JP3085087B2 - AV signal receiving method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for receiving an AV signal on a receiver side in an AV signal distribution system such as a CATV.

[0002]

2. Description of the Related Art Conventionally, the same program is time-shifted at a fixed interval, and is independently and repeatedly used by a plurality of channels.
V system (hereinafter, referred to as a near video on demand system). The receiver side of these systems selects and reproduces a desired channel from a plurality of channels, as in the case of ordinary broadcast wave reception.

However, in the above system, it is not possible to immediately start watching a desired program from the beginning. This is because the program is broadcast at time shift intervals, and the maximum waiting time necessary to watch from the beginning of the program is the time shift time.

[0004] Therefore, a system having a recording device capable of recording an AV signal for a time shift time on the receiver side can be devised as a means for viewing a desired program from the beginning at any time (Japanese Patent Laid-Open No. Hei 10 (1994)). 5-91510
No.). By always detecting the start of a program and playing back the AV signal recorded in the recording means while reproducing it, a system is used as a shift register that keeps recording the next minute so that the program to be watched can always be read at the beginning. I was able to start watching.

[0005]

However, in the system described above, in order to reproduce while recording, the AV signal recorded in the recording means is reproduced when the recorded content becomes useless and becomes unnecessary. This is a method for recording a simple AV signal. Therefore, when a pause occurs, the content is not reproduced and the recorded content is not useless, so that a recording location cannot be secured and a new AV signal cannot be recorded. Therefore, when the reproduction is started again after the pause, there is a problem that the reproduction of the AV signal during the pause period is impossible because the recording of the AV signal during the pause period is not performed.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an AV signal receiving method for detecting the occurrence of a temporary stop, selecting a reception channel in accordance with the occurrence time, and recording.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. An AV signal includes a time information component from the start of a program, and the receiver records an AV signal for a time shift time. Recording means having a capacity capable of
Upon receiving a command to pause the playback, the pause time is detected, and a specific channel having a time information component capable of reaching the pause time fastest is selected from the AV signals of the plurality of channels, and the selected channel matches the pause time. This is an AV signal receiving method in which the recordable remaining amount is sequentially recorded in the recording means from the time when the recording is performed.

[0008]

According to the present invention, a pause time is detected, and a specific channel having a time information component capable of reaching the pause time fastest is selected from AV signals of a plurality of channels. By sequentially recording the remaining recordable amount from the coincident point, even if the pause is performed at an arbitrary point, the desired program can be reproduced without interruption.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an AV system according to a first embodiment of the present invention.
FIG. 2 shows a block diagram of a signal receiver. In FIG. 1, reference numeral 12 denotes detection means for selecting and outputting a signal of a desired channel from a distributed AV signal, reference numerals 1 and 2 denote received AV signals output from the detection means 12, and reference numeral 13 denotes recording for recording a received AV signal 2. Means 3, a recording AV which is an output of the recording means 13;
Signal, 15 is a reproduction control means for controlling reproduction of the received AV signal 1 or the recorded AV signal 3, 16 is an operation input means for receiving an input from a user, 4 is an operation signal input from the operation input means 16, and 14 is a recording signal. The remaining amount calculating means for calculating the recordable remaining amount of the means 13, 5 is a remaining amount signal output from the remaining amount calculating means 14, 6 is the reproduction controlling means 15 and the detecting means 1.
A detection information signal 2 is output to the recording control signal 15 from the reproduction control means 15 to the recording means 13.

The operation of the AV signal receiving method according to the present embodiment configured as described above will be described below. There are a case where the received AV signal is an analog reception signal and a case where the AV signal is a digital reception signal. Here, the case of a digital reception signal will be described. In the case of the analog reception signal, only the differences will be described after the description of the digital reception signal.

The detecting means 12 selects an AV signal of a channel selected by the user from a plurality of received channels,
The receiving AV signal 1 is output. The delivered AV signal includes
The time information component from the start of the program is included. The reproduction control means 15 receives the received AV signal 1, separates a video signal or an audio signal from a time information component, and reproduces a video or an audio.
A specific example of the method of synchronously reproducing video and audio will be described later.

Normally, a program to be watched is selected and A
When the V signal is reproduced as it is, the received AV signal 2 need not be recorded in the recording means 13. The received AV signal 1 is simply reproduced as it is. However, it is assumed that the user temporarily wants to temporarily stop the reproduction and stop the reproduction for reasons such as wanting to leave the seat. When the operation input unit 16 receives a command requesting a pause, the operation signal 4 including the pause information is output.
It is output to the reproduction control means 15. Upon receiving the operation signal 4, the reproduction control means 15 refers to the currently reproduced time information component, and detects the pause time, which is the time at which the pause occurred. Next, a remaining amount signal 5 indicating the recordable remaining amount of the recording unit 13 is received from the remaining amount calculation unit 14. If there is a recordable remaining amount, the reproduction control means 15
The control for recording the V signal 2 is performed, but if not, the control for recording is not performed. The case where there is a recordable remaining amount will be described below.

The reproduction control means 15 outputs the detection information signal 6 to the detection means 12. The detection information signal 6 includes program ID information indicating the contents of the program, and information on the pause time at which the temporary reproduction of the program occurred. The program ID information is
This is information indicating which program is indicated when a plurality of programs are distributed at a time shift time interval on a plurality of channels. Further, the pause time is information indicating the time during which reproduction was performed from the beginning of the program until the pause occurred.

Upon receiving the detection information signal 6, the detecting means 12 narrows down the channels for distributing the corresponding program from the AV signals of a plurality of channels by using the program ID information.
Time information components are detected from the narrowed-down AV signals of a plurality of channels. Then, when a channel having a time information component that can reach the pause time fastest is selected, and a point that matches the pause time is found, the reproduction control means 1
5, the reproduction control means 15 outputs the recording control signal 7 to the recording means 13 and starts recording the received AV signal 2.
The recording capacity is the remaining recordable amount, and the remaining amount information is
It is included in the recording control signal 7 and transmitted to the recording means 13.

When the first pause occurs, the channel that receives the AV signal containing the time information component closest to the pause time is the channel that was received before the stop. Therefore, when the first pause occurs (when nothing is recorded in the recording means 13), the detecting means 12
Simplifies the procedure for detecting a desired channel and performs the same procedure for receiving a channel as before. The recording means 13 records the received AV signal 2 for a recordable remaining amount.

Next, a description will be given of the processing contents when a reproduction command is input again from the operation input means 16 after the suspension. The operation signal 4 indicating the reproduction information is transmitted to the reproduction control unit 1.
5 is input. Upon receiving the reproduction command, the reproduction control unit 15 receives the recorded AV signal 3 recorded in the recording unit 13 and performs reproduction. Upon reproduction, the recording means 13 detects the recording end time, which is the time information component of the last recorded AV signal, and outputs a recording control signal 7 to the reproduction control means 15. Then, the detection information signal 6 including the recording end time information and the program ID information is output to the detection means 12.

The detecting means 12 selects a specific channel having a time information component capable of reaching the recording end time fastest from the AV signals of a plurality of channels. When the time information component of the AV signal of the selected channel is detected and the time coincides with the recording end time, the detection information signal 6 is output to the reproduction control means 15 and the received AV signal is output to the recording means 13. The recording control signal 7 is output so as to record sequentially.

With the above configuration, the operation input means 1
By performing the operation of No. 6, control such as pause and reproduction can be performed, and it can be seen that even if the pause is performed at an arbitrary point, video and audio can be reproduced without interruption.

The recording means 13 records sequentially from the head position. When the recording reaches the final position, the recording is performed again by returning to the beginning. However, control is performed so as not to erase the recording of the AV signal that has been recorded and has not been read for reproduction. Therefore, the remaining capacity of the recording means 13 is a capacity obtained by subtracting a recording capacity that records an AV signal and has not been reproduced yet from an initially unused capacity. The recording means 13 needs at least a capacity capable of recording an AV signal having a length corresponding to the time of the time shift. This is because if the time of the time shift is waited, the same content program is distributed. Therefore, the recording means 13 records the AV signal only for the time shift,
It is used like an IFO (first in first out) type shift register.

It has been described that the capacity of the recording means 13 is a capacity capable of recording the AV signal for the time of the minimum time shift. On the other hand, receiving a pause command,
From the signal, a specific channel having a time information component that can reach the pause time is selected, and the time to start recording from a point in time that coincides with the pause time can be within the time shift time. This is because AV signals having the same contents are distributed at time shift time intervals. Therefore, it is sufficient to configure a recording unit having a recording capacity for the time shift time within the time shift time. Of course, it is needless to say that the recording medium may have a capacity capable of recording for the time shift time or more. Further, upon receiving a command for reproduction after the pause, a specific channel having a time information component that can reach the recording end time is selected from the AV signals of the plurality of channels, and recording is started from a point in time that coincides with the recording end time. The time is also within the time shift time. This too
This is the same reason as in the case of the suspension time.

As the recording means 13, for example, an optical disk player which is rewritable and in which a writing head and a reading head operate independently can be used. The reason why a head capable of independently performing writing and reading is required is that recording and reproduction must be performed simultaneously.

When the recording means 13 is rewritable and the write head and the read head are the same head, and the receiving speed of an external AV signal is lower than the read / write speed of the head, A hard disk drive capable of reading an AV signal for reproduction and writing the received signal for recording within the reception time of the above can also be used.

The above is a description of AV distributed from a plurality of channels.
The signal has been described as including the video signal, the audio signal, and the time information component. This AV signal may be composed of only the video signal and the time information component. This can be applied to a presentation system that provides only video without audio. Further, the present invention can be used for a system for distributing a still image without sound.

Further, the present invention can be applied to a multi-channel audio distribution service composed of only audio signals including voice and sound and time information components. In the case of this audio, it may be inconvenient to play back from the paused point. For example, it is assumed that there is a request that the user sits down in the middle of a song, but wants to listen again from the beginning of the song, not from the middle of the paused song. In order to solve this, an extra recording capacity is provided in the recording means 13 in addition to the time shift time, and the recording is always performed by reproducing the recorded AV signal recorded in the recording means 13. At the point where the stop occurred, the pause time was detected, the matching channel was detected and recording was started, and the recording capacity corresponding to several minutes to several tens minutes was subtracted from the remaining recordable amount for recording. At the time of playback, the playback may be performed retroactively from the pause time.
Needless to say, a similar configuration can be adopted when a video is included. In the case of a music information service, it is desirable to be able to provide an audio service with video from the beginning of the music when the music is resumed after a pause has occurred.

It is desirable that the reproduced video signal and audio signal are reproduced in synchronization. One example is a method of including a synchronization time information component in a video signal and an audio signal.
By including information relating to the time lapse information from the beginning of the program as a time information component and including it in each video and audio signal,
If reproduction is performed with reference to the time information, synchronization can be realized. Needless to say, the AV signal to be distributed needs to be edited in advance to include a time information component in order to achieve synchronization. At this time, if the AV signal is a digital signal, editing is easy. Since the video signal, the audio signal, and the time signal, which is a time information component, can all be represented by digital signals, signal synthesis, separation, and replacement can be easily performed.

Further, the video signal and the audio signal may be digitally compressed. If the signal is a compressed signal, the transmission capacity to be distributed and the recording capacity of the recording unit 13 can be reduced as compared to before the signal is compressed. When the transmission capacity decreases, a large number of programs can be provided by increasing the number of channels that can be distributed using the same transmission path. Also, if the recording capacity can be reduced, the receiver can be made smaller. This compressed digital data needs to include a time information component. By including the time information, the timing for decoding the compressed video and audio can be measured, and the time information necessary for synchronous reproduction of the video and audio can be obtained. It is preferable that the time information for this synchronization be used as it is as the pause time or the recording end time. MPEG (Mo) is used as a method for highly efficient encoding and data compression.
wing Pictures Expert Grou
p) The method is internationally standardized. In the MPEG, a method of providing a time signal for decoding and synchronization as well as video compression and audio compression is defined.

The case where the received AV signal is an analog received signal will be described. An analog reception signal is input to the detection unit 12. The detecting means 12 converts the data into digital coded data by coding means such as pulse code modulation. By encoding an analog signal into a digital signal, it is output as a received AV signal 1 and a received AV signal 2 as a digital signal in the same manner as in the case of the above-mentioned digital received signal, and is processed in the same manner.
The recording means 1 is encoded by encoding the digital signal.
3 can be digitally recorded. At the time of encoding, it is also possible to adopt a configuration in which compression encoding is performed, recorded, and decoded by the reproduction control means 15. By performing compression encoding, it is possible to reduce the recording capacity.
This analog reception signal must also include a time information component. This is because if time information is not included, it is impossible to detect a match based on time information.

Further, the following effects can be obtained by using the structure of this embodiment. Even if the broadcasting station distributes the AV signal by the near video on demand system, the receiver side
Control that allows temporary stop control at any point is possible. This is the same even if the number of receivers increases. A system is assumed in which a recording device corresponding to a receiver is provided on the broadcast station side, and a one-to-one distribution control that enables selection, reproduction, and suspension of a distribution program from the receiver side is assumed. I do. In such a one-to-one corresponding system, if the number of receivers increases, the distribution request from all receivers can be satisfied unless the number of recording devices is increased in response to the increase in the number. Can not. However, even if the number of recording devices is increased, it is impossible to respond to a distribution request exceeding the limit due to the limitation of the capacity of the transmission path for transmitting the AV signal. However, in the present embodiment, the broadcasting station only has to distribute a plurality of programs independently of a plurality of channels at time shift intervals. AV more than minimum (capacity for time shift interval) on receiver side
Since the signal is recorded, it is possible to respond to a request such as a temporary stop.

According to the present embodiment, when a pause is generated from the AV signals of a plurality of channels or when the reproduction is resumed after the pause, the AV signal is recorded from the time when the time information coincides with the time information. Is performed at an arbitrary point, a receiver that reproduces a desired program without interruption can be configured.

Next, a second embodiment will be described. FIG. 2 is a block diagram showing an AV signal receiver according to a second embodiment of the present invention. In the second embodiment, in addition to the configuration of the first embodiment, reservation information for distribution is recorded, and reservation recording control is executed. In FIG. 2, reference numeral 17 denotes a reservation execution unit for executing reservation control, and 8 denotes a reservation signal output from the reservation execution unit 17 to the detection unit 12. Others are the same as FIG.

The operation of this embodiment is as follows. When the user has previously reserved a program (using the operation input unit 16 or the like), the reservation executing unit 17 outputs the reservation signal 8 to the detecting unit 12. The reservation signal 8 includes:
Includes program ID information indicating the contents of the desired program. The detecting means 12 selects a channel on which the reserved program is distributed, and detects the head of the reserved program. When the head is detected, the detection information signal 6 informs the reproduction control means 15 of the detection, issues a recording control signal 7, and records the received AV signal 2 in the recording means 13 by the recording capacity. Then, upon receiving a reproduction command from the user, the reproduction control means 15 starts reproducing the AV signal recorded in the recording means 13.
The recording control signal 7 including the recording end time information of the last AV signal recorded on the recording means 13 is transmitted to the reproduction control means 1.
5 and outputs it to the detection means 12 as a detection information signal 6 to which the program ID information is added. As in the first embodiment, the detecting means 12 selects a specific channel having a time information component that can reach the recording end time fastest from a plurality of channels of AV signals, detects the time information component, The time point coincident with the recording end time is detected, and if found, the detection information signal 6 is transmitted to the reproduction control means 15 to start recording, the recording control signal 7 is generated, and the recording means 13 starts recording. . Since all the components described in the first embodiment are included, even if the playback is started and then the pause is performed,
A more than the time shift time from the time when the time information matches
The V signal is recorded.

Therefore, when a program is reserved in advance,
It is possible to configure a receiver that can start a desired video at a desired time and that can provide a video service without interruption of a reproduced video even if a pause or the like is performed halfway on the user's convenience.

Next, a third embodiment will be described. The third embodiment will be described with reference to the block diagram of the AV signal receiver in FIG. The configuration of the third embodiment is the same as that of the first embodiment, but the function of each component is increased as compared with the first embodiment.

In FIG. 1, reference numeral 12 denotes detection means for selecting and outputting signals of a plurality of desired channels from the distributed AV signals, and reference numerals 1 and 2 denote a plurality of reception signals which are outputs of the detection means 12.
V signal, 13 is recording means for recording a plurality of received AV signals 2, 3 is a plurality of recorded AV signals output from the recording means 13, 15 is a plurality of received AV signals 1 or recorded AV signals 3
Control means for controlling the reproduction of data, 16 is an operation input means for receiving an input from a user, 4 is an operation signal input from the operation input means 16, and 14 is a remaining amount calculation for calculating a recordable remaining amount of the recording means 13. The means 5 is a remaining amount signal output from the remaining amount calculating means 14, the detection information signal 6 is output from the reproduction control means 15 to the detecting means 12, and the reproduction control means 1 is
5 is a recording control signal output to the recording means 13.

A of the third embodiment configured as described above
The operation of the V signal receiving method will be described below.
The detecting means 12 selects AV signals of a plurality of channels selected by the user from the plurality of received channels, and outputs a plurality of received AV signals 1. The delivered AV signal includes
The time information component from the start of the program is included. Reproduction control means 15
Receives a plurality of received AV signals 1 and first decomposes them into received AV signals for each channel. Next, the received AV signal for one channel is divided into a video signal and an audio signal and a time information component, and the video and the audio are reproduced.

Alternatively, the detection means 12 is configured to generate separate received AV signals from the selected AV signals of the plurality of channels, and to input the received AV signals to the reproduction control means 15. Is also good.

Each means operates assuming that there are AV signals to be reproduced or recorded for a plurality of programs. Pause detection operation,
The playback detection operation after the pause is the same as in the first embodiment. Pause is controlled independently for each program being played. This is because when a plurality of videos are being reproduced on one screen, pause and reproduction of the reproduced video can be controlled independently.

The recording means 13 stores a plurality of received AV signals 2
Requires the capacity to be able to record Receive at the same time,
By determining the number of channels that can be displayed, the capacity obtained by multiplying the number of simultaneously receivable channels by the time shift time is the minimum required recording capacity of the recording unit 13. The recording means 13 divides and records the received AV signal of each channel. Then, the remaining amount calculating unit 14 checks the divided and recorded capacity, and calculates a recordable remaining amount. Although the pause has been described, the reproduction after the pause is the same as in the first embodiment. Only a point corresponding to a plurality of recording AV signals 3 is different.

According to the third embodiment, a plurality of channels A
A plurality of AV signals selected by the user are selected from the V signal, and when the pause of reproduction of each of the selected programs occurs, or when the reproduction is resumed after the pause, the AV signals are separately separated from the time when the time information matches the time information. By recording the AV signal, it is possible to configure a receiver that reproduces a desired program without interruption even if the pause is performed at an arbitrary point.

Further, the configuration of the third embodiment has a second
The reservation executing means 17 described in the embodiment can be combined. When a plurality of programs have been reserved in advance, the heads of the plurality of reserved programs are detected and recorded in the recording means 13 for the recordable capacity within the time shift time. While reproducing one or more recorded AV signals 3 recorded in the recording means 13, each recording end time recorded in the recording means 13 is detected, and A
A specific channel having a time information component capable of reaching the recording end time fastest is selected from the V signal, and recording is performed from a time point coincident with the recording end time. With this configuration, if a reservation is made in advance, a plurality of programs can be reproduced at any time, and pause control can be separately performed for each program.

[0042]

As described above, according to the present invention, in a system in which a plurality of identical programs are time-shifted for a predetermined time and distributed independently and repeatedly, a received AV signal includes a time component from the start of the program. On the receiver side, the pause time is detected, a specific channel having a time information component that can reach the pause time fastest is selected from the AV signals of the plurality of channels, and recording is performed from the time when the pause time coincides with the specific channel. By sequentially recording the possible remaining amount, it is possible to configure a receiver that reproduces a desired program without interruption even if the pause is performed at an arbitrary point.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an AV signal receiver according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an AV signal receiver according to a second embodiment of the present invention.

[Explanation of symbols]

 12 detecting means 13 recording means 14 remaining amount calculating means 15 reproduction controlling means 16 operation input means 17 reservation executing means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-303249 (JP, A) JP-A-6-98323 (JP, A) JP-A-6-113301 (JP, A) JP-A-60-1985 94587 (JP, A) JP-A-5-91510 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 7/10 H04N ^7/ 14-7/173 H04N ^7/ 20- 7/22

Claims (11)

(57) [Claims] 1. A receiver for receiving a plurality of AV signals of a plurality of channels which are time-shifted by a predetermined time for a plurality of identical programs and which are independently and repeatedly transmitted, wherein the AV signals include a time from the beginning of the program. Recording means having an information component and having a capacity capable of recording the AV signal having a length equal to or longer than the time of the time shift, and when receiving a command to pause the reproduction, the time information at the time of occurrence of the pause A pause time representing a component is detected, a remaining recordable amount of the recording means is obtained, and a specific channel having a time information component capable of reaching the pause time fastest is selected from the AV signals of the plurality of channels. When the reproduction command is received after the pause, the AV signal recorded in the recording means is reproduced. While detecting the recording end time indicating the time information component of the last AV signal recorded in the recording means, the recording means has a time information component capable of reaching the recording end time most quickly from the AV signals of the plurality of channels. A method for receiving an AV signal, wherein a specific channel is selected, and recording is sequentially performed from a time point coincident with the recording end time. 2. The AV signal according to claim 1, wherein the AV signal is transmitted as digital data, the recording means is constituted by a digital recording device, and the digital data is recorded in the recording device as it is. Receiving method. 3. A specific channel having a time information component that can reach the pause time within a time shift time is selected from AV signals of a plurality of channels after receiving the pause command, 2. The recording for the recordable remaining amount is performed from the time when the recording time matches.
The AV signal receiving method according to the above. 4. After receiving a command for reproduction after a pause,
The method according to claim 1, wherein a specific channel having a time information component that can reach a recording end time within a time shift time is selected from the AV signals of a plurality of channels, and recording is performed from a point in time that coincides with the recording end time. 2. The method for receiving an AV signal according to item 1. 5. When a reservation has been made in advance, the head of the reserved program is detected, a recordable capacity is recorded in the recording means, and when a reproduction command is received, the program is recorded in the recording means. While reproducing from the beginning of the AV signal, the recording end time is detected, and a specific channel having a time information component that can reach the recording end time fastest is selected from the AV signals of the plurality of channels. 2. The recording method according to claim 1, wherein the recording is performed sequentially from a time point at which the number matches.
V signal receiving method. 6. When an instruction to temporarily suspend reproduction of one or more specific AV signals being received is received when an AV signal of a plurality of specific channels is selected from AV signals of a plurality of channels, Detecting each pause time, obtaining a recordable remaining amount of the recording means, and selecting a specific channel having a time information component capable of reaching the pause time fastest from the AV signals of the plurality of channels,
2. The AV signal receiving method according to claim 1, wherein the recordable remaining amount is recorded from a time point coincident with the pause time. 7. The AV signal receiving method according to claim 2, wherein the AV signal is compressed digital data. 8. The AV signal receiving method according to claim 2, wherein the AV signal is a compressed digital AV data of a video signal and an audio signal time-synchronized with the video signal. 9. The digital audio system according to claim 2, wherein the transmitted AV signal is digital audio data composed of an audio signal such as a voice signal and an audio signal.
V signal receiving method. 10. A video signal of a plurality of specific channels is selected from AV signals of a plurality of channels, and one or more specific videos being received are temporarily stopped.
When a reproduction command is received again, one or more AV signals recorded in the recording means are reproduced, and each recording end time recorded in the recording means is detected. 7. The AV signal receiving method according to claim 6, wherein a specific channel having a time information component capable of quickly reaching the recording end time is selected, and recording is sequentially performed from a time point coincident with the recording end time. 11. When a plurality of programs have been reserved in advance, the heads of the plurality of reserved programs are detected, recorded in the recording means for a recordable capacity within a time shift time, and a reproduction command is received. And detecting one or more recording end times recorded in the recording means while reproducing one or more AV signals recorded in the recording means.
11. The AV according to claim 10, wherein a specific channel having a time information component capable of reaching the recording end time fastest is selected from the V signal, and recording is sequentially performed from a time coincident with the recording end time. Signal receiving method.