JP2006279450A - On-vehicle digital television receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle digital television receiver for preventing fluctuation in antenna switching even when an automobile is running in higher velocity and thereby assuring excellent receiving performance. <P>SOLUTION: The on-vehicle digital television receiver 1 comprises a switching circuit 12 for selecting a desired receiving antenna from a plurality of receiving antennas 11, a microcomputer 18 for controlling the switching circuit to switch and select the receiving antenna of excellent receiving sensitivity to receive the signals, and a velocity detecting unit 16 for detecting the running velocity of an automobile. The microcomputer sets a switching interval of the switching circuit to a longer period in accordance with the running velocity when the velocity of automobile detected by the velocity detecting unit becomes higher. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-vehicle digital television receiver having a diversity function for switching and selecting a reception antenna with good reception sensitivity among a plurality of reception antennas, for example.

  Conventionally, as an in-vehicle television receiver having such a diversity function, a diversity function for switching and selecting a reception antenna having a good reception sensitivity among a plurality of reception antennas is provided, and reception is performed according to the moving speed of the vehicle. The antenna switching frequency is changed. For example, when the vehicle speed is 80 km / h or more, the switching frequency is 1/60 second cycle, and when the vehicle speed is 40 km / h or more and less than 80 km / h, the switching frequency is 1/30. In the case of a second cycle and a vehicle speed of 40 km / h or less, a 1/15 second cycle is set (see, for example, Patent Document 1).

  According to Patent Document 1, since the antenna switching frequency is increased as the moving speed of the vehicle is higher, a high-quality image can be obtained regardless of the moving state of the vehicle.

Also, in recent digital television receivers for in-vehicle use, a receiving antenna with good reception sensitivity is switched and selected based on AGC information and bit error rate (hereinafter simply referred to as BER) information obtained from an OFDM demodulation circuit. I have to.
Japanese Patent Laid-Open No. 6-204930 (see abstract and FIG. 1)

  However, according to the above-described conventional in-vehicle digital television receiver, the higher the moving speed of the vehicle, the higher the antenna switching frequency, that is, the shorter the antenna switching interval. For example, the calculation speed of digital demodulation in the OFDM demodulator circuit cannot be fully supported, and the antenna switching pull-in performance cannot follow the ever-changing reception situation, resulting in antenna switching fluctuations. As a result, reception performance may be degraded.

  The present invention has been made in view of the above points, and an object of the present invention is to prevent inconsistencies in antenna switching even when the moving speed of the vehicle increases, and as a result, to improve the reception performance. It is to provide a digital television receiver.

  In order to achieve the above object, an in-vehicle digital television receiver according to the present invention includes an antenna selecting means for selecting an arbitrary receiving antenna from among a plurality of receiving antennas, and receiving sensitivity among the plurality of receiving antennas. A vehicle-mounted digital television receiver having a control means for controlling the antenna selection means so as to switch and select a reception antenna for receiving a good reception signal, a movement speed detection means for detecting the movement speed of the vehicle; When the moving speed detected by the moving speed detecting means is increased, the antenna selecting means has a switching interval setting means for setting a long switching interval for switching and selecting the receiving antenna according to the moving speed. did.

  The on-vehicle digital television receiver of the present invention also includes an antenna selection means for selecting an arbitrary reception antenna from among a plurality of reception antennas, and a reception signal having a good reception sensitivity among the plurality of reception antennas. A vehicle-mounted digital television receiver having control means for controlling the antenna selection means to switch and select a receiving antenna to be received, the moving speed detecting means for detecting the moving speed of the vehicle, and the moving speed detecting means When the moving speed detected in (2) is less than a predetermined speed, a switching interval for switching and selecting the receiving antenna by the antenna selecting means is set to a predetermined interval, and when the moving speed is equal to or higher than the predetermined speed, the switching interval is set. And switching interval setting means for setting longer than the predetermined interval.

  According to the in-vehicle digital television receiver of the present invention configured as described above, when the moving speed of the vehicle increases, the switching interval for switching and selecting the receiving antenna is set by the antenna selecting means according to the moving speed. As a result, even if the moving speed of the vehicle increases, the antenna switching pull-in performance can be tracked against the changing reception conditions by reducing the frequency of antenna switching, thus preventing antenna switching fluctuations. As a result, the reception performance can be improved.

  In addition, according to the in-vehicle digital television receiver of the present invention, when the moving speed of the vehicle becomes less than the predetermined speed, the switching interval for switching and selecting the receiving antenna by the antenna selecting means is set to the predetermined interval, and the movement of the vehicle When the speed exceeds the predetermined speed, the switching interval is set longer than the predetermined interval, so even if the moving speed of the vehicle increases, the antenna switching frequency is reduced, so that Since the antenna switching pull-in performance can be followed, the antenna switching flutter can be prevented, and as a result, the reception performance can be improved.

  Hereinafter, an in-vehicle digital television receiving apparatus showing an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a schematic configuration inside a vehicle-mounted digital television receiver showing the first embodiment.

  An in-vehicle digital television receiver 1 shown in FIG. 1 includes a plurality (n) of reception antennas 11, a switching circuit 12 that switches and selects an arbitrary reception antenna 11 among the plurality of reception antennas 11, and a reception antenna 11. A tuner circuit 13 that tunes and receives a broadcast signal of a digital television broadcast, an OFDM demodulator circuit 14 that performs OFDM demodulation processing on the broadcast signal that is tuned and received by the tuner circuit 13, and MPEG processing the demodulated output of the OFDM demodulator circuit 14 The MPEG circuit 15 for outputting video / audio, the vehicle speed detecting unit 16 for detecting the moving speed of the vehicle by speed pulses, the memory unit 17 for storing various information, and the on-vehicle digital television receiver 1 as a whole And a microcomputer 18 for controlling. The antenna selection means corresponds to the switching circuit 12, the control means and the switching interval setting means correspond to the microcomputer 18, and the moving speed detection means corresponds to the vehicle speed detection unit 16.

  The OFDM demodulator circuit 14 includes an A / D converter 14A that digitally converts the broadcast signal tuned and received by the tuner circuit 13, an OFDM demodulator 14B that performs OFDM demodulation processing on the A / D converted broadcast signal, and the OFDM demodulator 14B. An error correction unit 14C that performs error correction processing on the demodulated output of the demodulation unit 14B.

  Further, the microcomputer 18 extracts the AGC information and the BER information of the received signal via the receiving antenna 11 in the OFDM demodulating circuit 14, and based on the extraction result, among the plurality of receiving antennas 11, reception with good reception sensitivity is performed. The switching circuit 12 is controlled by outputting a switching control signal so that the antenna 11 can be switched.

  FIG. 2 is an explanatory diagram showing the relationship between the moving speed V and the antenna switching interval Δt related to the in-vehicle digital television receiver 1 according to the first embodiment.

  As shown in FIG. 2, the memory unit 17 stores and manages the moving speed V and the antenna switching interval Δt corresponding to the moving speed V. Note that if the interval is too long, the antenna switching pull-in performance cannot follow the changing reception situation, and if the interval is too short, the digital demodulation calculation speed cannot be supported. Therefore, it is assumed that storage management is performed in association with the moving speed in consideration of these points.

  When the microcomputer 18 detects the current moving speed through the vehicle speed detecting unit 16, the microcomputer 18 reads the antenna switching interval Δt corresponding to the moving speed V from the memory unit 17, and sets the read antenna switching interval Δt.

  The microcomputer 18 controls reception antenna switching selection of the switching circuit 12 based on the antenna switching interval Δt being set.

  Therefore, according to the first embodiment, when the vehicle speed detection unit 16 detects the moving speed of the vehicle, the antenna switching interval Δt is read according to the moving speed V, and the switching circuit 12 is based on the antenna switching interval Δt. If the receiving antenna switching selection is controlled, that is, if the moving speed V is increased, the antenna switching interval Δt is increased compared to the conventional case, and the antenna switching pull-in performance is improved with respect to the changing reception situation. Since it is possible to follow, it is possible to prevent fluctuations in antenna switching, and as a result, it is possible to improve reception performance.

  In the first embodiment, the antenna switching interval Δt is set to be longer according to the moving speed of the vehicle as shown in FIG. 2, but may be described as follows. This embodiment will be described as a second embodiment. The same components as those in the in-vehicle digital television receiver 1 shown in FIG. 1 are denoted by the same reference numerals, and the description of the overlapping configuration and operation is omitted.

(Embodiment 2)
FIG. 3 is an explanatory diagram showing the relationship between the moving speed V and the antenna switching interval Δt according to the second embodiment.

  As shown in FIG. 3, the memory unit 17 stores and manages the moving speed V and the first antenna switching interval Δt1 and the second antenna switching interval Δt2 according to the moving speed V. Note that if the interval is too long, the antenna switching pull-in performance cannot follow the changing reception situation, and if the interval is too short, the digital demodulation calculation speed cannot be supported. Therefore, it is assumed that storage management is performed in association with the moving speed in consideration of these points.

  The microcomputer 18 detects the moving speed at the vehicle speed detecting unit 16 and, when it is determined that the moving speed is less than the predetermined speed VA, reads the first antenna switching interval Δt1 from the memory unit 17 and switches the first antenna switching. In addition to setting the interval Δt1, when it is determined that the moving speed is equal to or higher than the predetermined speed VA, the second antenna switching interval Δt2 is read from the memory unit 17 and the second antenna switching interval Δt2 is set.

  The microcomputer 18 controls reception antenna switching selection of the switching circuit 12 based on the antenna switching interval Δt being set.

  Therefore, according to the second embodiment, when the vehicle speed detection unit 16 detects the moving speed of the vehicle and determines that the moving speed is less than the predetermined speed VA, the first antenna switching interval Δt1 is set. At the same time, when it is determined that the moving speed is equal to or higher than the predetermined speed VA, the second antenna switching interval Δt2 is set. That is, when the moving speed becomes faster, the antenna switching interval Δt is made longer than the conventional one. Thus, since the antenna switching pull-in performance can follow the changing reception situation, the antenna switching fluctuation can be prevented, and as a result, the reception performance can be improved.

  In the in-vehicle digital television receiver according to the present invention, when the moving speed of the vehicle increases, the switching interval for selecting the receiving antenna by the antenna selecting means is set longer according to the moving speed. Even if the speed increases, by reducing the antenna switching frequency, the antenna switching pull-in performance can follow the changing reception situation, thus preventing the antenna switching flickering, resulting in good reception performance. Therefore, it is useful not only for vehicles but also for digital television receivers mounted on various mobile objects.

It is a block diagram which shows schematic structure inside the vehicle-mounted digital television receiver which shows the 1st Embodiment of this invention. It is explanatory drawing which shows the relationship between the moving speed in connection with 1st Embodiment, and an antenna switching space | interval. It is explanatory drawing which shows the relationship between the moving speed in connection with 2nd Embodiment, and an antenna switching space | interval.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 In-vehicle digital television receiver 11 Receiving antenna 12 Switching circuit (antenna selection means)
16 Vehicle speed detector (moving speed detector)
18 Microcomputer (control means, switching interval setting means)

Claims (2)

The antenna selection means for selecting an arbitrary reception antenna from among the plurality of reception antennas, and the antenna selection for switching and selecting a reception antenna for receiving a reception signal with good reception sensitivity among the plurality of reception antennas. A vehicle-mounted digital television receiver having control means for controlling the means,
A moving speed detecting means for detecting the moving speed of the vehicle;
When the moving speed detected by the moving speed detecting means increases, the antenna selecting means has a switching interval setting means for setting a long switching interval for switching and selecting the receiving antenna according to the moving speed. An in-vehicle digital television receiver characterized by the above. The antenna selection means for selecting an arbitrary reception antenna from among the plurality of reception antennas, and the antenna selection for switching and selecting a reception antenna for receiving a reception signal with good reception sensitivity among the plurality of reception antennas. A vehicle-mounted digital television receiver having control means for controlling the means,
A moving speed detecting means for detecting the moving speed of the vehicle;
When the moving speed detected by the moving speed detecting means is less than a predetermined speed, a switching interval for switching the receiving antenna by the antenna selecting means is set to a predetermined interval, and the moving speed is equal to or higher than the predetermined speed. In this case, the in-vehicle digital television receiving apparatus includes switching interval setting means for setting the switching interval to be longer than the predetermined interval.

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