KR100698283B1 - A method for OFDM multi-carrier modulating a digital broadcasting signal using the TDS-OFDM transmitter - Google Patents

Abstract

Disclosed is a method for multi-carrier modulation of an digital broadcast signal using an OMD transmitter. In the OMDDM multi-carrier modulation method, converting a serial TS stream signal subjected to error correction encoding into a parallel TS stream signal, and converting the parallel TS stream signal to the number of subcarriers in each mode corresponding to the allocated bandwidth of the OSDM signal. Cross-modulating the quadrature phases according to each other; obtaining inverse fast Fourier-transformed quadrature phase-modulated parallel TS stream signals to obtain an OFTDM multicarrier modulated OFTDM signal; Converting the signal to serial. The allocated bandwidth of the OMD signal is 8 MHz, and the number of subcarriers corresponding to the allocated bandwidth is determined to be one of 2,048, 4096, and 8192 according to the service mode and the reception environment. According to the service mode, channel state, and reception environment of the transmitted signal, an optimal transmission parameter can be obtained by selectively determining among the number of subcarriers corresponding to the allocated bandwidth of '2,048', '4,096', and '8,192'. .

Time Domain Synchronization, OSDM, Subcarrier, Multicarrier, Modulation, Service Mode

Description

A method for OFDM multi-carrier modulating a digital broadcasting signal using the TDS-OFDM transmitter}

1 is a block diagram showing an OFM transmitter performing general time domain synchronous transmission;

FIG. 2 is a block diagram illustrating a preferred embodiment of an UF DM transmitter to which an UF DM multicarrier modulation method for time domain synchronous transmission according to the present invention is applied;

3 is a graph illustrating an example of a multicarrier modulated OFM signal according to FIG. 2, and

FIG. 4 is a flowchart illustrating a preferred embodiment of an UFDM multicarrier modulation method of a digital broadcast signal using FIG. 2.

Explanation of symbols on the main parts of the drawings

100: FEC coding unit 120: serial / parallel conversion unit

140: quadrature phase modulation unit 160: IFFT unit

180: parallel / serial conversion part 200: GI insertion part

220: PN insert 240: molded filter

260: RF amplifier 280: antenna

In the method of multi-carrier modulation of the digital broadcast signal using the OMD transmitter, more specifically, the number of subcarriers, the frequency spacing between subcarriers, and the roll-off factor for shaping filtering according to the mode of the OFM signal The present invention relates to an FM multicarrier modulation method of a digital broadcast signal using an OMD transmitter which can increase the spectrum efficiency of an OMD signal.

In general, a broadcasting system of a high definition television (HDTV) can be roughly divided into an image encoder and a modulator. The video encoder compresses digital data of about 1 Gbps obtained from a high quality video source into data of 15 to 18 Mbps. The modulator transmits several tens of Mbps of digital data to the receiver through a limited band channel of 6 to 8 MHz. Digital high-definition television broadcasting adopts a terrestrial simultaneous broadcasting method using a channel of a very high frequency (VHF) / ultra high frequency (UHF) band allocated for conventional television broadcasting.

Modulation methods for such digital broadcasting include quadrature amplitude modulation (QAM) and residual side band (VSB) modulation. In Europe, Orthogonal Frequency Division Multiplexing (OFDM), a digital modulation method that achieves a dual effect of improving transmission speed per bandwidth and preventing interference, is adopted as the next generation high-definition television terrestrial broadcasting method.                         

The advantage of the UFDM signal is that the waveform of the UFDM signal is the same as White Gaussian Noise, so it is different from the PAL (Phase Alternation by Line) and SECAM (Sequential Couleur a Memoire) methods. Less interference than broadcast service Accordingly, in the OMD system, the modulation scheme may be different for each carrier, so that hierarchical transmission is possible.

In general, an OPM transmitter that transmits an OFM signal using Time Domain Synchronous (TDS) provides a service through an allocated frequency band. At this time, the frequency bandwidth allocated for the digital broadcasting such as the FM signal is 8MHz. The OPM transmitter rearranges the OFM signals formed on the frequency axis along the time axis, and guard interval (GI) and guard intervals to suppress interference between signals in front of the OFM signal formed along the time axis. Transmit by inserting synchronization information before.

FIG. 1 is a block diagram illustrating an OMD transmitter that performs general time domain synchronization (TDS) transmission. The time domain synchronous FM transmitter includes an inverse discrete fourier transform (IDFT) unit 10, a guard interval (GI) insert unit 20, a pseudo noise sequence (PN) insert unit 30, and a pulse shaping filter 40. Has

The IDFT unit 10 performs an Inverse Discrete Fourier Transform that rearranges the OFM signal formed based on frequency based on time. The GI insertion unit 20 inserts a guard interval for suppressing interference between neighboring OFM die symbols with respect to the OFM die signal in which the inverse discrete Fourier transform is performed in the IDFT unit 10. The PN insertion unit 30 inserts Pseudo Noise Sequence (PN) information into the OMD symbol in which the protection interval is inserted. The pseudo-noise string information is synchronization information for predicting synchronization and channel of the OMD signal received by the OMD receiver which receives the transmitted OMD signal. At this time, the PN insertion unit 30 generates a pulse wave corresponding to the OMD signal into which the pseudo noise string information is inserted.

The pulse shaping filter 40 has a roll-off factor in which the pulse wave is set so that the pulse wave corresponding to the OPM signal output from the PN inserting unit 30 is formed corresponding to the occupied bandwidth of the OMD signal allocated thereto. shaping filtering according to the factor). The molded filtered OMD signal is a high frequency amplified signal transmitted through the antenna 50.

On the other hand, the method proposed for inverse discrete Fourier transform in the IDFT unit 10 of the conventional time-domain synchronous FM transmitter is set to 3780 subcarriers, the frequency interval between the subcarriers to 2KHz. Therefore, there is a problem in that it cannot adaptively cope with the service mode and / or reception environment of the provided OMD signal. In addition, the guard interval inserting section 20 inserts a guard interval every 1/6, 1/9, 1/12, 1/20, and 1/30 of the block size of the signal output from the IDFT section 10, respectively. .

Accordingly, the occupied bandwidth of the broadcast signal for transmission occupies 7.56 MHz of the allocated 8 MHz, so that the roll-off factor for the allocated 8 MHz is approximately 0.0582. Therefore, the pulse shaping filter 40 requires a shaping filter of a sharp transmission band with a roll-off factor of 0.0582 in the 7.56 MHz occupying band of 8 MHz. When such sharp shaping filtering is performed, a ripple phenomenon appears on both sides of the signal passing through the pulse shaping filter 40. The signal including the ripple phenomenon is a signal that is distorted with respect to the original signal to be transmitted, and there is a problem in that a receiver that receives the distorted signal cannot recover the original signal.

As in the related art, if the roll-off factor for shaping filtering is set too small, the shaping filtered signal may suffer from jitter on the receiving side, thereby degrading reception performance.

In addition, when the IDFT unit 10 is used for the time domain synchronous transmission as in the related art, a circuit is required to design a circuit which can increase the calculation for the inverse discrete Fourier transform and process a complicated calculation. Accordingly, the conventional OMD transmitter has a problem in that the circuit becomes complicated for the inverse discrete Fourier transform and becomes complicated in hardware. In addition, the receiver for receiving the OMD signal transmitted in this manner also has a problem in that the complexity increases in hardware.

An object of the present invention for solving the above problems, the number of subcarriers according to the inverse discrete Fourier transform for the multi-carrier modulation is performed to transmit time-domain synchronous FM signal to the service mode and reception environment An object of the present invention is to provide a method for multi-carrier modulation of the OFM using a time domain synchronous OMD transmitter with adaptive parameters.

Another object of the present invention for solving the above problems, time to solve the hardware complex configuration by performing the Inverse Discrete Fourier Transform for the multi-carrier modulation is performed to transmit time-domain synchronous FM signal An aspect of the present invention is to provide a method for multimodal multicarrier modulation using a region synchronization OFM transmitter.

According to the present invention, the object of the present invention, in the FM multi-carrier modulation method of the digital broadcast signal using the FM transmitter, converting a serial TS stream signal subjected to error correction encoding to a parallel TS stream signal, Mutually orthogonal phase modulation of the parallel TS stream signal according to the number of subcarriers in each mode corresponding to the OSDM allocation bandwidth, and performing an inverse fast Fourier transform on the orthogonal phase modulated parallel TS stream signal to produce an OFM die-carrier modulated A step of obtaining an FM signal, and serially converting the OS signal of the inverse fast Fourier transformed parallel TS stream signal, are achieved by the method of multi-carrier modulation of the digital broadcast signal.

The allocation bandwidth of the OMD signal is 8 MHz, and the number of subcarriers according to the mode corresponding to the allocation bandwidth is determined to be one of 2,048, 4096, and 8192 according to the service mode and the reception environment.

In the present embodiment, the method for multi-carrier modulation of the digital broadcast signal may further include inserting a guard interval to suppress interference between the FM symbols of the inverse fast Fourier transformed OSF signal. At this time, the guard interval is inserted at intervals of any one of 1/4, 1/8, 1/16, and 1/32 of the bandwidth occupied by the subcarrier.

In the method of multimodal carrier modulation of the digital broadcasting signal of the present embodiment, inserting pseudo noise string information into an OMD signal with a guard interval inserted therein, and a roll-off factor for setting the OFM signal containing the pseudo noise string information. shaping filtering on the basis of r, and amplifying the shaping filtered OFM signal.

Preferably, the roll off factor r is a value in the range of 0.08 to 0.12.

Meanwhile, when the number of subcarriers corresponding to the allocated bandwidth is 8,192, the interval d between the subcarriers is a value within a range of '(1116 Hz ± a)'. When the number of subcarriers corresponding to the allocated bandwidth is 4,096, an interval d between subcarriers is a value within a range of '(1116 Hz ± a) × 2'. In addition, when the number of subcarriers corresponding to the allocated bandwidth is 2,048, the interval d between the subcarriers is a value within a range of (1116 Hz ± a) x 4. Here, a is an effective range of the interval d between subcarriers, and has a range of '0 Hz' to '100 Hz'.

에 의해 결정된다. Preferably, when the number of subcarriers corresponding to the allocated bandwidth is 8,192, the number N of subcarriers in the effective band including the OMD signal among the allocated bandwidths is expressed by Equation (1)

Determined by

에 의해 결정된다. Further, when the number of subcarriers corresponding to the allocated bandwidth is 4,096, the number N of subcarriers of the effective band including the OMD DM signal among the allocated bandwidths is expressed by Equation (5).

Determined by

에 의해 결정된다. Meanwhile, when the number of subcarriers corresponding to the allocated band is 2,048, the number N of subcarriers of the effective band including the OFM signal among the allocated bands is represented by Equation 2

Determined by

According to the present invention, a service mode of a signal transmitted from among '2,048', '4,096', and '8,192', that is, the range of the number of subcarriers corresponding to the effective band for fast Fourier transform, is the number of subcarriers corresponding to the allocated band. By selectively determining in accordance with the channel condition and the reception environment, an optimal transmission parameter can be obtained.

In addition, by varying the frequency interval and the roll-off factor between the subcarriers within a predetermined range and accordingly set the number of subcarriers, it is possible to reduce the ripple phenomenon on both sides of the signal to be transmitted and to Jitter can be prevented.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 is a block diagram illustrating a preferred embodiment of an OSDM transmitter to which an OSDM multicarrier modulation method for time domain synchronization transmission according to the present invention is applied.

The FM transmitter includes a forward error correction coding (FEC) coding unit 100, a serial / parallel conversion unit 120, a quadrature phase modulator 140, an inverse discrete fourier transform (IFFT) unit 160, and parallel / A serial converter 180, a GI (Guard Interval) inserter 200, a PN (Pseudo Noise Sequence) inserter 220, a shaping filter 240, and an RF (Radio Frequency) amplifier 260 are included.

The FEC coding unit 100 performs coding for correcting an error occurring in transmission on a broadcast signal to be transmitted.                     

The serial / parallel converter 120 converts a signal of a serial TS stream in which the error correction encoding is performed by the FEC encoder 100 into a parallel TS stream signal.

The quadrature phase modulator 140 performs quadrature phase modulation on each parallel TS stream signal output from the quadrature / parallel converter 120.

The IFFT unit 160 performs an inverse fast Fourier transform on the quadrature-phase modulated parallel TS stream signal in the quadrature phase modulator 140 to obtain the OMD DM multicarrier modulated subcarrier.

The parallel / serial converting unit 180 converts the inverse fast Fourier transformed parallel TS stream signal by the IFFT unit 160 to serial.

The GI inserting unit 200 is a protection interval for suppressing interference between neighboring OFM die symbols of the ODP DM multicarrier modulated OPM DM signal, which is a serial TS stream signal output from the parallel / serial converter 180. Insert the Guard Interval.

The PN inserting unit 220 inserts a pseudo noise sequence (PN) into the OMD signal in which the protection interval is inserted in the GI inserting unit 200. In this case, the pseudo noise sequence (PN) information is synchronization information for predicting synchronization and channel of the OMD signal received by the OMD receiver which receives the OMD signal transmitted.

The shaping filter 240 performs shaping filtering on the basis of the set roll-off factor of the OMD signal in which the pseudo noise string information is inserted in the PN insertion unit 220. As the shaped filter 240 according to the present embodiment, a root raised cosine (RRC) filter is applied.

The RF amplifier 260 high frequency amplifies the OPM signal filtered by the shaping filter 240 based on the roll-off factor. The high frequency amplified OMD signal is transmitted to the receiver through a channel through the antenna 280.

In this embodiment, by using the IFFT unit 160 for OMD DM multicarrier modulation of the TS stream signal, it is possible to reduce the amount of calculation necessary for OMD DM multiple carrier modulation. This simplifies the circuit design of the system and has the effect of being simplified in hardware.

In the modulation method of the OFM signal using the multi-carrier according to the present embodiment, a symbol string input in serial form is converted into parallel data in a predetermined block unit through the serial / parallel conversion unit 120, and the symbol is parallelized. The modulation scheme is multiplexed with different subcarrier frequencies. In this case, the multicarriers used are characterized by having orthogonality with each other. Orthogonality means a property in which the product of two carriers becomes '0', which is a requirement for using multiple carriers. The implementation of the OSF modulation method of this embodiment is performed by an Inverse Fast Fourier Transform (IFFT) on the transmitting side and a Fast Fourier Transform (FFT) on the receiving side.

In the present embodiment, the multicarrier modulated OPM signal is composed of multiple subcarriers, and each subcarrier has a very small band. Thus, the overall spectral shape of the OMD signal for the allocated band has a shape close to a rectangle. Therefore, the frequency efficiency is relatively higher than that of the signal transmission method using a single carrier.                     

On the other hand, in the OMD DM multicarrier modulation using the OMD DM transmitter of the present embodiment, three modes, '2,048', '4,096', and subcarriers applied to the Fast Fourier Transform according to the service mode and / or reception environment are used. Set to '8192'. That is, the number of subcarriers corresponding to the '8MHz' band allocated for broadcasting may be determined as '2,048', '4,096', and '8192'. Accordingly, in this embodiment, the roll-off factor r for shaping filtering and the frequency spacing d between the subcarriers are variably determined within a predetermined range, so that each of the '2,048', '4,096', and '8192' subcarriers is determined. The number of subcarriers in the effective band including the actual OFM signal is determined and used for multicarrier modulation.

In addition, according to the present embodiment, the GI inserting unit 200 inserts a guard interval into the serial OPM signal output from the parallel / serial converting unit 180, 1/4, 1 for an effective block in which subcarriers exist. It is preferable to insert at intervals of any one of / 8, 1/16, and 1/32.

3 is a graph illustrating an example of a multicarrier modulated OMD signal according to FIG. 2. In the drawing, the allocated bandwidth for the FM broadcast is '8MHz', the maximum effective bandwidth is '7.6MHz', and the guard band (GB) for protecting the effective band is '0.2MHz' on both sides, respectively. . In addition, the number of subcarriers of the OMD DM signal corresponding to the effective band is 'N', and the frequency interval between the subcarriers is 'd' Hz.

According to the present embodiment, the number of subcarriers corresponding to the allocated band '8 MHz' is set to '2,048', '4,096', and '8,192' according to the service mode, channel state, and reception environment, and applied to the effective band. Assuming that the number of subcarriers is 'N', the frequency interval between subcarriers is d, and the rolloff factor is 'r', the sum of the effective band and the guard band can be expressed as Equation 1 below.

The number of subcarriers for applying to this embodiment is determined by Equation 2 below. Summarizing [Equation 1] above,

In general, when the number of subcarriers corresponding to the allocated band is '8,192', the frequency interval d between the subcarriers for fast Fourier transform is applied to '1,116 Hz'. Let a be the effective range for the frequency interval d between subcarriers for fast Fourier transform. Then, when the number of subcarriers in the allocated band is '8,192', the range of the frequency interval d between the subcarriers may be represented as '(1116 Hz ± a)'. When the number of subcarriers in the allocated band is '4,096', the range of the frequency interval d between the subcarriers may be represented as '(1116 Hz ± a) × 2'. In addition, when the number of subcarriers in the allocated band is '2,048', the range of the frequency interval d between the subcarriers may be represented as '(1116 Hz ± a) × 4'. At this time, the range of the effective range a is preferably set to '0 Hz' to '100 Hz'.

In this embodiment, the range of the roll off factor r for shaping filtering through the RRC filter is determined within '0.08' to '0.12'.

Accordingly, when the number of subcarriers in the allocated band is 8,192 ', the number N of subcarriers corresponding to the effective bandwidth in which the multicarrier modulation of the OMD signal is performed may be expressed by Equation 3 below.

Accordingly, the range of the number of subcarriers in the effective band for 8,192 'subcarriers can be determined by substituting the maximum value and the minimum value for the rolloff factor r and the effective range a determined according to the present embodiment in Equation 3 above. have.

Meanwhile, when the number of subcarriers of the allocated bandwidth is 4,096 ', the number N of subcarriers corresponding to the effective bandwidth in which the multicarrier modulation of the OMD signal is performed may be expressed by Equation 4 below.

Therefore, in [Equation 4], the range of the number of subcarriers in the effective band for the 4,096 'subcarriers can be determined by substituting the maximum value and the minimum value for the rolloff factor r and the effective range a determined according to the present embodiment, respectively. have.

On the other hand, when the number of subcarriers of the allocated bandwidth is 2,048 ', the number N of subcarriers corresponding to the effective band in which the multicarrier modulation of the OMD signal is performed can be expressed by Equation 5 below.

Therefore, in [Equation 5], the range of the number of subcarriers in the effective band for the 2,048 'subcarriers can be determined by substituting the maximum value and the minimum value for the rolloff factor r and the effective range a determined according to the present embodiment, respectively. have.

Accordingly, the service mode and the channel state of the signal transmitted among the number of subcarriers corresponding to the allocated bandwidth, '2,048', '4,096', and '8,192', which ranges from the number of subcarriers corresponding to the effective bandwidth for the fast Fourier transform. And may be selectively applied and determined according to a reception environment. Therefore, an optimal transmission parameter can be obtained.

Preferably, when the channel state is a static channel that does not change over time, the number of subcarriers corresponding to the allocated band is determined as '8,192'. In addition, when the channel state is a dynamic channel that changes with time, it is preferable to determine the number of subcarriers corresponding to the allocated band as '2,048'.

FIG. 4 is a flowchart illustrating a preferred embodiment of an UFDM multicarrier modulation method of a digital broadcast signal using FIG. 2. The serial / parallel converter 120 converts the signal of the serial TS stream, which has been subjected to error correction encoding, by the FEC coding unit 100 into a parallel TS stream signal (S100). The quadrature phase modulator 140 performs quadrature phase modulation on each parallel TS stream signal output from the serial / parallel converter 120 (S120). The IFFT unit 160 performs an inverse fast Fourier transform on the orthogonal phase modulated parallel TS stream signal to obtain an UFDM multicarrier modulated subcarrier (S140). The parallel / serial converter 180 converts the inverse fast Fourier transformed parallel TS stream signal in series (S160).

The GI inserting unit 200 is a protection interval for suppressing interference between neighboring OFM die symbols of the ODP DM multicarrier modulated OFM die signal, which is a serial TS stream signal output from the parallel / serial converting unit 180. It is inserted (S180). The PN insertion unit 220 inserts a pseudo noise string PN into the OFM signal into which the protection interval is inserted (S200).

The shaping filter 240 performs shaping filtering on the basis of the set roll-off factor of the OFM signal into which the pseudo noise column information is inserted (S220). The RF amplifier 260 high frequency amplifies the shape-filtered OFM signal based on the roll-off factor (S240).

Accordingly, as the frequency interval between the subcarriers and the roll-off factor are variably set within a predetermined range and the number of subcarriers is set accordingly, the ripple phenomenon can be reduced on both sides of the signal to be transmitted and the received signal is received on the receiving side. Jitter can be prevented.

In addition, if the OMD signal is modulated using the multi-carrier modulation method of the present embodiment, performance may be improved in a single frequency network (SFN). Single frequency network means that one broadcasting broadcasts nationwide in one frequency. As a result, co-channel interference becomes very severe. The OMD signal to which the modulation scheme of the present embodiment is applied has a strong characteristic in such a single frequency network environment. Therefore, it is possible to increase the transmission performance of the OFM signal in a single frequency network environment.

According to the present invention, a service mode of a signal transmitted among '2,048', '4,096', and '8,192', which is the number of subcarriers corresponding to an effective bandwidth for fast Fourier transform, is the number of subcarriers corresponding to an allocated band. By selectively determining in accordance with the channel condition and the reception environment, an optimal transmission parameter can be obtained.

In addition, by varying the frequency interval and the roll-off factor between the subcarriers within a predetermined range and accordingly set the number of subcarriers, it is possible to reduce the ripple phenomenon on both sides of the signal to be transmitted and to Jitter can be prevented.

In the above described and illustrated with respect to the preferred embodiment of the present invention, the present invention is not limited to the specific preferred embodiment described above, without departing from the gist of the invention claimed in the claims in the art Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

Claims (17)

In the method of modulating the digital broadcasting signal using the FM transmitter, Converting the input stream signal subjected to error correction encoding into a parallel signal; Modulating the parallel signal according to the number of subcarriers in each mode corresponding to an allocated bandwidth of an OMD signal; Inverse Fourier transforming the modulated signal to obtain an OFM signal; And And converting in series the OFM signal, which is the inverse Fourier transformed parallel signal, The allocation bandwidth of the OMD signal is within 8 MHz, and the number of subcarriers according to the mode corresponding to the allocation bandwidth is included in at least one of the ranges of 1900 to 2100, 3900 to 4100, and 8000 to 8200. OPDM modulation method of a digital broadcast signal, characterized in that. delete The method of claim 1, And the allocated bandwidth is 8 MHz, and the number of the subcarriers according to the mode corresponding to the allocated bandwidth is at least one of 2,048, 4096, and 8192. The method of claim 3, And inserting a guard interval to suppress interference between the OMD die symbols of the ODP die signal which has been inversely transformed. The method of claim 4, wherein And the guard interval is inserted as much as one of 1/4, 1/8, 1/16, and 1/32 of the length of the FM signal. The method of claim 5, And inserting pseudo-noise string information into the OFM signal into which the protection interval is inserted. The method of claim 6, And shaping and filtering the OFM signal into which the pseudo-noise string information is inserted, based on a set rolloff factor r. The method of claim 7, wherein And the roll-off factor r is any one of values within a range of 0.08 to 0.12. The method of claim 8, When the number of subcarriers corresponding to the allocated bandwidth is 8,192, The interval d between the subcarriers is any one within a range of '(1116 Hz ± a)', and a is an effective range of the interval d between the subcarriers. The method of claim 9, When the number of subcarriers corresponding to the allocated bandwidth is 4,096, And an interval d between the subcarriers is one within a range of (1116 Hz ± a) × 2. The method of claim 10, When the number of subcarriers corresponding to the allocated bandwidth is 2,048, And an interval d between the subcarriers is any one within a range of '(1116 Hz ± a) × 4'. The method of claim 11, The effective range a is a range of '0Hz' to '100Hz' of the FM broadcast modulation method of the digital broadcast signal. The method of claim 12, When the number of subcarriers corresponding to the allocated bandwidth is 8,192, The number N of subcarriers of the effective band in which the OFM signal among the allocated bandwidth is determined by the following equation.

The method of claim 13, When the number of subcarriers corresponding to the allocated bandwidth is 4,096, The number N of subcarriers of the effective band in which the OMD DM signal is included among the allocated bands is determined by the following equation.

The method of claim 14, When the number of subcarriers corresponding to the allocated bandwidth is 2,048, The number N of subcarriers of the effective band in which the OFM signal among the allocated bandwidth is determined by the following equation.

The method of claim 15, And amplifying the molded-filtered FM signal by high frequency amplification. The method of claim 1, And a modulation method in the modulation step is quadrature phase modulation (QPSK) or quadrature amplitude modulation (QAM).

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