50 generate the amount of change in the AGC voltage using the AGC voltage output from the AGC detectors 25 and 45, and the channel switching control unit 101 receives the AGC voltage and the AGC voltage. A change amount of the AGC voltage is output (step S601). Then, the channel switching control unit 101 checks whether or not the amount of change in the AGC voltage is greater than or equal to the first threshold (Step S602). As a result, when the amount of change in the AGC voltage is equal to or greater than the first threshold (Yes in step S602), the channel switching control unit 101 further determines that the state where the AGC voltage is equal to or greater than the second threshold is the first predetermined value. It is checked whether or not the switching time is continued (step S603).

  As a result, when the state where the AGC voltage is equal to or higher than the second threshold does not continue for the first predetermined switching time or longer (No in step S603), the channel switching control unit 101 holds the reception channel as it is, End the procedure. On the other hand, when the state where the AGC voltage is equal to or higher than the second threshold continues for the first predetermined switching time or longer (Yes in step S603), the channel switching control unit 101 requests display of switching information of the reception channel. (Step S604).

  Then, the display 13 displays switching information as shown in FIGS. 3 to 5 (step S605). Further, the channel switching control unit 101 receives a response from the user to the switching information shown in FIG. 4 or 5 (step S606), and switches the reception channel according to the response (step S607).

  On the other hand, when the change amount of the AGC voltage is less than the first threshold (No at Step S602), the channel switching control unit 101 further checks whether the AGC voltage is increasing (Step S608). . As a result, when the AGC voltage has not increased (No at Step S608), the channel switching control unit 101 holds the reception channel and ends this procedure.

  On the other hand, if the AGC voltage is increasing (Yes at step S608), the channel switching control unit 101 further checks whether the increase in the AGC voltage continues for a second predetermined switching time (step S609). ). As a result, when the increase in the AGC voltage does not continue for the second predetermined switching time or longer (No in step S609), the channel switching control unit 101 holds the reception channel and ends this procedure. On the other hand, when the increase in the AGC voltage continues for the second predetermined switching time or more (Yes in step S609), the channel switching control unit 101 performs the procedure from step S604 to step S607.

  As described above, since the quality evaluation signal generation circuits 30 and 50 generate the quality evaluation signal using the AGC voltage for controlling the time variation of the radio field intensity, when the broadcast quality deteriorates, the AGC The reception channel can be switched by identifying whether or not the deterioration is recovered based on the time change of the voltage.

  Further, the channel switching control unit 101 holds the reception channel when the time change amount of the AGC voltage increases to the first threshold value or more, and after the time change amount increases to the first threshold value or more, the AGC voltage is changed to the first value. When the state equal to or greater than the threshold of 2 continues for the first predetermined switching time or longer, the reception channel is switched. Therefore, if the deterioration of the broadcast quality due to the instantaneous interruption of the radio wave is temporary, the deterioration of the broadcast quality. Can be maintained without switching the receiving channel.

  Further, the channel switching control unit 101 switches the reception channel when the time change amount of the AGC voltage is less than the first threshold and the state where the AGC voltage is rising continues for the second predetermined switching time or longer. Therefore, it is possible to switch the reception channel on the assumption that the broadcast quality is deteriorated due to the movement of the vehicle.

(6) Channel switching control procedure for storing vehicle position, reception time, and reception channel before instantaneous interruption of received radio wave Next, referring to FIG. A channel switching control procedure when storing the position, reception time, and reception channel will be described. FIG. 7 is a flowchart showing a channel switching control procedure in the case where the vehicle position, the reception time, and the reception channel before the instantaneous interruption of the received radio wave are stored in the in-vehicle television device 1. Since the difference from the channel switching control procedure of FIG. 6 is step S704 to step S705, step S704 to step S705 will be described.

  The vehicle position acquisition unit 102 acquires the position of the vehicle from the positioning information or map information received using the GPS receiver 14 or the communication terminal device 16 (step S704). Then, the reception channel identification information and the reception time are stored in the reception channel position correspondence table 111 in association with the position of the vehicle (step S705).

  As described above, the vehicle position acquisition unit 102 that acquires the position of the vehicle and the reception channel position correspondence table 111 that stores the reception channel identification information and the reception time in association with the vehicle position are further provided. Therefore, when the channel switching control unit 101 holds the reception channel, the vehicle position acquisition unit 102 acquires the reception channel identification information and the reception time before the time change amount of the AGC voltage increases to the first threshold value or more. The received channel position is stored in the reception channel position correspondence table 111 in association with the position of the vehicle, and when the vehicle position is returned from outside the reception area to the stored vehicle position in the reception area, the reception channel is determined from the reception channel position correspondence table 111. You can search and return to the receiving channel. Alternatively, it is possible to return to the reception channel having the stored reception time.

(7) Channel switching control procedure for confirming deterioration of broadcast quality due to movement of vehicle a plurality of times Next, referring to FIG. 8, in-vehicle television apparatus 1 confirms the deterioration of broadcast quality due to movement of the vehicle a plurality of times. A channel switching control procedure in this case will be described. FIG. 8 is a flowchart showing a channel switching control procedure in the case where the in-vehicle television apparatus 1 confirms a plurality of times broadcast quality deterioration due to vehicle movement. Since the difference from the channel switching control procedure of FIG. 6 is step S809, step S809 will be described.

  The channel switching control unit 101 confirms whether the increase in AGC voltage has continued N times after the second predetermined switching time (step S809). As a result, when the increase in the AGC voltage has not continued N times after the second predetermined switching time (No at Step S809), the channel switching control unit 101 holds the reception channel and ends this procedure. On the other hand, when the increase in the AGC voltage continues N times after the second predetermined switching time (Yes at Step S809), the procedure from Step S804 to Step S807 is executed.

  As described above, the channel switching control unit 101 determines that the time change amount of the AGC voltage is less than the first threshold and the state where the AGC voltage is increasing continues for the second predetermined switching time or more. Since the reception channel is switched when detected N times, the channel switching control unit 101 can accurately determine whether or not the vehicle is outside the reception area.

(8) Channel switching control procedure for confirming deterioration of broadcast quality due to vehicle movement based on time average value of change amount of AGC voltage Next, referring to FIG. A channel switching control procedure for confirming deterioration of broadcast quality due to vehicle movement based on the time average value of the change amount will be described. FIG. 9 is a flowchart showing a channel switching control procedure in the case where confirmation of broadcast quality deterioration due to vehicle movement is confirmed based on the time average value of the change amount of the AGC voltage in the in-vehicle television device 1. Since the difference from the channel switching control procedure of FIG. 6 is step S908, step S908 will be described.

  When the change amount of the AGC voltage is less than the first threshold (No at Step S902), the average value calculation unit 103 calculates the time average of the change amount of the AGC voltage (Step S908). Then, the channel switching control unit 101 checks whether or not the AGC voltage is increased by using the time average of the change amount of the AGC voltage calculated by the average value calculation unit 103 (step S909).

  As described above, since the average value calculation unit 103 that calculates the average value of the time change amount of the AGC voltage is further provided, the channel switching control unit 101 determines the time of the AGC voltage calculated by the average value calculation unit 103. When the average value of the amount of change is less than the first threshold and the state where the AGC voltage is increasing continues for the second predetermined switching time or more, the reception channel is switched. Therefore, the channel switching control unit 101 can accurately determine whether or not the vehicle is outside the reception area.

(9) Channel Switching Control Procedure for Changing Reception Channel Switching Time According to Vehicle Speed Next, referring to FIG. 10, the in-vehicle television device 1 changes the reception channel switching time according to the vehicle speed. A channel switching control procedure in this case will be described. FIG. 10 is a flowchart showing a channel switching control procedure when the switching time of the receiving channel is changed in accordance with the vehicle speed in the in-vehicle television device 1. Since the difference from the channel switching control procedure in FIG. 6 is Steps S1009 to S1010, Steps S1009 to S1010 will be described.

  When the AGC voltage is increasing (Yes at Step S1008), the vehicle speed detection unit 104 acquires vehicle speed data using the vehicle speed sensor (Step S1009). Then, the channel switching control unit 101 changes the second predetermined switching time according to the vehicle speed detected by the vehicle speed detection unit 104 (step S1010). Further, the channel switching control unit 101 checks whether or not the increase in the AGC voltage continues for the second predetermined switching time or more (step S1011).

  As described above, since the vehicle speed detection unit 104 that detects the vehicle speed is provided, the channel switching control unit 101 performs the second predetermined switching in association with the vehicle speed detected by the vehicle speed detection unit 104. You can change the time. Therefore, by changing the elapsed time according to the speed of the vehicle, it is possible to accurately determine the time from the moving distance to the outside of the reception area.

(10) Channel Switching Control Procedure for Changing Switching Time According to Reception Channel Next, referring to FIG. 11, a channel switching control procedure for changing the switching time according to the reception channel in the in-vehicle television device 1. Will be described. FIG. 11 is a flowchart showing a channel switching control procedure when the switching time is changed according to the reception channel in the in-vehicle television device 1. Since the difference from the channel switching control procedure of FIG. 6 is step S1109 to step S1110, step S1109 to step S1110 will be described.

  When the AGC voltage is increasing (Yes at Step S1108), the channel switching control unit 101 acquires the reception distance of the corresponding channel from the transmission / reception channel distance correspondence table 112 (Step S1109). Then, the channel switching control unit 101 changes the second predetermined switching time according to the acquired reception distance of the channel (step S1110). Further, the channel switching control unit 101 checks whether or not the increase in the AGC voltage continues for the second predetermined switching time or more (step S1111).

  As described above, since the reception channel distance correspondence table 112 that stores the reception channel and the reception distance in association with each other is further provided, the channel switching control unit 101 corresponds to the corresponding stored in the reception channel distance correspondence table 112. The second predetermined switching time can be changed in association with the reception channel. Therefore, by changing the elapsed time according to the reception distance of the corresponding channel, it is possible to accurately determine the time from the moving distance to the outside of the reception area.

  By the way, in the in-vehicle television device 1 according to the first embodiment, the case where the AGC detectors 25 and 45 control the level fluctuation of the intermediate frequency radio wave amplified by the IF amplifiers 23 and 43 has been described. , 41 can also be applied to control the level fluctuation of the radio wave amplified at high frequency. In the in-vehicle television apparatus according to the second embodiment, a case where the AGC detector controls the level fluctuation of the radio wave amplified by the analog / digital tuners 21 and 41 will be described.

  First, the configuration of the in-vehicle television device 1a according to the second embodiment will be described with reference to FIG. FIG. 12 is a functional block diagram illustrating the configuration of the in-vehicle television device 1a according to the second embodiment. As shown in the figure, since the AGC detectors 25a and 45a are different from the functional block diagram of the first embodiment shown in FIG. 1, the AGC detectors 25a and 45a will be described.

  The analog tuner 21 is a circuit that switches the radio wave received by the antenna to a channel designated by the channel switching control unit 101 and amplifies the radio wave at high frequency. The AGC detector 25 a outputs an AGC voltage that controls the level of the radio wave amplified by the analog tuner 21 to the analog tuner 21 and the quality evaluation signal generation circuit 30.

  The digital tuner 41 is a circuit that switches the radio wave received by the antenna to a channel designated by the channel switching control unit 101 and amplifies the radio wave at high frequency. The AGC detector 45 a outputs an AGC voltage that controls the level of the radio wave amplified by the digital tuner 41 to the digital tuner 41 and the quality evaluation signal generation circuit 50.

  As described above, in the in-vehicle television device 1a according to the second embodiment, the AGC detectors 25a and 45a control the levels of the radio waves amplified by the analog tuner 21 and the digital tuner 41, respectively, according to the first embodiment. It is different from the in-vehicle television device 1. A processing procedure for identifying deterioration in broadcast quality due to instantaneous interruption of radio waves and deterioration in broadcast quality due to vehicle movement based on the AGC voltage output from the AGC detectors 25a and 45a and the amount of change in the AGC voltage is described in the on-vehicle system according to the first embodiment. This is exactly the same as the television device 1. Therefore, when the broadcast quality deteriorates, the in-vehicle television device 1a according to the second embodiment can switch the reception channel by identifying whether or not the deterioration is recovered based on the time change of the AGC voltage.

  As described above, the receiving apparatus according to the present invention is useful for a broadcast receiving apparatus mounted on a mobile body, and is particularly suitable for a broadcast receiving apparatus mounted on a vehicle.

1 is a functional block diagram illustrating a configuration of a receiving device according to a first embodiment. It is a figure which shows an example of the time change regarding the received radio wave strength of an in-vehicle television apparatus, an AGC voltage, and the variation | change_quantity of an AGC voltage. It is a figure which shows an example of the display image of the switching information which the display control part of a vehicle-mounted television apparatus produces | generates. It is a figure which shows another example of the display image of the switching information which the display control part of a vehicle-mounted television apparatus produces | generates. It is a figure which shows another example of the display image of the switching information which the display control part of a vehicle-mounted television apparatus produces | generates. It is a flowchart which shows the channel switching control procedure in the case of identifying degradation of broadcast quality due to instantaneous interruption of radio waves and degradation of broadcast quality due to vehicle movement in the in-vehicle television device. It is a flowchart which shows the channel switching control procedure in the case of memorize | storing the vehicle position before the momentary interruption of a received radio wave, reception time, and a receiving channel in a vehicle-mounted television apparatus. It is a flowchart which shows the channel switching control procedure in the case of confirming deterioration of the broadcast quality by movement of a vehicle in multiple times in a vehicle-mounted television apparatus. It is a flowchart which shows the channel switching control procedure in the case of confirming deterioration of the broadcast quality by movement of a vehicle based on the time average value of AGC variation | change_quantity in a vehicle-mounted television apparatus. It is a flowchart which shows the channel switching control procedure in the case of changing the switching time of a receiving channel according to vehicle speed in a vehicle-mounted television apparatus. It is a flowchart which shows the channel switching control procedure in the case of changing switching time according to a receiving channel in a vehicle-mounted television apparatus. It is a functional block diagram which shows the structure of the vehicle-mounted television apparatus which concerns on the present Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a Car-mounted television apparatus 2,4 Antenna 10 Main control part 11 Memory | storage part 12 Display control part 13 Display 14 GPS receiver 15 Vehicle speed sensor 16 Communication terminal device 20, 20a Analog television receiver 21 Analog tuner 22 IF detector 23 IF Amplifier 24 Demodulator 25, 25a AGC detector 30, 50 Quality evaluation signal generation circuit 31, 51 Delay circuit 32, 52 Subtractor 33, 53 ABS circuit 34, 35, 54, 55 D / A converter 40, 40a Digital television Receiver 41 Digital tuner 42 IF detector 43 IF amplifier 44 Demodulator 45, 45a AGC detector 46 MPEG decoder 101 Channel switching controller 102 Vehicle position acquisition unit 103 Average value calculation unit 104 Vehicle speed detection unit 111 Reception channel position correspondence table 112 Receive channel Le distance corresponding table 201 analog / digital tuner switch button 202 channel up / down button 203 channel search up / down buttons 204 analog / digital television receiver display 205 channel display

Claims (4)

A receiving device having a channel selection unit for switching broadcasts to be received,
Channel switching control means for controlling switching of the receiving broadcast station by the channel selection unit based on the radio field intensity of the broadcast signal selected by the channel selection unit;
Broadcast information display means for displaying information related to the broadcast received when the received broadcast is switched when the channel selection switching condition in the channel switching control means is satisfied;
A receiving apparatus comprising: A receiving device having a channel selection unit for switching broadcasts to be received,
Channel switching control means for controlling switching of the receiving broadcast station by the channel selection unit based on the radio field intensity of the broadcast signal selected by the channel selection unit;
A response request display means for displaying a response request as to whether or not to switch the received broadcast when a channel selection switching condition is established in the channel switching control means;
The channel switching control means controls switching of a receiving broadcast station by the channel selection unit based on a response to the response request.   The receiving apparatus according to claim 2, wherein when a response is not made to the response request for a predetermined time, switching of a receiving broadcast station by the channel selection unit is executed. A receiving device having a channel selection unit for switching broadcasts to be received,
Channel switching control means for controlling switching of the receiving broadcast station by the channel selection unit based on the radio wave intensity in the broadcast signal of the broadcast selected by the channel selection unit,
When the channel selection switching condition in the channel switching control means is satisfied, it has switching information input means for inputting information about the received broadcast,
The channel information is based on the received broadcast information input by the switching information input means, and controls switching of the channel selection unit.

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