JP2000236528A - Receiver and reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly apply reception processing to a plurality of kinds of digital broadcast signals whose transmission parameters differ from each other. SOLUTION: A reception parameter used to receive a channel whose transmission is confirmed is entered as a default value (step S1). A channel is selected with this reception parameter (step S2). An NIT is separated and extracted from a transport stream relating to the selected channel and the NIT is stored in a nonvolatile memory (step S3). When a change of channel is instructed, a reception parameter used to receive a new channel is confirmed by referencing the NIT stored in the nonvolatile memory (step S6). Whether or not the revision of the reception parameter is furthermore required is discriminated (step S7), and when the revision is required, the processing proceeds to the step S8 and the setting relating to control of a front end section 2 is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus and a receiving method suitable for use in digital cable broadcasting for retransmitting digital CS broadcast signals, for example.

[0002]

2. Description of the Related Art In current cable broadcasting, terrestrial broadcasting, BS (Broadcasting Satellite) broadcasting and CS
(Communication Satellite) The original material such as a broadcast is retransmitted. In analog cable broadcasting, retransmission of any original material is retransmitted in the same modulation scheme, so there is no need to consider the modulation scheme in the demodulation processing on the receiving device side.

[0003] In recent years, digital CS broadcast services have been started, and cable broadcasting has been digitized accordingly. In digital cable broadcasting for retransmitting digital CS broadcasting, 64QAM (Quadrature Amplitude Modulatio
n) The method is adopted. Therefore, digital CS
In a digital cable broadcast in which only a broadcast is retransmitted, the receiving device only needs to perform modulation corresponding to the 64QAM system, and there is no need to perform demodulation processing in consideration of the modulation system.

[0004]

With the increase in CS transmission output in digital CS broadcasting, it has been studied to increase the data transmission rate by reducing the Viterbi code rate. There is a possibility that it is necessary to adopt a modulation method other than 64QAM as a modulation method when performing transmission.

In the case of re-transmitting these broadcast signals in a digital cable broadcast in which a digital BS broadcast, a digital terrestrial broadcast, etc. have been started, the digital cable broadcast must be adapted to the modulation method of each broadcast signal. , A plurality of types of modulation schemes are used, and it becomes necessary for the receiving apparatus to perform demodulation processing in consideration of the plurality of types of modulation schemes.

Accordingly, an object of the present invention is to provide a receiving apparatus and a receiving method capable of accurately performing a receiving process such as demodulation on a plurality of types of digital broadcast signals having different transmission specifications such as a modulation method and a frequency. Is to provide.

[0007]

According to a first aspect of the present invention, there is provided a receiving apparatus for receiving a digital broadcast signal, a receiving means for receiving a supplied digital broadcast signal, and a receiving means for receiving the digital broadcast signal. Input means for inputting the reception parameter as the initial setting value, and obtains information on the reception parameter included in the digital broadcast signal received by the operation of the receiving means under the initial setting value,
A receiving apparatus characterized in that setting of a receiving parameter associated with a channel switching process is automatically performed in accordance with information on the obtained receiving parameter.

According to a sixth aspect of the present invention, there is provided a receiving apparatus for receiving a digital broadcast signal, a receiving means for receiving the supplied digital broadcast signal, and a receiving means for receiving the digital broadcast signal. A memory for storing the type of reception parameters, and reading out the reception parameters one by one from the memory, and when the digital broadcast signal is not properly received by the operation of the receiving means under the read reception parameters, When the digital broadcast signal is properly received, the reception parameter is read again to perform the operation of the receiving unit under the read reception parameter, and according to the information on the reception parameter included in the digital broadcast signal, Automatic setting of reception parameters for channel switching It is a receiving apparatus according to claim.

According to a seventh aspect of the present invention, in the receiving method for receiving a digital broadcast signal, a step of inputting a reception parameter usable for receiving the supplied digital broadcast signal as an initial set value is provided. Receiving a digital broadcast signal below, and acquiring information on a reception parameter included in the digital broadcast signal received by the reception step, and switching a channel according to the information on the acquired reception parameter. This is a receiving method characterized in that setting of receiving parameters accompanying processing is automatically performed.

The invention according to claim 8 is a receiving method for receiving a digital broadcast signal, wherein the reception parameters are sequentially stored from a memory storing a plurality of types of reception parameters assumed to be usable for receiving the digital broadcast signal. A reception parameter reading step of reading out one type of reception parameter, a reception trial step of performing a process for receiving a digital broadcast signal under the reception parameter read by the reading step, and a digital broadcast signal by the reception trial step. Determine whether or not to be received accurately, if not correctly received, has a step to shift to the reception parameter reading step again, if the digital broadcast signal is received properly by the reception trial step, Reception parameters included in digital broadcast signals According Such information is a reception method being characterized in that to automatically perform the setting of the reception parameters associated with the process of switching channels.

According to the invention as described above, a digital broadcast signal such as a digital cable broadcast signal is received by a user's input or the like or by selection from a plurality of reception parameters stored in a memory in advance by trial and error. A reception parameter that can be used to perform channel switching is set in accordance with information on a reception parameter such as NIT obtained from a digital broadcast signal received under the reception parameter set in this manner. Accompanying reception parameters are automatically set.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A digital CS broadcast service has already been started, and a digital cable broadcast for retransmitting a digital CS broadcast is being performed. Here, the transmission path of digital cable broadcasting and the configuration of the receiving apparatus will be briefly described. For example, on the receiving device side, a dedicated adapter called a set-top box is used. The set-top box includes, for example, a tuner circuit, a QAM receiving circuit, an error correcting circuit, an MPEG (Moving
Picture Experts Group) compatible decoder, NTSC
(National Television System Committee), which comprises an encoder, an audio decoder, a D / A converter, a host processor, a switch circuit, and the like, and is used by being mounted on a television receiver. Further, as a transmission path to the set box, for example, a conventional cable broadcasting network that distributes television broadcasting by a coaxial cable is used as it is.

A digital cable broadcasting station is provided with a video database in which digitized video information is stored, and the video information of the video database is supplied to one input terminal of a mixer via a 64-level QAM modulator. Supplied. An analog television broadcast signal is supplied from the existing analog cable broadcasting station to the other input terminal of the mixer. Digital QA at the mixer
The M-modulated output and the analog television broadcast signal are mixed, and the output of the mixer is supplied to the optical transmitter. The output of the mixer is modulated by a predetermined modulation method in the optical transmitter,
It is supplied to an optical receiver via an optical fiber. The received output is demodulated in the optical receiver, and the demodulated output is distributed to each contracted home via a plurality of amplifiers serving as repeaters and a coaxial cable connecting the amplifiers.

Each video device is connected to a coaxial cable drawn into the home. For example, as one connection form, a coaxial cable is connected to a VTR (Video Tape Recorder), and further, a television receiver is connected to the VTR. In another connection form, a coaxial cable is connected to a set-top box, and a television receiver is connected to the set-top box. In the case of the connection mode using this set-top box, it is possible to selectively watch conventional analog cable broadcasting and digital cable broadcasting.

In digital CS broadcasting, a QPSK (four-phase modulation) system is adopted as a digital modulation system. For example, one of the digital CS broadcasts "SkyP
In the case of "erfecTV!", the data is transmitted in a band of 27 MHz, the total data transmission rate including an error correction code called Viterbi code is specified as 42.192 Mbps, and the rate excluding Viterbi code is specified as 31.644 Mbps. I have. In the digital cable broadcasting for retransmitting such digital CS broadcasting, the transmission band is 6 MHz, and the C / N of the cable is considerably better than that of the CS broadcasting, so that the Viterbi code is not included. 64-value QAM is used as a modulation method.

QAM is a digital modulation method called quadrature amplitude modulation, in which each of two orthogonal carriers (I and Q) is digitally amplitude-modulated into multiple values, and I and Q are modulated.
And transmitting the result. Also, 64-value QAM
Indicates that I and Q are digitally amplitude-modulated into eight values,
This is so called because 64 data are developed on the Q plane. 31.644 using this 64-level QAM modulation method.
By modulating the data of Mbps, it is possible to transmit in the transmission band of 6 MHz of the cable.

By the way, in digital CS broadcasting, CS
With the increase in transmission output of, it has been considered to increase the data transmission rate by reducing the Viterbi code rate.
In such a case, there are the following problems in performing retransmission over a cable. That is, in this case, 64Q
If AM is used, the bandwidth exceeds 6 MHz, so it is necessary to perform modulation using multi-valued 128 QAM or 256 QAM. 1A, 1B and 1C
To 64 QAM, 128 QAM and 256, respectively.
4 shows a data array on a QI plane of a digital signal modulated by QAM.

When digital services other than digital CS broadcasting such as digital BS broadcasting and terrestrial digital broadcasting are started, 64QA is used in digital cable broadcasting for retransmitting those digital services.
It may be necessary to use a modulation scheme other than M.

Accordingly, the present invention is intended to enable a single digital receiver to accurately receive a plurality of types of digital broadcast signals having different modulation schemes, frequencies, and the like. FIG. 2 shows an example of the overall configuration of a digital cable broadcast receiving apparatus according to an embodiment of the present invention. A digital cable broadcast signal is input to a front end unit 2 via an input terminal 1 to which a coaxial cable of a digital cable broadcast network is connected. The front-end unit 2 selects a host processor 5 from the received signals.
A predetermined carrier is tuned based on the control information from.

Further, the front end unit 2 performs a demodulation process corresponding to the modulation process performed on the transmission side, and performs an error correction process according to the encoding process performed on the transmission side. The transport stream obtained by such processing is supplied to the transport unit 3. The transport unit 3 includes a descrambler 31, a demultiplexer 32, and the like. The descrambler 31
Based on the control information from the host processor 5, if the separated signal components have been subjected to scrambling on the transmitting side, descrambling is performed. By the descrambling process, an MPEG compression-encoded signal obtained by performing MPEG compression-encoding on video data and / or audio data to be viewed is restored.

The output of the descrambler 31 is supplied to a demultiplexer 32. The demultiplexer 32 outputs, from the output of the descrambler 31, the host processor 5
Based on the control information from, a necessary packet such as video data and / or audio is separated and extracted. By this processing, individual packets of a format called PES (Packetized Elementary Stream) related to a desired channel are separated from each channel multiplexed in the transport stream.

The MPEG-compressed video data and / or audio data of the separated channels obtained as a result of the above processing by the transport unit 3 are supplied to the MPEG decoding unit 4. The MPEG decoding unit 4 forms an analog video output by performing a decoding process or the like in accordance with a process performed on the transmission side based on control information from the host processor 5, and forms an audio output. The MPEG decoding unit 4 includes a video decoder 41, an audio decoder 42, an NTSC encoder 4
3. It has a D / A converter 44 and the like. Demultiplexer 3
The individual packets of the PES format separated by 2 are transmitted to the video decoder 41 and / or the audio data decoder 42.
Supplied to

The video decoder 41 performs a decoding process on the MPEG-compressed signal, and the decoded output is passed through the NTSC encoder 43 to form a reproduced video signal. This reproduced video signal is taken out via the output terminal 9. On the other hand, in the audio decoder 42, a digital audio signal is formed, and the digital audio signal is converted into an analog left and right channel reproduced audio signal through the D / A converter 20. This reproduced audio signal is extracted via the output terminal 10.

A reproduced video signal and a reproduced audio signal taken out through the output terminals 9 and 10 are supplied to, for example, an RF modulator (not shown), and the reproduced video signal and the reproduced audio signal are output from the RF modulator. The signal is RF-modulated to form a reproduced television signal, and the reproduced television signal is supplied to an antenna terminal of a television receiver.

As described above, the host processor 5, which controls each unit, the front end unit 2, the transport stream unit 3, and the MPEG decoding unit 4
They are connected by a bus and can exchange data bidirectionally. The host processor 5 is connected to an operation input unit 7 having various setting switches and numeric keys, and the setting information is supplied from the operation input unit 7. Therefore, the host processor 5 stores the setting information according to the operation state of the operation input unit 7 in the nonvolatile memory 6 and reads out the data stored in the nonvolatile memory 6 as needed to read the control information. Each part is centrally managed by supplying the control information to each part.

Next, the front end unit 2 will be described in more detail. The front end unit 2 includes a tuner 21,
It has a QAM demodulation circuit 22, an error correction circuit 23, and the like. The tuner 21 receives a digital cable broadcast signal supplied via the input terminal 1, selects a desired carrier from the received signal, and converts the selected carrier into an intermediate frequency signal. The intermediate frequency signal output from the tuner 21 is Q
The signal is supplied to the AM demodulation circuit 22. QAM demodulation circuit 22
Performs baseband digital data by subjecting the supplied intermediate frequency signal to QAM demodulation corresponding to the modulation performed on the transmission side.
Baseband digital data output from the QAM demodulation circuit 22 is supplied to an error correction circuit 23. The error correction circuit 23 performs an error correction process on the supplied digital data according to the encoding process performed on the transmission side. As an output of the error correction circuit 23, a transport stream output is formed.

More specifically, the transport stream output from the front end unit 2 is a bit string defined in the MPEG system and is composed of a set of fixed-length packets of 188 bytes. Each packet consists of a header, an adaptation field for adding additional information to a specific individual packet, and a payload indicating the contents of the packet (video / audio, etc.). The header is composed of 4 bytes, and is always synchronized at the beginning. Bytes are allocated, and PID (Packet) which is identification information of the packet is provided.
Control information such as ID), presence / absence of scrambling, and presence / absence of a subsequent adaptation field and payload are stored.

The descrambler 31 descrambles each packet based on the control information. Then, in the demultiplexer, necessary packets such as video / audio / data are separated and extracted. Each packet separated and extracted by the demultiplexer 32 is supplied to the MPEG decoding unit 4. The output of the descrambler 31 is taken out via the terminal 8 as a high-speed data output.

The tuning process according to the embodiment of the present invention will be described below. In general channel selection processing in digital CS broadcasting or the like, information necessary for channel selection called PSI (Program Specific Information) in a transport stream, particularly NIT (N
An information table called “etwork Information Table) is obtained. The PSI is composed of four types of tables, and each table is represented in a format called a section format in conformity with the MPEG system. In one of the four tables, the same content is multiplexed on all the carriers in one NIT, and the transmission parameters (polarization plane, carrier frequency, convolution rate, etc.) for each carrier and the all digital transmission A list of channels is described.

FIG. 3 is a flowchart showing an example of a channel selection processing procedure according to an embodiment of the present invention. In addition,
The processing shown in FIG. 3 is performed, for example, in the host processor 5. As a default value, the user inputs, via the operation input unit 7 or the like, a reception parameter capable of receiving a channel confirmed to be transmitted in digital cable broadcasting (step S).
1). Channel selection is performed according to the channel reception parameters input in step S1 (step S2). The NIT is separated and extracted from the transport stream related to the channel selected in step S2, and the NIT is stored in the nonvolatile memory 6 to complete the acquisition of the NIT (step S2).
3). Then, the image / sound display related to the selected channel is performed (step S4).

Thereafter, when the user operates the operation input unit 7 to give an instruction to change the channel, the NIT stored in the nonvolatile memory 6 is referred to and the reception parameter of the new channel related to the channel change is changed. Confirmation is made (step S6). Then, it is determined whether or not the reception parameter needs to be changed (step S7). If it is determined that the reception parameter needs to be changed, the process proceeds to step S8; otherwise, the process proceeds to step S8.
Move to 9. In step S8, the front end unit 2
, For example, the setting of a register in the host processor 5 is changed, and the process proceeds to step S9. In step S9, a tuning operation is performed based on the control information of the register whose setting has been changed or held in accordance with the determination result in step S7, and thereafter, the process proceeds to step S3.

With the above processing, the reception parameters are set for the front end unit 2 in accordance with the channel change. As a result, it is possible to accurately receive the digital cable broadcast signal in response to the channel change. For this reason, the user can seamlessly change the channel without being conscious of the change of the reception parameter. Unless the receiving side changes the receiving parameters such as the frequency, the NI
By referring to T repeatedly, accurate reception as described above is always possible. Therefore, as long as the reception parameter such as frequency is not changed on the transmission side, the default value input in step S1 is performed only once,
All channels can be received accurately. That is, steps S1 and S2 surrounded by a dotted line in FIG. 3 need only be performed once unless the receiving side changes the reception parameters such as the frequency.

When the power is turned off, the data of the image / sound display state of the predetermined channel in step S4 is stored in the nonvolatile memory 6 together with the NIT held in step S3, and the data is stored in the nonvolatile memory 6 when the power is turned on again. The data is read and the state is returned to the state at the time of the previous power-off, and the processing from step S4 is started.

If the transmitting side changes the reception parameter such as frequency for some reason, the user is notified of the change and a new default value corresponding to the change is input, that is, the new default value is input. Step S1 below
By performing step S2, it is possible to prevent the reception from becoming impossible.

Furthermore, since unused channels differ depending on the cable broadcasting service provider, it is assumed that the transmitted channels are unified depending on the service provider. In such a case, referring to FIG. When performing the above-described processing, any business can be handled.

FIG. 3 shows the case where the process goes to step S3 after step S9 and the NIT is acquired again. However, the process may go to step S4 after step S9. In this case, as in steps S1 and S2, step S3 may be performed only once unless the receiving side changes the reception parameters such as the frequency. Therefore, there is an advantage that the processing procedure is simplified. However, when the reception parameters related to some channels are changed during viewing, a new NIT cannot be obtained, and as a result, the default value input in step S1 is performed. There is also a problem that the number of times of performing may increase.

Next, another embodiment of the present invention will be described. The overall configuration of another embodiment of the present invention is the same as that of the above-described embodiment of the present invention. FIG. 4 shows an example of a channel selection processing procedure operation according to an embodiment of the present invention. Steps that perform the same processing as the respective steps in FIG. 3 are denoted by the same reference numerals. In steps S11, S12, S13, and S14, channel selection for acquiring an NIT is performed in the same manner as in the procedure shown in FIG. These steps surrounded by a dotted line need to be performed only once, unless the transmission side changes reception parameters such as the frequency on the transmitting side as in the case of FIG.

That is, as step S11, reception parameters such as frequency are initialized. As step S12, channel selection is performed. Further, the process proceeds to step S13, where it is determined whether or not channel selection has been properly performed. If the channel selection has been properly performed, the process proceeds to step S3. Otherwise, the process proceeds to step S14 to change the parameter.

That is, the reception parameters stored in a predetermined memory such as the nonvolatile memory 6 at the time of shipment, for example, are sequentially set in step S14. Then, the process proceeds to step S12, where channel selection is performed under the reception parameters set in step S14. here,
A predetermined memory such as the non-volatile memory 6 stores in advance a reception parameter as a combination of all frequencies and modulation schemes which are assumed to be used in digital cable broadcasting in the predetermined memory such as the non-volatile memory 6. It is memorized. By such processing, a search for an appropriate reception parameter is automatically performed until it is determined that the channel selection has been properly performed.

Each step after step S3 is the same as each step S in the embodiment of the present invention shown in FIG. That is, the process after it is determined that the channel selection has been properly performed is similar to the embodiment of the present invention, in which the NIT is acquired, and based on the acquired NIT, an operation such as a channel change is performed. An automatic tracking process is performed.

The other embodiment of the present invention has an advantage that the user does not need to input a default value (step S1) as compared with the above-described embodiment of the present invention. Due to circumstances and the like, it is necessary to assume a change in reception parameters in a wide range in advance. As a result, a predetermined memory such as the nonvolatile memory 6 having a large memory capacity is required, which hinders cost reduction. There is a problem that there is a possibility.

In one embodiment of the present invention and another embodiment of the present invention, 64-level QAM, 128-level QAM, and 256-level QAM are used as different modulation schemes.
A case has been described where a signal modulated by is supplied, but the present invention can also be applied to other modulation schemes.

The above-described embodiment of the present invention provides a digital signal using an error correction code of a digital CS broadcast signal configured as a concatenated code using a Reed-Solomon code as an outer code and a convolutional code as an inner code. However, the present invention can be applied to a case where a digital signal using other error correction codes is received. That is, the present invention can be applied to a case where a plurality of types of digital signals having different error correction coding methods are handled.

Further, one receiver is configured to have a function of performing both the operation in one embodiment of the present invention and the operation in another embodiment of the present invention,
One of these two types of operations may be selected as the channel selection mode.

[0045]

According to the present invention, a digital broadcast signal such as a digital cable broadcast signal can be received by a user input or by a trial and error selection from a plurality of reception parameters stored in a memory in advance. A reception parameter usable for the channel switching process is set in accordance with information on the reception parameter such as NIT acquired from the digital broadcast signal received under the reception parameter set in this manner. Parameter setting is performed automatically.

For this reason, for example, the frequency for each channel,
Even when reception parameters such as modulation schemes are different, a single digital receiver can accurately perform reception processing corresponding to all channels.

Further, the change of the reception parameters and the like accompanying the channel switching process are automatically performed according to the acquired MNIT and the like, and a seamless channel change is realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a modulation method in digital cable broadcasting.

FIG. 2 is a block diagram showing an example of the overall configuration of an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a channel selection process according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating a tuning process according to another embodiment of the present invention.

[Explanation of symbols]

2 front end unit 3 transport unit 5 host processor 6 nonvolatile memory 7 operation input unit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hirofumi Yuchi 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5C064 BA01 BB10 BC16 BC21 BC22 BC25 BD08 5K061 AA03 BB06 BB17 CC45 JJ07

Claims (8)

[Claims] 1. A receiving device for receiving a digital broadcast signal, a receiving means for receiving a supplied digital broadcast signal, and an input for inputting a reception parameter usable for receiving the digital broadcast signal as an initial setting value. Means for acquiring information on a reception parameter included in the digital broadcast signal received by the operation of the reception means under the initial setting value, and performing a channel switching process according to the acquired information on the reception parameter. The receiving device automatically sets the receiving parameters associated with the receiving device. 2. The receiving apparatus according to claim 1, wherein the digital broadcast signal is a digital cable broadcast signal in a digital cable broadcast for retransmitting a digital CS broadcast signal. 3. The digital broadcast signal according to claim 1, wherein the digital broadcast signal is a digital cable broadcast signal in a digital cable broadcast for retransmitting a digital CS broadcast signal, and the information on the reception parameter is NIT. Receiving device. 4. The information processing apparatus according to claim 1, wherein the acquired information on the reception parameters is stored in a predetermined storage unit, and the information on the reception parameters is read from the storage unit when the channel is switched. Receiving device. 5. The information according to claim 1, wherein the information relating to the reception parameters is stored in a predetermined storage means, and the information relating to the reception parameters is acquired from the digital broadcast signal each time the channel switching process is performed. A receiving device, characterized in that: 6. A receiving device for receiving a digital broadcast signal, a receiving means for receiving a supplied digital broadcast signal, and a plurality of types of reception parameters assumed to be usable for receiving the digital broadcast signal. And a memory for reading the reception parameters one by one from the memory,
If the digital broadcast signal is not properly received by the operation of the receiving means under the read reception parameters, the reception parameters are read out again from the memory and the operation of the reception means under the read reception parameters is performed. And if the digital broadcast signal is received properly,
A receiving apparatus characterized in that setting of a receiving parameter associated with a channel switching process is automatically performed in accordance with information on a receiving parameter included in the digital broadcast signal. 7. A receiving method for receiving a digital broadcast signal, comprising the steps of: inputting a receiving parameter usable for receiving a supplied digital broadcast signal as an initial setting value; A receiving step of receiving a broadcast signal; and a step of obtaining information on a reception parameter included in the digital broadcast signal received in the receiving step, wherein a channel is switched according to the obtained information on the reception parameter. A receiving method characterized in that setting of receiving parameters accompanying processing is automatically performed. 8. A receiving method for receiving a digital broadcast signal, comprising the steps of sequentially receiving one type of reception parameter from a memory storing a plurality of types of reception parameters assumed to be usable for receiving the digital broadcast signal. A reception parameter reading step of reading reception parameters; a reception trial step of performing a process for receiving the digital broadcast signal under the reception parameters read by the read step; a digital broadcast signal by the reception trial step It is determined whether or not the digital broadcast signal is accurately received, and if not correctly received, the method further includes a step of shifting to the reception parameter reading step again, and the digital broadcast signal is accurately received by the reception trial step. In the case, the above digital transmission Receiving method for according to the information relating to the received parameter, characterized in that it is automatically performed when Receive parameter associated with the switching process of channels included in.