JP2003069525A - Digital broadcasting false signal generating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital broadcasting false signal generating method by which different waveform digital broadcasting false signals for respective channels are generated and tests adapted to actual situations are available. SOLUTION: In a random data generating/mapping means 21, for example, a carrier of the OFDM signal modulated into QPSK in random data is fetched out, and an IFFT means 22 computes the inverse Fourier transform of the carrier into the complex number time waveform data, and then guard interval is added by a guard interval adding means 23. A quad up sample means 25 computerizes a quad up sample processing, and then a quadrature modulation means 27 computerizes quadrature modulation and a spectrum limit means 28 eliminates out-of-band spectrum and creates the final OFDM signal. The OFDM signal is registered on the waveform bank part and stored in the high speed memory after given waveform data is selectively read out, and by being output, is transformed into a high frequency signal of the channel specified as sequential waveform data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast pseudo signal generation method for generating a digital broadcast pseudo signal in order to confirm the transmission performance of a terrestrial digital broadcast wave.

[0002]

2. Description of the Related Art Terrestrial digital (television) broadcasting (I
SDB-T: Terrestrial Integrated Services Digital
Broadcasting) is scheduled to start in 2003 in the Kanto, Kinki and Chukyo Wide Areas, and by 2006 in other areas.

Therefore, co-listening equipment, CATV transmission equipment,
For TV receivers and the like, devices that are compatible with transmission of terrestrial digital broadcast waves have already been studied and developed. That is,
The transmission path must transmit a plurality of terrestrial digital broadcast signals, and the receiver must receive a plurality of terrestrial digital broadcast signals and normally receive one target wave.
Therefore, finally, it is necessary to confirm the terrestrial digital broadcast wave transmission performance of actually receiving and transmitting a plurality of terrestrial digital broadcast waves, and a signal simulating the radio wave emission situation after the start of terrestrial digital broadcast is required.

In order to generate a plurality of digital terrestrial broadcasting waves that simulate the radio wave emission state after the start of digital terrestrial broadcasting, the following three methods are currently considered. (1) Prepare multiple terrestrial digital broadcast modulators.

(2) As shown in FIG. 12, one terrestrial digital broadcast modulator (OFDM (Orthogonal Frequency D
ivision Multiplex: Orthogonal Frequency Division Multiplexing Modulator) 1
Output of multiple RF converters (frequency converters)
2 is converted into the frequency of the set channel and output.

(3) The digital terrestrial test broadcasts issued by the Tokyo Pilot Experiment Council are received, converted into a plurality of frequencies by a plurality of frequency converters, and output.

[0007]

Although the confirmation test of the terrestrial digital broadcast wave transmission performance can be carried out by the above three methods, there are the following problems. The method (1) is the most ideal, but it is very expensive because a plurality of actual broadcasting modulators are used. Method (2) above is 1
Since the output of the terrestrial digital broadcasting modulator 1 is frequency-converted by the plurality of RF converters 2, the output signal becomes a plurality of synchronized signals of the same spectrum, that is, the same signals up to the timing and modulation of the symbols, and the terrestrial digital It will be different from the actual radio wave emission situation after broadcasting starts,
I can't test according to the actual situation. The above method (3) receives radio waves emitted in the air, and therefore has a problem that stability and C / N ratio (Carrier to Noise ratio) vary depending on the location.

The present invention has been made in order to solve the above problems, and can generate a digital broadcast pseudo signal having a different waveform for each channel, so that it is possible to perform a test according to the actual situation and to construct it at a low cost. It is an object to provide a digital broadcast pseudo signal generation method.

[0009]

A digital broadcast pseudo signal generating method according to the present invention uses QPSK based on random data.
Alternatively, a step of outputting a carrier of a QAM-modulated OFDM signal as complex number data, a step of performing an inverse Fourier transform on each of the carriers and outputting it as complex number time waveform data, and an OF of the time waveform data
The carrier waveform at the rear end of the DM symbol period is OF
A step of adding a card interval to the front end of the DM symbol, and an OF including the card interval
Removing the out-of-band spectrum of the DM signal,
Up-sampling the signal from which the out-of-band spectrum has been removed to a frequency of 4 times and extracting it through a 4 times up-sampling filter; quadrature modulating the output signal of the 4 times up-sampling filter; The out-of-band spectrum is removed from the modulated signal and extracted as a final OFDM signal, the step of registering the final OFDM signal in the waveform bank section, and the step of registering in the waveform bank section. Selecting an arbitrary waveform of the OFDM signal, and the OF of the selected waveform
And reading the DM signal, storing it in a high-speed memory, and repeatedly outputting it.

As described above, the QP is generated by the random data.
The carrier of the SK or QAM-modulated OFDM signal is extracted as complex number data, inverse Fourier transformed into complex number time waveform data, a guard interval is added, and 4 times up-sampling processing is performed, and then quadrature modulation is performed. The out-of-band spectrum is removed by the spectrum limiting process to create a final OFDM signal, which is the OF of the digital broadcast pseudo signal reference.
DM signals can be created. And the OFD
The M signal is registered in advance in the waveform bank section, the arbitrary waveform data registered in the waveform bank section is selectively read out and stored in the high speed memory, and the continuous waveform data is generated by repeatedly outputting from the high speed memory. can do.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a digital broadcast pseudo signal generating method according to the present invention. In FIG. 1, reference numeral 11 denotes an arbitrary waveform generator, which outputs 4 × 512/63 MHz (32.507) from the clock generator 12.
A clock of 936 ... MHz) is input. The arbitrary waveform generating section 11 generates an address for the waveform bank section 13 in synchronization with the clock, reads the waveform data from the waveform bank section 13 using this address, stores it in the internal high speed memory, and stores it in this high speed memory. The waveform data is repeatedly read and output to the IF converter 14 in the next stage.

The clock generator 12 has an oscillation element 17 for generating a 10 MHz clock, such as a crystal oscillator, inside, and the clock of the oscillation element 17 and an external reference signal of 10 MHz input from the outside can be arbitrarily set. It can be switched to and used.

The clock generator 12 outputs a clock signal based on an external reference signal of 10 MHz or an output signal of the oscillator 17.
× 512 / 63MHz (32.50936 ... MHz)
Clock and 512/63 + 37.15 MHz (45.
276984 ... MHz) and generates 4 × 51
A clock of 2/63 MHz (32.50936 ... MHz) is input to the arbitrary waveform generator 11 and 512/63 + 3.
A 7.15 MHz (45.276984 ... MHz) clock is input to the IF converter 14 as a local oscillation signal.

The waveform bank unit 13 has a plurality of memories, for example, 16 EPROMs, and each EPROM has digital broadcast pseudo signal waveform data, that is, OFDM (Orth).
Ogonal Frequency Division Multiplex) signals are registered in advance. The OFDM signal registered in each EPROM is ISDB-T (Terrestrial In
Integrated Services Digital Broadcasting: Compliant with the specifications of digital terrestrial broadcasting) and consists of multiple symbols modulated with random data. The method of generating the OFDM signal registered in each EPROM will be described in detail later. In addition, the 16 EPROs in the waveform bank unit 13
M can be selected by 16 waveform selection buttons provided on the front panel section 15. When the waveform selection button on the front panel section 15 is operated, the corresponding EPROM is selected, and the EPROM is addressed by the arbitrary waveform generation section 11 and the previously registered waveform data is read.

The arbitrary waveform generator 11 includes a waveform bank unit 13
After storing the waveform data read from the internal high-speed memory, it is repeatedly read from this high-speed memory, and the sequential D / A
Converted to a center frequency of 512/63 MHz (8.1269
(85 ... MHz) signal is generated and input to the IF converter 14. The IF converter 14 includes the arbitrary waveform generator 11
Center frequency of 512/63 MHz (8.1
26985 ... MHz) and the local oscillation frequency from the clock generator 12 is 512/63 + 37.15 MHz (4
(5.276984 ... MHz) signal to obtain 3
IF frequency centered around 7.15 MHz (intermediate frequency)
And is output to the RF converter 16.

Further, the RF converter 16 has 10 MH
An external reference signal of z and a channel setting signal are input. The RF converter 16 has a clock generation unit inside. This clock generation unit is similar to the clock generation unit 12 in FIG.
The required synchronous clock is generated by arbitrarily switching between the Hz clock and the externally input 10 MHz reference signal.

The RF converter 16 operates in synchronization with the synchronous clock generated by the internal clock generator, converts the IF signal input from the IF converter 14 into the frequency of the designated TV channel according to the channel setting signal, and digital broadcast. Output as a pseudo signal.

The channel setting in the RF converter 16, that is, the frequency of the carrier wave of cable television broadcasting using the frequency from 90 MHz to 770 MHz is from 93 MHz to 767 MHz, for example, 93 MH.
z, 99 MHz, 105 MHz, ..., 767 MHz
And a frequency set at intervals of 6 MHz, and 1/7 MHz (= 142.
857 ... kHz) and shifts to the higher side. The frequency band used by the standard system of digital broadcasting is 5.6 MHz. The RF converter 16 is capable of switching between the frequency specified by the above-mentioned Enforcement Regulations of the Cable Television Broadcast Law and the frequency without adding 1/7 MHz.

FIG. 2 shows the allowable range of the modulated wave spectrum of the carrier. For carrier frequency,
The relative attenuation amount at ± 2.79 MHz is 0 dB, ± 2.
The relative attenuation at 86 MHz is -20 dB, ± 3.0.
The relative attenuation at 0 MHz is -27 dB, ± 4.36.
The relative attenuation amount in MHz is -50 dB.

FIG. 3 shows each EPROM of the waveform bank unit 13.
2 shows a method of generating an OFDM signal to be registered in. The generation of this OFDM signal is performed by software processing. This software processing is performed by, for example, the random data generation / mapping means 21, IFFT.
It comprises means 22, guard interval adding means 23, spectrum limiting means 24, 4-fold up-sampling means 25, 4-fold up-sampling filter 26, quadrature modulation means 27, and spectrum limiting means 28.

The random data generation / mapping means 21 generates random data using a random function of numerical calculation software, for example. As a random function generation algorithm, for example, a linear congruential method is used. The random data generation / mapping means 21 uses the random data to generate Q data as shown in FIGS. 4 (a) and 4 (b).
It is AM-modulated or QPSK-modulated and output as a carrier of a digital broadcast pseudo signal. This carrier is output as complex number data (Re: real number, Im: imaginary number). FIGS. 4A and 4B show the mapping state of each carrier of the OFDM signal, and FIG. 4A shows 64QAM.
When modulation is performed, (b) is when QPSK modulation is performed.

The carrier output from the random data generating / mapping means 21 is an inverse Fourier transform (IF).
The FT) means 22 outputs the complex time waveform data.

After the time waveform is generated by the inverse Fourier transform means 22, the guard interval adding means 23 is used to generate the time waveform shown in FIG.
As shown in (a), the rear end A of each OFDM symbol period
The carrier waveform in is added to the front end B of the OFDM symbol as a card interval. FIG. 5B shows an example of a waveform when the guide interval is added. The length of the guard interval is, for example, 1/3.
It is preset to values such as 2, 1/16, 1/8, and 1/4.

Since the spectrum of the OFDM signal is widened by adding the guard interval, the spectrum LPM is removed by the spectrum limiting means 24 by the digital LPF. When the above digital LPF is used, for example, a Fourier transform (FFT) of an OFDM signal is performed.
Is converted into the frequency domain by, and the spectrum limitation is performed by setting the data of the unnecessary spectrum portion on the frequency axis data to “0”. The above processing simplifies the processing on the software and improves the processing speed.

The signal from which the out-of-band spectrum is removed by the spectrum limiting means 24 is 4 times up sampled by the sampling means 2
The frequency is upsampled to 4 times the frequency at 5 and taken out through the 4 times upsampling filter 26. This is a process for finally obtaining a signal having a center frequency of 512/63 MHz (8.126985 ... MHz).

Then, the quadrature modulation means 27 quadrature modulates the output signal of the 4 × up-sampling filter 26, that is, the baseband OFDM signal, to an IF frequency having a center frequency of 512/63 MHz (8.126985 ... MHz). Convert. The quadrature modulation means 27 has sin and
The cos signal is used as the signal of the local oscillation frequency and is quadrature modulated.

FIG. 6 shows a spectrum at the time of quadrature modulation. FIG. 6 (a) shows the arrangement of carriers in the FFT window, and FIG. 6 (b) shows the arrangement of carriers after quadrature modulation. ing. When quadrature modulation is performed by analog hardware, there is a problem that it is affected by DC offset, but by performing quadrature modulation by software as described above, the influence of DC offset can be reliably prevented.

Next, the out-of-band spectrum is removed from the quadrature-modulated signal by the spectrum limiting means 28, and the final OFDM time waveform signal is extracted.
It is registered in the waveform bank unit 13.

In the generation of the OFDM signal, the ISDB-
An OFDM parameter based on T is set, a plurality of types of waveform signals are generated, and registered in a plurality of EPROMs provided in the waveform bank unit 13. Therefore, the EPROM 13
By selecting 1, any waveform can be selected.

The OFDM parameters based on ISDB-T are carrier modulation methods: DPQSK, QPSK, 16QA.
M, 64QAM, Number of carriers: Mode 1: 1405 lines, Mode 2:
2809 lines, Mode3: 5617 lines, Guard interval: 1/32, 1/16, 1/8, 1
It is / 4. Further, the number of symbols is “31 symbols” when the guard interval is 1/32 in Mode 1,
When the guard interval is 1/4 in Mode 3, “6
Symbol ”.

The OFDM signal registered in the waveform bank unit 13 does not need to completely comply with ISDB-T, but by conforming to ISDB-T for Mode, FFT cycle, modulation method, and guard interval length, for example, the amplitude can be increased. The characteristics are similar to those of the ISDB-T OFDM signal.

FIG. 7 shows an example of parameter setting when 12 types of patterns are generated as OFDM signals to be registered in the EPROM of the waveform bank section 13. That is, three modes (Mode 1 to Mode)
3), two types of carrier modulation methods (QPSK, 64QA)
M), two guard intervals (1/32, 1/4)
Are combined to set 12 types of signal patterns.

EPROM in the waveform bank unit 13
If a 4 Mbit memory is used for the OFDM signal (Mode 1, guard interval 1/32), 31
You can output symbols.

Next, the processing of the spectrum limiting means 28 in FIG. 3 will be described in more detail. When an OFDM signal including a plurality of symbols is generated, the connection points A and B between the symbols become discontinuous as shown in FIG. 8 and the spectrum spreads, so that a plurality of symbols are connected. It is necessary to limit the bandwidth with.

In this embodiment, the OFDM signal consisting of a finite number of symbols registered in the waveform bank section 13 is read out to the arbitrary waveform generating section 11 and stored in the memory, and the finite number of symbols stored in this memory is repeatedly output. , Is processed by the spectrum limiting means 28 so that discontinuity does not occur at the beginning and end of the symbols.

Now, for example, as shown in FIG.
When the OFDM signal formed by connecting 8 symbols is filtered by the spectrum limiting means 28 as it is to limit the band, as shown in FIG. Although no seam occurs, the end symbol 28 and the top symbol 1 are discontinuous.

In order to eliminate such an inconvenience, in the present embodiment, first, the spectrum limiting means 28 will be described with reference to FIG.
As shown in 0 (a), the same symbol as the last symbol 28 is added before the first symbol 1, and the same symbol as the first symbol 1 is added after the last symbol 28. When the band is limited by performing the filter processing in this state, the joint between the symbols 1 to 28 is eliminated as shown in FIG. 10B, and the symbol 1 at the beginning and the symbol 28 added before it are And the joint between the trailing symbol 28 and the symbol 1 added thereafter is lost. In this state, FIG. 10 (c)
When the symbol 28 added to the head and the symbol 1 added to the end are removed as shown in (4), the end symbol 28 and the head symbol 1 are smoothly continuous.

O which has been subjected to the above-described spectrum limiting treatment
When the FDM signal is registered in each EPROM of the waveform bank unit 13, even if the arbitrary waveform generation unit 11 stores the OFDM signal read from the waveform bank unit 13 in the memory and repeatedly outputs it, the end symbol 28 and the start symbol 1 A smooth continuous state is maintained between and.

FIG. 11 shows the frequency spectrum of the output signal from the arbitrary waveform generator 11, where (a) is the spectrum limiting means 28 when the discontinuity is not filtered, and (b) is shown. Shows the case where the discontinuity is filtered. FIG. 11 (a)
Although the out-of-band spectrum is generated in, the figure shows that the out-of-band spectrum is sufficiently removed. By performing the processing of the spectrum limiting means 28, it is possible to smoothly connect without a joint between a plurality of symbols and surely remove the out-of-band spectrum.

[0040]

As described above in detail, according to the present invention, a carrier of an OFDM signal QPSK or QAM modulated by random data is taken out as complex number data and inverse Fourier transformed to complex number time waveform data.
A digital broadcasting pseudo signal is created by adding a guard interval, performing up-sampling by 4 times, and then performing quadrature modulation and removing the out-of-band spectrum by spectrum limitation processing to create the final OFDM signal. It is possible to create an OFDM signal that serves as a reference of. Then, the OFDM signal is registered in advance in the waveform bank section, the registered arbitrary waveform data is selectively read out and stored in the high-speed memory, and is repeatedly output from the high-speed memory to generate continuous waveform data. be able to. Furthermore, by converting this continuous waveform data into a high frequency signal of a designated channel, a digital broadcast pseudo signal of an arbitrary channel can be generated. Therefore, it is possible to generate a digital broadcast pseudo signal having a different waveform for each channel, to perform a test according to an actual situation, and to use an actual broadcast modulator, so that the configuration can be inexpensive.

Further, when the out-of-band spectrum is removed from the quadrature-modulated signal and the final OFDM signal is taken out, the same symbol as the end is added before the head symbol forming the OFDM signal. In addition, after adding the same symbol as the beginning after the ending symbol, the out-of-band spectrum is removed by filtering, and then the OFDM signal from which the out-of-band spectrum is removed is added to the beginning and end. Since the added symbols are removed, even when the OFDM signal is repeatedly output, it is possible to smoothly connect without a joint between a plurality of symbols and reliably remove the out-of-band spectrum.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a digital broadcast pseudo signal generating method according to an embodiment of the present invention.

FIG. 2 is a diagram showing an allowable range of a modulated wave spectrum of a carrier in the same embodiment.

FIG. 3 is an O registered in the waveform bank unit in the same embodiment.
The figure which shows the generation method of an FDM signal.

FIG. 4A is an OFD when 64QAM modulation is performed.
The figure which shows the mapping state of each carrier of M signal, (b)
FIG. 4 is a diagram showing a mapping state of each carrier of an OFDM signal when QPSK modulation is performed.

5A is a diagram for explaining a processing operation when a guard interval is added, and FIG. 5B is a diagram showing an example of a waveform when a guard interval is added.

FIG. 6 is a diagram showing a spectrum at the time of quadrature modulation.

FIG. 7 is a diagram showing a parameter setting example of an OFDM signal registered in a waveform bank unit.

FIG. 8 is a waveform diagram showing a discontinuous state between symbols when a plurality of symbols are connected.

FIG. 9 is a diagram showing a connection state between symbols when a normal filter process is performed on an OFDM signal formed by connecting a plurality of symbols.

FIG. 10 is a diagram showing a connection state between symbols when the filter processing of the present invention is performed on an OFDM signal formed by connecting a plurality of symbols.

11 is a diagram showing a frequency spectrum when the discontinuity portion is not filtered by the spectrum limiting means, and FIG. 11B is a frequency spectrum when the discontinuity portion is filtered. Fig.

FIG. 12 is a diagram showing an example of creating a conventional terrestrial digital broadcast signal.

[Explanation of symbols]

11 ... Arbitrary waveform generator 12 ... Clock generation unit 13 ... Waveform bank section 14 ... IF converter 15 ... Front panel 16 ... RF converter 17 ... Oscillation element 21. Random data generation / mapping means 22 ... Inverse Fourier transform means 23 ... Guard interval adding means 24 ... Spectrum limiting means 25 ... 4 times up sampling means 26 ... 4 times up sample filter 27 ... Quadrature modulation means 28 ... Spectrum limiting means

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 2, 2002 (2002.5.2)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

A digital broadcast pseudo signal generating method according to the present invention uses QPSK based on random data.
Alternatively, a step of outputting a carrier of a QAM-modulated OFDM signal as complex number data, a step of performing an inverse Fourier transform on each of the carriers and outputting it as complex number time waveform data, and an OF of the time waveform data
The carrier waveform at the rear end of the DM symbol period is OF
A step of adding a guard interval to the front end of the DM symbol, and an OF including the guard interval
Removing the out-of-band spectrum of the DM signal,
Up-sampling the signal from which the out-of-band spectrum has been removed to a frequency of 4 times and extracting it through a 4 times up-sampling filter; quadrature modulating the output signal of the 4 times up-sampling filter; The out-of-band spectrum is removed from the modulated signal and extracted as a final OFDM signal, the step of registering the final OFDM signal in the waveform bank section, and the step of registering in the waveform bank section. Selecting an arbitrary waveform of the OFDM signal, and the OF of the selected waveform
And reading the DM signal, storing it in a high-speed memory, and repeatedly outputting it.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

After the time waveform is generated by the inverse Fourier transform means 22, the guard interval adding means 23 is used to generate the time waveform shown in FIG.
As shown in (a), the rear end A of each OFDM symbol period
Gas carrier waveform at a front end B of the OFDM symbol in
Add as a time interval . Figure 5 (b) shows the gar
7 shows an example of a waveform when a dead interval is added. The length of the guard interval is, for example, 1/3.
It is preset to values such as 2, 1/16, 1/8, and 1/4.

Claims (3)

[Claims] 1. A step of outputting a carrier of an OFDM signal QPSK- or QAM-modulated by random data as complex number data, a step of inverse Fourier transforming each carrier and outputting as complex number time waveform data, and the time. Adding a carrier waveform at the rear end of the OFDM symbol period to the front end of the OFDM symbol as a card interval for the waveform data; up-sampling the OFDM signal with the added card interval to a frequency four times higher; Quadrature-modulating the upsampled OFDM signal, removing out-of-band spectrum from the quadrature-modulated signal, and extracting as a final OFDM signal; and waveform banking the final OFDM signal. The steps to register with OF registered in the waveform bank section
A method for generating a pseudo signal for digital broadcasting, comprising: a step of selecting an arbitrary waveform of a DM signal; and a step of reading the OFDM signal of the selected waveform, storing the OFDM signal in a high-speed memory and repeatedly outputting the same. 2. A step of outputting a carrier of an OFDM signal QPSK- or QAM-modulated by random data as complex number data, a step of performing an inverse Fourier transform of each carrier and outputting as complex number time waveform data, and the time. Adding a carrier waveform at the rear end of the OFDM symbol period to the front end of the OFDM symbol as a card interval with respect to the waveform data; removing an out-of-band spectrum of the OFDM signal to which the card interval has been added; Up-sampling the signal from which the out-of-band spectrum is removed to a frequency of 4 times and extracting it through a 4 times up-sampling filter; quadrature modulating the output signal of the 4 times up-sampling filter; Out-of-band scan for later signals Removal of the vector and final OF
Extracting as a DM signal, and the final OF
Registering the DM signal in the waveform bank section, selecting an arbitrary waveform of the OFDM signal registered in the waveform bank section, reading the OFDM signal of the selected waveform, storing it in a high-speed memory, and repeatedly outputting it A method for generating a pseudo signal for digital broadcasting, comprising: 3. The step of removing the out-of-band spectrum from the quadrature-modulated signal and extracting it as a final OFDM signal includes adding the same symbol as the end to the beginning of the symbol forming the OFDM signal. In addition, the step of adding the same symbol as the beginning after the last symbol, the step of filtering the OFDM signal to which the symbol is added to remove the out-of-band spectrum, and the removal of the out-of-band spectrum 3. The method for generating a pseudo signal for digital broadcasting according to claim 1, further comprising the step of removing symbols added to the beginning and the end of the OFDM signal.