JP2005191615A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver capable of receiving a broadcast signal adopting a different broadcast system and quickly displaying a video image of a channel after switching. <P>SOLUTION: When a viewer instructs channel switching, a microcomputer 3 instructs a channel selection circuit 5 receptible of a broadcast channel adopting a different broadcast system to switch a reception channel, increases the AGC sensitivity of an AGC circuit 10, reads a vertical frequency with respect to the switching reception channel from a memory 4, and switches the vertical frequency of a vertical drive circuit 7 to the read vertical frequency. The microcomputer 3 decreases the AGC sensitivity of the AGC circuit 10 after a lapse of a prescribed time set depending on the presence of a difference between the vertical frequency of the channel having been received before switching of the reception channel and the vertical frequency of the reception channel after the switching. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a receiving apparatus capable of receiving signals of different broadcasting systems.

  In the Asian region, there are regions where both PAL system (vertical frequency 50 Hz) television broadcast and NTSC system (vertical frequency 60 Hz) television broadcast signals can be received. Are designed to receive both types of signals. In this case, each time the channel is switched, the receiver performs a process for determining the vertical frequency of the received signal, and processes the received video signal according to the determination result.

  The vertical frequency determination process takes time, and therefore it takes time to display the image of the channel switched to the receiver. Therefore, when presetting a reception channel in a television receiver, a proposal has been made to enable quick switching by storing the above broadcasting system together. For example, in Patent Document 1, method discrimination data is stored in a memory together with reception channel data when a reception channel is preset, and method discrimination data is obtained instantaneously at the time of channel switching so as to suppress the occurrence of audio buzz noise at the time of channel switching. A receiving apparatus is disclosed.

However, in the present busy situation, there is a demand for channel image display by faster switching.
JP-A-6-225239 (2nd page, FIG. 1)

  As described above, conventionally, there has been a proposal for switching the method instantaneously by storing the method identification data together with the reception channel data in the memory at the time of presetting the reception channel and obtaining the method identification data instantaneously at the time of channel switching. The company is seeking to further shorten the switching time.

  The present invention has been made in view of these points, and an object of the present invention is to provide a receiving apparatus capable of displaying video of a channel after switching more quickly.

  In order to achieve the above object, a receiving apparatus according to claim 1 includes a channel selection circuit capable of receiving broadcast channels having different broadcasting systems, a memory storing a vertical frequency applied to a reception channel together with data related to the reception channel, and A vertical deflection circuit for supplying a signal for vertical deflection, an AGC circuit for controlling the gain of the vertical deflection circuit, instructing the channel selection circuit to switch the reception channel, and increasing the AGC sensitivity of the AGC circuit, Control means for reading the vertical frequency applied to the switching reception channel from the memory and switching the vertical frequency of the vertical deflection circuit to the read vertical frequency, the control means receiving before switching the reception channel Depending on the difference between the vertical frequency of the channel and the vertical frequency of the receiving channel after switching It is characterized in that is configured to after a constant and predetermined time lowers the AGC sensitivity of the AGC circuit.

The receiving apparatus according to claim 2 is the receiving apparatus according to claim 1, wherein the vertical frequency of the channel received before switching the receiving channel is the same as the vertical frequency of the receiving channel after switching for the predetermined time. The case is set to be short, and the case where the difference is set is set to be long.

  Further, a receiving device according to claim 3 is a channel selection circuit capable of receiving broadcast channels of different broadcasting systems, a memory storing data related to the reception channel and a vertical frequency in image display related to the reception channel, and vertical deflection. A vertical deflection circuit for supplying signals for use, an AGC circuit for controlling the gain of the vertical deflection circuit, an instruction to switch the reception channel to the channel selection circuit, and an increase in AGC sensitivity of the AGC circuit. Control means for reading the vertical frequency in the image display relating to the switching reception channel, and switching the vertical frequency of the vertical deflection circuit to the read vertical frequency, the control means receiving before switching the reception channel In the image display on the channel and the receiving channel after switching It is characterized in that is configured to lower the AGC sensitivity of the AGC circuit after a predetermined time set in accordance with the difference of the vertical frequency.

  According to a fourth aspect of the present invention, there is provided the receiving device according to the third aspect, wherein the predetermined time is the vertical frequency in the image display of the channel received before the switching of the receiving channel and the vertical in the image display of the receiving channel after the switching. When the frequency is close, it is short, and when it is greatly different, it is set long.

  ADVANTAGE OF THE INVENTION According to this invention, the receiver which can display the channel image after switching more quickly can be provided.

  Hereinafter, embodiments of a receiving apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a circuit diagram showing an embodiment of a receiving apparatus according to the present invention. In the figure, reference numeral 1 denotes a remote control transmitter for instructing the receiving apparatus to select a channel to be viewed and adjusting the volume. Reference numeral 2 denotes a remote control receiver that receives an infrared instruction signal from the remote control transmitter 1, and is connected to a microcomputer 3 for performing various controls of the receiving apparatus. The microcomputer 3 is connected to a memory 4 that stores channel data (broadcast frequency and channel number, etc.) and a broadcasting system (PAL system or NTSC system) at the time of channel presetting by the viewer. The video signal processing circuit 6 is connected to the vertical output circuit 8 via the vertical drive circuit 7. These vertical drive circuit 7 and vertical output circuit 8 generate a signal for vertical deflection of a monitor (not shown) of the receiving apparatus.

  The channel selection circuit 5 is connected to a system discrimination circuit 9 that discriminates the broadcast system of the received channel from the frequency (vertical frequency) of the vertical synchronization signal of the received signal. The output terminal of the circuit 9 is connected to the microcomputer 3. It is connected to the. Further, a vertical AGC circuit 10 is connected to the microcomputer 3, and an output terminal of the vertical AGC circuit 10 is connected to a vertical drive circuit 7.

  Next, before explaining the operation at the time of channel switching of the apparatus of FIG. 1, the channel preset operation by the viewer will be explained. Before the first viewing, the viewer performs a channel preset. This is to store the channel (frequency) desired to be received together with the desired channel number in the memory 4, and based on an instruction displayed on a monitor screen (not shown) of the apparatus using the remote control transmitter 1, for example. Is set. At this time, the microcomputer 3 also stores the vertical frequency detected by the method discrimination circuit 9 from the vertical synchronization signal of the reception channel in the memory 4 together with the channel frequency and the set channel number.

  Next, the operation at the time of channel switching of the apparatus of FIG. 1 will be described with reference to FIG. FIG. 2 is a flowchart relating to the operation of the microcomputer 3 at the time of channel switching. First, it is confirmed whether or not there is a CH switching instruction from the remote control transmitter 1 (or an operation button (not shown) provided on the apparatus main body) (step S1). If there is no CH switching instruction (NO in step S1), the process returns to step S1 again. If there is a CH switching instruction (YES in step S1), the channel selection circuit 5 is instructed to switch the channel to be received (step S2).

  Thereafter, the microcomputer 3 reads out the vertical frequency applied to the above-mentioned channel selection channel to be switched from the memory 4 (step S3) and increases the AGC sensitivity of the vertical AGC circuit 10 (step S4). Further, the vertical frequency of the vertical drive circuit 7 is switched to the vertical frequency read in step S3. Next, it is checked whether or not the read vertical frequency (that is, the vertical frequency after channel switching) is the same as the vertical frequency of the channel that was previously received (that is, before channel switching) (step S6). If they are the same (that is, the channel before switching and the channel after switching are broadcasts of the same broadcasting system) (YES in step S6), the time T for increasing the AGC sensitivity of the vertical AGC circuit 10 is set short (step S7). ). If they are not the same (that is, the channel before switching and the channel after switching are broadcasts of different broadcasting systems) (NO in step S6), the time T for increasing the AGC sensitivity of the vertical AGC circuit 10 is set longer (step S8). ).

  Then, it is determined whether or not the time T for increasing the AGC sensitivity set in step S7 or S8 has elapsed (step S9). If it has not elapsed (NO in step S9), the process returns to step S9 again. If so (YES in step S9), the AGC sensitivity of the vertical AGC circuit 10 is lowered (step S10).

  According to the embodiment described above, the time T for increasing the AGC sensitivity of the vertical AGC circuit 10 is different depending on whether the vertical frequency of the channel after switching matches that of the channel before switching. When the vertical frequency of the channel after switching coincides with the channel before switching, the time required for the vertical frequency to be switched and the vertical amplitude to be stabilized is shorter than the case where the time T for increasing the AGC sensitivity is not different. I can do it. Therefore, the muting time of the video signal that is performed until the vertical amplitude is stabilized can be shortened as a whole, and the time until the image output after the channel switching operation can be shortened as compared with the prior art.

  Next, another embodiment of the present invention will be described. Some receiving apparatuses convert the vertical frequency of the received signal to twice to improve the image quality of the display image. For example, the vertical frequency of a PAL signal with a vertical frequency of 50 Hz is converted to a double speed display by converting it to 100 Hz, or the vertical frequency of an NTSC signal with a vertical frequency of 60 Hz is converted to a double speed of 120 Hz to display a double speed. It is to do.

  When the setting for the conversion is left to the viewer's selection, the PAL signal is displayed as it is without converting the vertical frequency, but the NTSC signal is converted to 120 Hz which is twice the vertical frequency. Display, and the PAL system signal and the NTSC system signal can be displayed by converting the vertical frequency to 100 Hz and 120 Hz, respectively, or the PAL system signal and the NTSC system. Any of these signals may be displayed as it is without converting the vertical frequency.

In such a case, depending on the viewer's selection, the vertical frequency of the display image may be largely switched by channel switching (for example, the vertical frequency is switched from 120 Hz to 50 Hz), or may not change much (for example, When the vertical frequency of the display image is switched from 100 Hz to 120 Hz, or when the vertical frequency is also switched from 50 Hz to 60 Hz).

  Therefore, if the vertical frequency does not become the same due to channel switching, the time T for increasing the AGC sensitivity of the vertical AGC circuit 10 is not always set longer, and the display video is also considered in consideration of the selection for the viewer's double speed display. It can be considered that the time T for increasing the AGC sensitivity of the vertical AGC circuit 10 is set to be long only when the vertical frequency of the vertical AGC circuit is largely switched. That is, even when the vertical frequency of the display video is switched and not the same by channel switching, the time T for raising the AGC sensitivity is set to be short by setting the time T for raising the AGC sensitivity to a short time when there is not much change. In this case (in this case, since the time T needs to be set as the convergence time of the vertical amplitude when the vertical frequency change is the largest, it takes time to display an image on the display screen even when the frequency change is small). Thus, the time required until the vertical amplitude of the display image is switched and the vertical amplitude is stabilized can be shortened.

  3 and 4 are a block diagram and a flowchart for explaining the embodiment as described above. In FIG. 3, the same or equivalent parts as in FIG.

  3 are greatly different from FIG. 1 in a microcomputer 13 and a memory 14, a video signal processing circuit 16, a vertical drive circuit 17, and a vertical output circuit 18. For example, the microcomputer 13 also stores the viewer settings (double speed display or normal display) for the double speed display in the memory 14 for each reception method. The video signal processing circuit 16 has a circuit configuration corresponding to double-speed display, and the vertical drive circuit 17 and the vertical output circuit 18 similarly output a vertical frequency corresponding to double-speed display in addition to the normal display vertical frequency. It is configured to be able to.

  Next, the operation of the apparatus shown in FIG. 3 will be described. Before the first viewing, the viewer performs channel presetting, which is the same as in the previous embodiment. This embodiment is largely different from the previous embodiment in that the viewer additionally sets whether or not double-speed display is desired for each of the case where the NTSC format signal is received and the case where the PAL format signal is received. It is a difference. Note that when the device is shipped, for example, double-speed display is set as a standard setting, and only when the viewer desires normal display, for example, based on an instruction displayed on a monitor screen (not shown) of the device using the remote control transmitter 1, for example. Setting operation can be simplified.

  In the case of the present embodiment, the microcomputer 13 stores the setting for double speed display (whether double speed display or normal display) in the memory 14 for each reception method. For example, when an NTSC system signal is received, double speed display is performed, and when a PAL system signal is received, normal display is performed. Finally, in the memory 14, whether the channel frequency, the set channel number, the vertical frequency, and the NTSC system signal and the PAL system signal are each displayed at double speed or normal display. The viewer's settings are stored.

  Next, the operation at the time of channel switching of the apparatus of FIG. 3 will be described with reference to FIG. FIG. 4 is a flowchart relating to the operation of the microcomputer 13 at the time of channel switching. First, it is confirmed whether there has been a CH switching instruction from the remote control transmitter 1 (or an operation button (not shown) provided on the apparatus body) (step S11). If there is no CH switching instruction (NO in step S11), the process returns to step S11 again. If there is a CH switching instruction (YES in step S11), the channel selection circuit 5 is instructed to switch the channel to be received (step S12).

  Thereafter, the microcomputer 13 reads out the vertical frequency and display setting (double speed display or normal display) relating to the above-mentioned channel selection channel to be switched from the memory 14 (step S13) and increases the AGC sensitivity of the vertical AGC circuit 10 (step S13). S14). Further, the vertical frequency of the vertical drive circuit 17 is switched to the vertical frequency for display calculated based on the vertical frequency read in step S13 and the display setting (120 Hz if the vertical frequency of the reception channel is 60 Hz and the display setting is double speed display). (Step S15).

  Next, it is checked whether or not the display vertical frequency is the same as the display vertical frequency of the channel previously received (that is, before switching) (step S16). If they are the same (that is, the channel before switching and the channel after switching are broadcasts of the same broadcasting system) (YES in step S16), the time T for increasing the AGC sensitivity of the vertical AGC circuit 10 is set short (step S17). ). If they are not the same (that is, the channel before switching and the channel after switching are broadcasts of different broadcasting systems) (NO in step S16), the display vertical frequency is greatly different between the channel before switching and the channel after switching. It is determined whether or not to perform (step S18).

  If it is determined that there is no significant difference (when the vertical frequency is switched from 100 Hz to 120 Hz, or when the vertical frequency is also switched from 50 Hz to 60 Hz) (NO in step S18), the process moves to step S17, where there is a large difference. If it is determined (YES in step S18), the time T for increasing the AGC sensitivity of the vertical AGC circuit 10 is set longer (step S19).

  Then, it is determined whether or not the time T for increasing the AGC sensitivity set in step S17 or S19 has elapsed (step S20). If it has not elapsed (NO in step S20), the process returns to step S20 again. If so (YES in step S20), the AGC sensitivity of the vertical AGC circuit 10 is lowered (step S21).

  According to the embodiment described above, since the time for increasing the vertical AGC sensitivity can be set to an optimum time according to the switching frequency, it is possible to perform channel switching processing at a higher speed than in the past.

The circuit block diagram which shows one Embodiment of the receiver which becomes this invention. The flowchart for demonstrating operation | movement of the apparatus of FIG. The circuit block diagram which shows other embodiment of the receiver which becomes this invention. FIG. 4 is a flowchart for explaining the operation of the apparatus of FIG. 3. FIG.

Explanation of symbols

1: Remote control transmitter 2: Remote control receiver 3: Microcomputer 4: Memory 5: Tuning circuit 7: Vertical drive circuit 8: Vertical output circuit 9: Method discrimination circuit 10: Vertical AGC circuit

Claims (4)

  A channel selection circuit capable of receiving broadcast channels of different broadcasting systems, a memory storing the data related to the reception channel and the vertical frequency applied to the reception channel, a vertical deflection circuit supplying a signal for vertical deflection, and the vertical deflection An AGC circuit for controlling the gain of the circuit; and instructing the channel selection circuit to switch the reception channel, increasing the AGC sensitivity of the AGC circuit, and further reading out the vertical frequency applied to the switching reception channel from the memory. Control means for switching the vertical frequency of the received channel to the read vertical frequency, the control means depending on the difference between the vertical frequency of the channel received before switching the receiving channel and the vertical frequency of the receiving channel after switching. AGC sensitivity of the AGC circuit after elapse of a predetermined time set Receiving apparatus characterized by being configured to lower.   2. The receiving apparatus according to claim 1, wherein the predetermined time is set to be short when the vertical frequency of the channel received before switching the receiving channel is the same as the vertical frequency of the receiving channel after switching, and to be long when the channel is different. A receiving device characterized by that.   A channel selection circuit capable of receiving a broadcast channel having a different broadcasting system, a memory storing a vertical frequency in image display applied to the reception channel together with data applied to the reception channel, a vertical deflection circuit supplying a signal for vertical deflection, An AGC circuit for controlling the gain of the vertical deflection circuit, and a command for switching the reception channel to the channel selection circuit, increasing the AGC sensitivity of the AGC circuit, and further, a vertical frequency in image display from the memory to the switching reception channel Control means for switching the vertical frequency of the vertical deflection circuit to the read vertical frequency, and the control means displays the image on the channel received before switching the receiving channel and the receiving channel after switching. Set according to the vertical frequency difference in Receiving apparatus characterized by being configured to lower the AGC sensitivity of the AGC circuit after a certain time. 4. The receiving apparatus according to claim 3, wherein the predetermined time is short when the vertical frequency in the image display of the channel received before the switching of the receiving channel is close to the vertical frequency in the image display of the receiving channel after the switching, and is largely different. The receiving apparatus is characterized in that it is set for a long time.

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