Modulator

Abstract

This modulator includes: a first energy distribution unit whereby a signal wave to be transmitted is distributed at a first ratio corresponding to a desired level for each side wave component; an even term side wave generation unit whereby one or more signals that have an even-numbered side wave component are generated on the basis of a carrier signal and the signal wave distributed at the first ratio by the first energy distribution unit; and an odd term side wave generation unit whereby one or more signals that have an odd-numbered side wave component are generated on the basis of the carrier signal and the signal wave distributed at the first ratio by the first energy distribution unit.　

Description

Modulator

[0001] This application claims priority to PCT / JP2024 / 24636 filed in Japan on July 8, 2024, the contents of which are incorporated herein by reference.

[0002] Conventionally, an Armstrong modulator has been used as a modulator. The Armstrong modulator has a simple configuration and displaces the phase or frequency of a carrier wave. That is, the Armstrong modulator performs phase modulation or frequency modulation. FIG. 18 is a diagram showing an example of the configuration of a modulator 90 of the prior art. The modulator 90 is an example of an Armstrong modulator configured as a phase modulator, and a phase adjustment unit is arranged at the input section of the signal wave.

[0003] The modulator 90 includes a carrier signal generating unit 91, a dividing unit 92, a phase adjusting unit 93, a phase adjusting unit 94, a multiplier 95, and a combiner 96. The carrier signal generating unit 91 outputs a carrier signal. The divider 92 divides the carrier signal output by the carrier signal generating unit 91 into two. One of the divided carrier signals is input to the phase adjusting unit 93. The phase adjusting unit 93 performs a phase rotation of 90 degrees on the input carrier signal and then outputs the phase to the multiplier 95. Here, the phase adjusting unit 93 may be configured to be disposed between the dividing unit 92 and the multiplier 95 as shown in FIG. 18 , or may be disposed between the dividing unit 92, which is the output of the other dividing unit 92, and the combiner 96. When the phase adjusting unit 93 is disposed between the dividing unit 92 and the combiner 96, the phase rotation in the phase adjusting unit 93 is minus 90 degrees. The phase adjustment unit 94 rotates the phase of the input carrier signal by 90 degrees and then outputs the result to the multiplication unit 95. The multiplication unit 95 multiplies the phase-rotated carrier signal by the phase-rotated signal wave, and outputs the multiplied signal to the combination unit 96. The combination unit 96 outputs a signal obtained by combining the signal output from the multiplication unit 95 with the other carrier signal distributed by the distribution unit 92.

[0004] Toshiaki Shimoba and four others, "Study on a wideband RF signal transmission system using an FM batch conversion method with all-channel phase modulation," 2021 Institute of Electronics, Information and Communication Engineers General Conference

[0005] In a conventional modulator 90, the output signal from a carrier signal generator 91 is split into two, one of which is phase-shifted by 90 degrees using a phase adjuster (phase adjuster 93), and then this signal is multiplied by a signal wave in a multiplier (multiplier 95).The signal multiplied by the multiplier is then added to the other split output signal to obtain a pseudo carrier signal and a first sideband signal.With this configuration, it is not possible to obtain second or subsequent sideband components.

[0006] An ideal phase modulation signal waveform has first and subsequent sidewave components (second, third, fourth, etc., in FIG. 19 ), as shown in FIG. 19 . In other words, a missing sidewave indicates a deterioration in the distortion characteristics of the signal. Thus, conventional Armstrong modulators have had the problem of degraded distortion characteristics.

[0007] In view of the above circumstances, an object of the present invention is to provide a technique capable of suppressing deterioration of distortion characteristics of a modulated output signal.

[0008] One aspect of the present invention is a modulator comprising: a first energy divider that divides a signal wave to be transmitted at a first ratio corresponding to a desired level for each sideband component; an even-term sideband generation unit that generates one or more signals having even-numbered sideband components based on a carrier signal and the signal wave divided at the first ratio by the first energy divider; and an odd-term sideband generation unit that generates one or more signals having odd-numbered sideband components based on the carrier signal and the signal wave divided at the first ratio by the first energy divider.

[0009] According to the present invention, it is possible to suppress deterioration of the distortion characteristics of the modulated output signal.

[0010] 1 is a configuration diagram of a modulator. FIG. 1 is a configuration diagram of a modulator in a first embodiment. FIG. 2 is a diagram for explaining an ideal PM signal waveform according to a value of modulation index β in the first embodiment. FIG. 3 is a diagram showing an example of a power table held by an information output unit in the first embodiment. FIG. 4 is a diagram for explaining the mechanism of an energy distribution unit in the first embodiment. FIG. 5 is a configuration diagram of a modulator in a second embodiment. FIG. 6 is a flowchart showing a processing flow of an initial adjustment operation performed by a modulator in the second embodiment. FIG. 7 is a diagram showing an example of a table used in the initial adjustment operation performed by a modulator in the second embodiment. FIG. 8 is a diagram showing an example of a table used in the initial adjustment operation performed by a modulator in the second embodiment. FIG. 9 is a configuration diagram of a modulator in a third embodiment. FIG. 10 is a configuration diagram of a modulator in a fourth embodiment. FIG. 11 is a flowchart showing a processing flow of an initial adjustment operation performed by a modulator in the fourth embodiment. FIG. 12 is a diagram showing an example of a table used in the initial adjustment operation performed by a modulator in the fourth embodiment. FIG. 13 is a diagram showing an example of a table used in the initial adjustment operation performed by a modulator in the fourth embodiment. FIG. 14 is a diagram showing an example of a table used in the initial adjustment operation performed by a modulator in the fourth embodiment. FIG. 1 is a diagram illustrating an example of an ideal signal waveform of a phase modulation method.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] (Configuration of the embodiment) Before describing a specific configuration of the present invention, one configuration assumed to solve the problems of the present invention will be described. Fig. 1 is a configuration diagram of a modulator 10. The modulator 10 includes a carrier signal generating unit 101, a dividing unit 102, a phase adjusting unit 103, a dividing unit 104, a level adjusting unit 105, a dividing unit 106, a dividing unit 107, a phase adjusting unit 108, a dividing unit 109, a dividing unit 110, a dividing unit 111, an odd-term sideband generating unit 112, an even-term sideband generating unit 113, and a multiplexing unit 114.

[0013] The carrier signal generating unit 101 outputs a carrier signal. The dividing unit 102 inputs the carrier signal output by the carrier signal generating unit 101. The dividing unit 102 divides the input carrier signal. For example, the dividing unit 102 divides the input carrier signal into two. In this case, the dividing unit 102 divides the carrier signal into a first path and a second path. The phase adjusting unit 103 is connected to the first path divided by the dividing unit 102, and the dividing unit 104 is connected to the second path divided by the dividing unit 102. The carrier signal divided by the dividing unit 102 is input to the phase adjusting unit 103 and the dividing unit 104.

[0014] The distribution unit 104 receives the carrier signal distributed by the distribution unit 102. The distribution unit 104 distributes the received carrier signal. For example, the distribution unit 104 distributes the received carrier signal into two paths. In this case, the distribution unit 104 distributes the carrier signal to a first path and a second path. The level adjustment unit 105 is connected to the first path distributed by the distribution unit 104, and the distribution unit 110 is connected to the second path distributed by the distribution unit 104. The carrier signal distributed by the distribution unit 104 is input to the level adjustment unit 105 and the distribution unit 110.

[0015] The level adjustment unit 105 adjusts the level of the input carrier signal and outputs the level-adjusted carrier signal to the multiplexer 114. The level adjustment unit 105 is realized by, for example, a power amplifier or an attenuator.

[0016] The phase adjustment unit 103 receives the carrier signal distributed by the distribution unit 102. The phase adjustment unit 103 adjusts the phase of the input carrier signal. For example, the phase adjustment unit 103 rotates the phase of the input carrier signal by 90 degrees. The carrier signal whose phase has been adjusted by the phase adjustment unit 103 is input to the distribution unit 106.

[0017] Here, the phase adjustment unit 103 uses a phase shifter to rotate the phase of the input signal by 90 degrees (for example, if the carrier signal is cos, it is changed to sin), but it does not have to be a phase shifter as long as it is a device that can adjust the phase, and for example, a delay device may be used, or an implementation in which the phase is changed by 90 degrees by adjusting the wiring path length may be used. This is not limited to the phase adjustment unit 103, but is similar to the phase adjustment unit 108.

[0018] The dividing unit 106 receives the carrier signal whose phase has been adjusted by the phase adjusting unit 103. The dividing unit 106 divides the received phase-adjusted carrier signal into two or more paths. The carrier signals divided by the dividing unit 106 are input to the odd-term sideband generating unit 112.

[0019] The dividing unit 107 inputs a signal wave. The signal wave is a signal to be transmitted. The dividing unit 107 divides the input signal wave. For example, the dividing unit 107 divides the input signal wave into two. In this case, the dividing unit 107 divides the signal wave into a first path and a second path. A phase adjustment unit 108 is connected to the first path divided by the dividing unit 107, and a dividing unit 109 is connected to the second path divided by the dividing unit 107. The signal wave divided by the dividing unit 107 is input to the phase adjustment unit 108 and the dividing unit 109.

[0020] The phase adjustment unit 108 receives the signal wave distributed by the distribution unit 107. The phase adjustment unit 108 adjusts the phase of the input signal wave. For example, the phase adjustment unit 108 rotates the phase of the input signal wave by 90 degrees. The signal wave whose phase has been adjusted by the phase adjustment unit 108 is input to the distribution unit 111.

[0021] The dividing unit 111 receives the signal wave whose phase has been adjusted by the phase adjusting unit 108. The dividing unit 111 divides the input signal wave into two or more paths. The signal wave divided by the dividing unit 111 is input to the odd-term sideband generating unit 112.

[0022] The odd-term sidewave generating unit 112 generates odd-term sidewaves. The odd-term sidewaves are odd-numbered upper and lower sidewaves, such as the first upper sidewave (+J1), the first lower sidewave (-J1), the third upper sidewave (+J3), the third lower sidewave (-J3), .... The odd-term sidewave generating unit 112 is composed of one or more multipliers 120, one or more multiplier units 121, and one or more level adjuster units 122.

[0023] For example, if the odd-term sidewave generating unit 112 is to generate odd-numbered sidewaves up to the third sidewave (for example, the first and third sidewaves), the odd-term sidewave generating unit 112 is provided with two multipliers 120, two multipliers 121, and two level adjusters 122. Note that the multiplier 120-1 (multiplier (1x) in FIG. 1 ), which multiplies the frequency of a signal wave and outputs it, does not have to be provided because it is configured to output the input signal without any processing. In this case, the odd-term sidewave generating unit 112 is provided with one multiplier 120, and two multipliers 121 and two level adjusters 122.

[0024] Multiplier 120 converts each of the signal waves distributed by distributor 111 to a different odd multiple (n times) of frequency and outputs the converted signal waves. For example, if three multipliers 120 (N=3) are provided, multiplier 120-1 converts the signal waves distributed by distributor 111 to a frequency of 1 and outputs the converted signal waves, multiplier 120-2 converts the signal waves distributed by distributor 111 to a frequency of 3 and outputs the converted signal waves, and multiplier 120-3 converts the signal waves distributed by distributor 111 to a frequency of 5 and outputs the converted signal waves. Here, n is an odd number greater than or equal to 1.

[0025] The multiplier 121 multiplies the signal wave with n times the frequency output from the multiplier 120 by the carrier signal distributed by the distributor 106. The multiplier 121 outputs the signal obtained by the multiplication to the level adjuster 122.

[0026] The level adjustment unit 122 adjusts the level of the input signal. The level adjustment unit 122 outputs the level-adjusted signal to the multiplexing unit 114. The level adjustment unit 122 is realized by, for example, a power amplifier or an attenuator. The level adjustment unit 122 is one aspect of a second level adjustment unit.

[0027] The dividing unit 109 receives the signal wave divided by the dividing unit 107. The dividing unit 109 divides the received signal wave into two or more paths. The signal wave divided by the dividing unit 109 is input to the even-term sideband generating unit 113.

[0028] The dividing unit 110 receives the carrier signal divided by the dividing unit 104. The dividing unit 110 divides the received carrier signal into two or more paths. The carrier signal divided by the dividing unit 110 is input to the even-term sideband generating unit 113.

[0029] The even-term sidewave generating unit 113 generates even-term sidewaves. The even-term sidewaves are even-numbered upper and lower sidewaves, such as the second upper sidewave (+J2), the second lower sidewave (-J2), the fourth upper sidewave (+J4), the fourth lower sidewave (-J4), .... The even-term sidewave generating unit 113 is composed of one or more multipliers 130, one or more multiplier units 131, and one or more level adjuster units 132.

[0030] For example, if the even-term sideband generating unit 113 is to generate even-numbered sidebands up to the fourth sideband (e.g., the second sideband and the fourth sideband), the even-term sideband generating unit 113 includes two multipliers 130, two multipliers 131, and two level adjusters 132.

[0031] Multiplier 130 converts each of the signal waves distributed by distributor 109 into a different even multiple (m times) of the frequency and outputs the converted signal waves. For example, if three multipliers 130 are provided, multiplier 130-1 converts the signal waves distributed by distributor 109 into signals with double the frequency and outputs them, multiplier 130-2 converts the signal waves distributed by distributor 109 into signals with quadruple the frequency and outputs them, and multiplier 130-3 converts the signal waves distributed by distributor 109 into signals with six times the frequency and outputs them, where m is an even number greater than or equal to 2.

[0032] The multiplier 131 multiplies the signal wave with m times the frequency output from the multiplier 130 by the carrier signal distributed by the distributor 110. The multiplier 131 outputs the signal obtained by the multiplication to the level adjuster 132.

[0033] The level adjustment unit 132 adjusts the level of the input signal and outputs the level-adjusted signal to the multiplexing unit 114. The level adjustment unit 132 is realized by, for example, a power amplifier or an attenuator.

[0034] The multiplexer 114 multiplexes the signal output from the level adjuster 105 , the signals output from the odd-term sideband generator 112 , and the signals output from the even-term sideband generator 113 .

[0035] The spectrum of a phase-modulated waveform (PM waveform) (such as the waveform shown in FIG. 19 ) is uniquely determined once parameters such as the modulation index are determined, and the amplitude of each sideband is also uniquely determined. Therefore, as an example of a level adjustment method in each of the level adjustment units 105, 122, and 132 in the above-described embodiment, each of the level adjustment units 105, 122, and 132 adjusts the level so that it is equal to the magnitude of the ideal amplitude component of each sideband.

[0036] (Operation of Modulator) With the above configuration, the modulator 10 operates as follows. In explaining the operation of the modulator 10, it is assumed that the carrier signal generated by the carrier signal generating unit 101 is f ｃ = A ｃ cos(ω ｃ t), and the signal wave is f ｓ = cos(ω ｓ t).

[0037] The carrier signal generating section 101 of the modulator 10 generates a carrier signal f ｃ = A ｃ cos(ω ｃ t) is output from the carrier signal generating unit 101. ｃ = A ｃ cos(ω ｃ t) is divided by the dividing unit 102 and input to the phase adjusting unit 103 and dividing unit 104. The carrier signal f ｃ = A ｃ cos(ω ｃ t) is distributed by the distribution unit 104 and input to the level adjustment unit 105 and distribution unit 110.

[0038] The level adjustment unit 105 adjusts the input carrier signal f ｃ = A ｃ cos(ω ｃ t) and outputs it. For the sake of simplicity, the output of the level adjustment unit 105 may be expressed as [A]. That is, [A] = signal K ０ cos(ω ｃ t). Note that K ０ represents the amplitude after adjustment. ０ cos(ω ｃ t) corresponds to the carrier wave (J0).

[0039] The phase adjustment unit 103 adjusts the phase of the input carrier signal f ｃ = A ｃ cos(ω ｃ t) by rotating the phase of the carrier signal f ｃ =-A ｃ sin(ω ｃ t) by the phase adjustment unit 103. ｃ =-A ｃ sin(ω ｃ t) is distributed by the distributor 106 and input to each multiplier 121 of the odd-term sideband generating unit 112. For example, if the odd-term sideband generating unit 112 includes three multipliers 121, the distributor 106 divides the carrier signal f ｃ =-A ｃ sin(ω ｃ t) to three paths leading to the three multipliers 121. As a result, each multiplier 121 receives a carrier signal f ｃ =-A ｃ sin(ω ｃ t) is input.

[0040] The carrier signal f input to the distribution unit 110 ｃ = A ｃ cos(ω ｃ t) is distributed by the distributor 110 and input to each multiplier 131 of the even-term sideband generating unit 113. For example, if the even-term sideband generating unit 113 includes three multipliers 131, the distributor 110 divides the carrier signal f ｃ = A ｃ cos(ω ｃt) to three paths leading to the three multipliers 131. As a result, each multiplier 131 receives a carrier signal f ｃ = A ｃ cos(ω ｃ t) is input.

[0041] The signal wave f input to the modulator 10 ｓ = cos(ω ｓ t) is divided by the dividing unit 107 and input to the phase adjusting unit 108 and the dividing unit 109. The phase adjusting unit 108 divides the input signal wave f ｓ = cos(ω ｓ t) by rotating the phase of the signal wave f ｓ = -sin(ω ｓ t) is converted into a signal wave f ｓ = -sin(ω ｓ t) is divided by the dividing unit 111 and input to each multiplier 120 of the odd-term sideband generating unit 112. For example, if the odd-term sideband generating unit 112 includes three multipliers 120, the dividing unit 111 divides the signal wave f ｓ = -sin(ω ｓ t) to three paths leading to the three multipliers 120. As a result, each multiplier 120 receives a signal wave f ｓ = -sin(ω ｓ t) is input.

[0042] Each multiplier 120 multiplies the input signal wave f ｓ = -sin(ω ｓ t) to a frequency that is a different odd multiple and outputs the frequency to the subsequent multiplier 121. For example, the multiplier 120-1 multiplies the input signal wave f ｓ = -sin(ω ｓ t) is multiplied by 1 to produce a signal wave f ｓ = -sin(ω ｓ For example, the multiplier 120-N multiplies the input signal wave f ｓ = -sin(ω ｓ t) is multiplied by n to produce a signal wave f ｓ = -sin(nω ｓ t) to the subsequent multiplication unit 121-N.

[0043] The multiplication units 121-1 to 121-N multiply the carrier signal f distributed by the distribution unit 106. ｃ =-A ｃ sin(ω ｃ t), the signal wave f output from the multipliers 120-1 to 120-N ｓ = -sin(ω ｓ t) ~ -sin(nω ｓ t), where N is an integer equal to or greater than 1. For example, the multiplier 121-1 multiplies the carrier signal f ｃ =-A ｃ sin(ω ｃ t), the signal wave f output from the multiplier 120-1 ｓ = -sin(ω ｓ The multiplication unit 121-1 multiplies the signal A obtained by the multiplication. ｃ sin(ω ｃ t) sin(ω ｓ t) to the level adjustment unit 122-1. ｃ sin(ω ｃ t) sin(ω ｓ t) can be transformed into the following equation (1) based on the product-sum formula: cos(ω ｃ +ω ｓ )t corresponds to the first upper side wave (+J1), and -cos(ω ｃ -ω ｓ )t corresponds to the first lower side wave (-J1).

[0044]

[0045] Similarly, the multiplication unit 121-N multiplies the carrier signal f distributed by the distribution unit 106 by ｃ =-A ｃ sin(ω ｃ t), the signal wave f output from the multiplier 120-N ｓ = -sin(nω ｓ The multiplication unit 121-N multiplies the signal A obtained by the multiplication. ｃ sin(ω ｃ t) sin(nω ｓ t) to the level adjustment unit 122-N. ｃ sin(ωｃ t) sin(nω ｓ t) can be converted into the following equation (2) based on the product-sum formula: cos(ω ｃ +nω ｓ )t corresponds to the nth upper side wave (+Jn), and -cos(ω ｃ -nω ｓ )t corresponds to the nth lower side wave (-Jn).

[0046]

[0047] Level adjustment units 122-1 to 122-N adjust the amplitude levels of the signals output from multiplication units 121-1 to 121-N and output the adjusted levels. For example, level adjustment unit 122-1 adjusts the amplitude level of the signal output from multiplication unit 121-1 and outputs the adjusted levels. For the sake of simplicity in the description of this configuration, the output of level adjustment unit 122-1 is expressed as [C １ ] may also be expressed as [C １ ] is expressed as the following formula (3). １ represents the amplitude after adjustment.

[0048]

[0049] Similarly, the level adjustment unit 122-N adjusts the amplitude level of the signal output from the multiplication unit 121-N and outputs the adjusted signal. For the sake of simplicity, in this configuration, the output of the level adjustment unit 122-N is expressed as [C ｎ ] may also be expressed as [C ｎ ] is expressed as the following formula (4). ｎ represents the amplitude after adjustment.

[0050]

[0051] Moreover, the signal wave f input to the distribution unit 109 ｓ = cos(ω ｓ t) is distributed by the distributor 109 and input to each multiplier 130 of the even-term sideband generating unit 113. For example, if the even-term sideband generating unit 113 includes three multipliers 130, the distributor 109 divides the signal wave f ｓ = cos(ω ｓt) to three paths leading to the three multipliers 130. As a result, each multiplier 130 receives a signal wave f ｓ = cos(ω ｓ t) is input.

[0052] Each multiplier 130 multiplies the input signal wave f ｓ = cos(ω ｓ t) is multiplied by an even number and output to the subsequent multiplier 131. For example, the multiplier 130-1 multiplies the input signal wave f ｓ = cos(ω ｓ t) to double the frequency of the signal wave f ｓ = cos(2ω ｓ The multiplier 130-M outputs the input signal wave f ｓ = cos(ω ｓ t) is multiplied by m to produce a signal wave f ｓ = cos(mω ｓ t) to the subsequent multiplication unit 131-M, where M is an integer of 1 or greater.

[0053] The multiplication units 131-1 to 131-M multiply the carrier signal f distributed by the distribution unit 110. ｃ = A ｃ cos(ω ｃ t), the signal wave f output from the multipliers 130-1 to 130-M ｓ = cos(2ω ｓ t) ~ cos(mω ｓ For example, the multiplier 131-1 multiplies the carrier signal f ｃ = A ｃ cos(ω ｃ t), the signal wave f output from the multiplier 130-1 ｓ = cos(2ω ｓ The multiplication unit 131-1 multiplies the signal A obtained by the multiplication. ｃ cos(ω ｃ t) cos(2ω ｓ t) to the level adjustment unit 132-1. ｃ cos(ω ｃ t) cos(2ω ｓt) can be transformed into the following equation (5) based on the product-sum formula: cos(ω ｃ +2ω ｓ )t corresponds to the second upper side wave (+J2), and cos(ω ｃ -2ω ｓ )t corresponds to the second lower side wave (-J2).

[0054]

[0055] Similarly, the multiplication unit 131-M multiplies the carrier signal f ｃ = A ｃ cos(ω ｃ t), the signal wave f output from the multiplier 130-M ｓ = cos(mω ｓ The multiplication unit 131-M multiplies the signal A obtained by the multiplication. ｃ cos(ω ｃ t) cos(mω ｓ t) to the level adjustment unit 132-M. ｃ cos(ω ｃ t) cos(mω ｓ t) can be transformed into the following equation (6) based on the product-sum formula: cos(ω ｃ +mω ｓ ) t corresponds to the m-th upper side wave (+Jm), and cos(ω ｃ -mω ｓ )t corresponds to the mth lower side wave (-Jm).

[0056]

[0057] The level adjustment units 132-1 to 132-M adjust the amplitude levels of the signals output from the multiplication units 131-1 to 131-M and output the adjusted levels. For example, the level adjustment unit 132-1 adjusts the amplitude level of the signal output from the multiplication unit 131-1 and outputs the adjusted levels. For the sake of simplicity in the explanation of this configuration, the output of the level adjustment unit 132-1 is expressed as [B ２ ] may also be expressed as [B ２ ] is expressed as the following formula (7). ２ represents the amplitude after adjustment.

[0058]

[0059] Similarly, the level adjustment unit 132-M adjusts the amplitude level of the signal output from the multiplication unit 131-M and outputs the adjusted signal. ｍ ] may also be expressed as [B ｍ ] is expressed as the following formula (8). ｍ represents the amplitude after adjustment.

[0060]

[0061] The modulator 10 converts [A] and [B] obtained by the above processing. ２ ]~[B ｍ ] and [C １ ]~[C ｎ ] are combined by the combining unit 114 to generate a PM signal. That is, the PM signal generated by the modulator 10 is expressed by the following equation (9). Note that the amplitude of each sideband of the PM signal is uniquely determined according to the set modulation index.

[0062]

[0063] The modulator 10 configured as described above can suppress degradation of distortion characteristics. Specifically, the reason the modulator 10 has lower distortion than the conventional system is that, when comparing the frequency spectra of the output signal, the modulator 10 is closer to the ideal frequency spectrum than the conventional system. That is, the modulator 10 can generate more sideband signal waveforms than the conventional system and the Armstrong system. While the Armstrong system has a simple configuration and can be made compact and inexpensive, it can only generate sidebands within the range shown in the box in FIG. 19 (J0, ±J1). Therefore, the Armstrong system differs from the ideal PM signal waveform, which leads to degradation of distortion characteristics and CNR characteristics. In contrast, the modulator 10 not only has the Armstrong system's features of a simple configuration, compactness, and low cost, but can also generate any number of sidebands (J0, ±J1, ±J2, ...). This makes it possible to suppress degradation of distortion characteristics, a problem with the conventional Armstrong system. Furthermore, the CNR characteristics can be improved, which makes it possible to extend the transmission distance and increase the number of modulation levels.

[0064] (Problems with Modulator 10) The modulator 10 shown in FIG. 1 divides the energy of the signal wave input to the modulator 10 equally into each sidewave (J0, ±J1, ±J2, ...) using a divider (e.g., dividers 107, 109, and 111). That is, in the modulator 10, regardless of the sidewave to be generated, the equally divided energy of the signal wave is input to the odd-term sidewave generating unit 112 and the even-term sidewave generating unit 113. As a result, the level adjusting units 122-1 to 122-N and 132-1 to 132-M in the subsequent stages amplify sidewaves with smaller amplitudes than the desired PM spectrum, which can also amplify thermal noise and the like, potentially degrading signal quality. As such, there is room for improvement in the modulator 10 shown in FIG. 1.

[0065] Therefore, in the present invention, a configuration is described in which the amount of energy distribution of the signal wave is devised to eliminate the need for level adjustment units 122-1 to 122-N and level adjustment units 132-1 to 132-M provided in modulator 10, and the SNR (Signal Noise Ratio) of the generated PM waveform is further improved. This will be described in detail below.

[0066] 2 is a configuration diagram of a modulator 10a according to the first embodiment. The modulator 10a includes a carrier signal generating unit 101, a dividing unit 102, a phase adjusting unit 103, a dividing unit 104, a level adjusting unit 105, a dividing unit 106, a dividing unit 110, an odd-term sideband generating unit 112a, an even-term sideband generating unit 113a, a multiplexing unit 114, an information output unit 150, an energy dividing unit 151, N phase adjusting units 152, M phase adjusting units 153, and a phase adjusting unit 154.

[0067] 2, the modulator 10a includes an energy divider 151 before the input signal wave is input to the odd-term sideband generating unit 112a and the even-term sideband generating unit 113a. The modulator 10a uses the energy divider 151 to adjust the amount of energy of the signal wave to be appropriately divided according to the magnitude of each sideband, rather than dividing the energy equally. The magnitude of each sideband of the PM signal (= energy distribution on the frequency axis) differs depending on the modulation index β during PM modulation.

[0068] The information output unit 150 receives information on the modulation index β during PM modulation. The information output unit 150 notifies the energy distribution unit 151 of power information (amplitude information) according to the input modulation index β. Here, the power information includes power information for each sideband and information on the total value of the power of all sidebands. The information output unit 150 holds a power table in which power information according to the modulation index β is registered, and notifies the energy distribution unit 151 of the power information corresponding to the input modulation index β.

[0069] The energy distributor 151 receives the input signal wave and the power information output from the information output unit 150. The energy distributor 151 replicates the input signal wave for the number of output ports. The number of output ports may be any number, but there must be at least as many as the number of sidewaves to be generated. Therefore, when the odd-term sidewave generating unit 112a generates two odd-term sidewaves (e.g., first sidewave (±J1) and third sidewave (±J3)) and the even-term sidewave generating unit 113a generates two even-term sidewaves (e.g., second sidewave (±J2) and fourth sidewave (±J4)), the energy distributor 151 must have at least four output ports.

[0070] When duplicating the signal wave for the number of output ports, the energy distributor 151 distributes the energy at an energy ratio based on the power information output from the information output unit 150. For example, the energy distributor 151 allocates a large amount of energy to a sidewave having a large amplitude (or power obtained by squaring the amplitude), and allocates a small amount of energy to a sidewave having a small amplitude. That is, the energy distributor 151 increases the ratio so that a large amount of energy is allocated to a sidewave component having a large amplitude (or power obtained by squaring the amplitude) of each sidewave component, and decreases the ratio so that a small amount of energy is allocated to a sidewave component having a small amplitude (or power obtained by squaring the amplitude).

[0071] The phase adjustment units 152-1 to 152-N are arranged between the energy distribution unit 151 and the odd-term sideband generation unit 112a. The phase adjustment units 152-1 to 152-N receive the signal waves whose energies have been adjusted by the energy distribution unit 151. The phase adjustment units 152-1 to 152-N adjust the phases of the input signal waves whose energies have been adjusted. For example, the phase adjustment units 152-1 to 152-N rotate the phases of the input signal waves whose energies have been adjusted by 270 degrees or −90 degrees. The signal waves whose phases have been adjusted by the phase adjustment units 152-1 to 152-N are input to the odd-term sideband generation unit 112a.

[0072] Here, phase adjustment units 152-1 to 152-N use phase shifters to rotate the phase of the input signal by 270 degrees or -90 degrees (for example, if the signal wave is cos, it is changed to sin), but any device that can adjust the phase does not have to be a phase shifter, and for example, a delay device may be used, or the wiring path length may be adjusted to change the phase by 270 degrees or -90 degrees.

[0073] The phase adjustment units 153-1 to 153-M are arranged between the energy distribution unit 151 and the even-term sideband generation unit 113a. The phase adjustment units 153-1 to 153-M input signal waves whose energies have been adjusted by the energy distribution unit 151. The phase adjustment units 153-1 to 153-M adjust the phases of the input signal waves whose energies have been adjusted. For example, the phase adjustment units 153-1 to 153-M adjust the phases of the input signal waves whose energies have been adjusted by a predetermined angle (θ ２ , …, θ ｍ The signal waves whose phases have been adjusted by the phase adjusters 153-1 to 153-M are input to the even-term side wave generating unit 113a.

[0074] The phase adjustment unit 154 is disposed between the distribution unit 104 and the level adjustment unit 105. The phase adjustment unit 154 receives the carrier signal distributed by the distribution unit 104. The phase adjustment unit 154 adjusts the phase of the input carrier signal. For example, the phase adjustment unit 154 adjusts the phase of the input carrier signal by a predetermined angle (θ ０ The signal wave whose phase has been adjusted by the phase adjustment unit 154 is input to the level adjustment unit 105.

[0075] The odd-term sidewave generating unit 112a generates odd-term sidewaves. The odd-term sidewave generating unit 112a is composed of one or more multipliers 120 and one or more multipliers 121. As described above, the odd-term sidewave generating unit 112a included in the modulator 10a does not include a level adjusting unit 122. A signal wave whose energy and phase have been adjusted is input to each multiplier 120.

[0076] The even-term sidewave generating unit 113a generates even-term sidewaves. The even-term sidewave generating unit 113a is composed of one or more multipliers 130 and one or more multipliers 131. As described above, the even-term sidewave generating unit 113a included in the modulator 10a does not include a level adjusting unit 132. A signal wave whose energy and phase have been adjusted is input to each multiplier 130.

[0077] FIG. 3 is a diagram for explaining the waveform of an ideal PM signal according to the value of the modulation index β in the first embodiment. The upper part of FIG. 3 shows the waveform of an ideal PM signal when the modulation index β=0.5, the middle part of FIG. 3 shows the waveform of an ideal PM signal when the modulation index β=1, and the lower part of FIG. 3 shows the waveform of an ideal PM signal when the modulation index β=5. Here, "+Jm" in FIG. 3 means the name of the side wave, with "+" meaning that it is at a higher frequency than the carrier wave and "-" meaning that it is at a lower frequency than the carrier wave. Furthermore, "number m" means that it is the mth side wave counting from the carrier wave. "+Jm" can also be read as "the mth upper side wave," and both are synonymous. Furthermore, when expressing the amplitude of "+Jm" in the following description, P Ｊｍ It is written as follows.

[0078] As shown in Figure 3, depending on the modulation index β, the amplitude of each sideband may oscillate rather than decrease monotonically with distance from the carrier (e.g., β = 5). When generating a PM signal for each sideband, it is desirable to distribute the energy of the signal wave according to the magnitude of each sideband. For example, if a low-energy signal wave after multiple branching is used to generate a sideband with a large amplitude, large amplification is required, resulting in degradation of signal quality.

[0079] FIG. 4 is a diagram showing an example of a power table held by the information output unit 150 in the first embodiment. The power table associates input values ​​with output values. In the power table, the input values ​​are values ​​of the modulation index β, and the output values ​​are power information for each sideband and information on the total power value of all sidebands. The information output unit 150 outputs all values ​​registered in the corresponding output value field as power information to the energy distribution unit 151 in accordance with the input value of the modulation index β. The power information for each sideband is calculated in advance for each value of the modulation index β based on the theoretical formula for PM signals. For example, the "information on the total power value of all sidebands" when the modulation index β is 5 stores a value calculated based on Equation (10).

[0080]

[0081] Here, the theoretical formula for a PM signal and amplitude information of the carrier wave and each sidewave calculated in advance for each value of the modulation index β can be obtained, for example, based on the following Reference 1. More specifically, they are described in Equation (1.17) and Figure 1.5 on pages 17 to 19 of Reference 1. Power information (theoretical power information) of the carrier wave and each sidewave can be obtained by squaring the amplitudes of the carrier wave and each sidewave calculated in advance for each value of the modulation index β.

[0082] (Reference 1: Yuya Ito and Akira Fujii, "Easy-to-understand FM Technology", Kosaido Sanpo Publishing, first edition published September 5, 1968, revised fourth edition published June 10, 1978, pp. 17-19.)

[0083] The energy distribution unit 151 replicates the input value f(x) for the number of output ports. The energy (∝f ２ The ratio of (x) is not an equal division, but an energy ratio weighted using a value normalized (divided) by the "power information of each sideband" and the "total value information of the power of all sidebands" output from the information output unit 150. Note that the amount of energy of the input signal and the total amount of energy of the output signal are the same (the amount of energy is conserved between input and output).

[0084] For example, if the number of output ports of the energy distribution unit 151 is two, this means a circuit that generates sidewaves "±J1" and "±J2." If the "power information of each sidewave" output from the information output unit 150 is 5 for "±J1" and 2 for the sidewaves "±J2," and the "total value information of the power of all sidewaves" is 7 (calculated as 5 + 2), the energy distribution unit 151 outputs √(5 / 7) × f(x) to the output port for the sidewaves "±J1," and outputs √(2 / 7) × f(x) to the output port for the sidewaves "±J2."

[0085] Next, the mechanism of the energy distribution unit 151 will be described with reference to FIG. 5. FIG. 5 is a diagram for explaining the mechanism of the energy distribution unit 151 in the first embodiment. The energy distribution unit 151 divides the input signal f(t) at an arbitrary energy ratio and generates a plurality of output signals (f １ (t), f ２ (t), ..., f ｎ＿ｍａｘ 5, when the distribution ratio of the energy distribution unit 151 is 2:1:3, the energy distribution unit 151 distributes the energy as √(2 / 6)×f(t), √(1 / 6)×f(t), and √(3 / 6)×f(t), as shown in the output waveform.

[0086] Since the energy distribution unit 151 only divides the input signal by energy, the energy is conserved between the input and output. ２ １ (t) + f ２ ２ (t) +, ..., +f ２ ｎ＿ｍａｘ (t) = f ２ The energy distribution unit 151 can be realized by a commercially available product, for example, a product called a "splitter" that branches television lines in an apartment building or the like.

[0087] (Operation of Modulator 10a) With the above configuration, the modulator 10a operates as follows. In explaining the operation of the modulator 10a, it is assumed that the carrier signal generated by the carrier signal generating unit 101 is f ｃ = A ｃ cos(ω ｃ t), and the signal wave is f ｓ = cos(ω ｓt).

[0088] The carrier signal generating section 101 of the modulator 10a generates a carrier signal f ｃ = A ｃ cos(ω ｃ t) is output from the carrier signal generating unit 101. ｃ = A ｃ cos(ω ｃ t) is divided by the dividing unit 102 and input to the phase adjusting unit 103 and dividing unit 104. The carrier signal f ｃ = A ｃ cos(ω ｃ t) is divided by the dividing section 104 and input to the phase adjusting section 154 and dividing section 110.

[0089] The phase adjustment unit 154 adjusts the phase of the input carrier signal f ｃ = A ｃ cos(ω ｃ t) to a predetermined angle θ ０ The level adjustment unit 105 adjusts the carrier signal f ｃ = A ｃ cos(ω ｃ t+θ ０ ) is input to the level adjustment unit 105. ｃ = A ｃ cos(ω ｃ t+θ ０ ) and outputs the adjusted amplitude level. ｃ = A ｃ cos(ω ｃ t+θ ０ ) amplitude level is expressed as √(P Ｊ０ / 2P Ａｌｌ ) and output. As a result, the output of level adjustment unit 105 is expressed as in the following equation (11). Note that equation (11) corresponds to the carrier wave (J0). For the sake of simplicity in the explanation of the configuration shown in FIG. 2, the output of level adjustment unit 105 may also be expressed as [A].

[0090]

[0091] The phase adjustment unit 103 adjusts the phase of the input carrier signal f ｃ = A ｃ cos(ω ｃ t) by rotating the phase of the carrier signal f ｃ =-A ｃ sin(ω ｃ t) by the phase adjustment unit 103. ｃ =-A ｃ sin(ω ｃ t) is distributed by the distributor 106 and input to each multiplier 121 of the odd-term sideband generating unit 112. For example, if the odd-term sideband generating unit 112 includes three multipliers 121, the distributor 106 divides the carrier signal f ｃ =-A ｃ sin(ω ｃ t) to three paths leading to the three multipliers 121. As a result, each multiplier 121 receives a carrier signal f ｃ =-A ｃ sin(ω ｃ t) is input.

[0092] The carrier signal f input to the distribution unit 110 ｃ = A ｃ cos(ω ｃ t) is distributed by the distributor 110 and input to each multiplier 131 of the even-term sideband generating unit 113. For example, if the even-term sideband generating unit 113 includes three multipliers 131, the distributor 110 divides the carrier signal f ｃ = A ｃ cos(ω ｃ t) to three paths leading to the three multipliers 131. As a result, each multiplier 131 receives a carrier signal f ｃ = A ｃ cos(ω ｃ t) is input.

[0093] The signal wave f input to the modulator 10 ｓ = cos(ω ｓt) is input to the energy distribution unit 151. The information output unit 150 refers to a power table and acquires power information corresponding to the modulation index β input from the outside. The information output unit 150 outputs the acquired power information to the energy distribution unit 151. The energy distribution unit 151 calculates the power information corresponding to the input signal wave f ｓ = cos(ω ｓ t) is weighted in accordance with the power information output from the information output section 150 and output.

[0094] For example, the energy distributor 151 divides the signal wave f ｓ = cos(ω ｓ t) is weighted based on the power information corresponding to the first sidebands (±J1) and output from the output port to which the multiplier 120-1 of the odd-term sideband generating unit 112a is connected via the phase adjusting unit 152-1. The power information corresponding to the first sidebands (±J1) is P Ｊ１ P, which is indicated by the total power information of all sidebands Ａｌｌ That is, the signal wave f output from the energy distribution unit 151 to the phase adjustment unit 152-1 is expressed as ｓ１ is expressed as the following equation (12).

[0095]

[0096] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = cos(ω ｓ The power information corresponding to the n-th sideband (±Jn) is weighted based on the power information corresponding to the n-th sideband (±Jn) and output from the output port to which the multiplier 120-N of the odd-term sideband generating unit 112a is connected via the phase adjusting unit 152-N. The power information corresponding to the n-th sideband (±Jn) is expressed as P Ｊｎ P, which is indicated by the total power information of all sidebands Ａｌｌ That is, the signal wave f output from the energy distribution unit 151 to the phase adjustment unit 152-N is expressed as ｓｎ is expressed as the following equation (13).

[0097]

[0098] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = cos(ω ｓ The power information corresponding to the second sidebands (±J2) is weighted based on the power information corresponding to the second sidebands (±J2) and output from the output port to which the multiplier 130-1 of the even-term sideband generating unit 113a is connected via the phase adjusting unit 153-1. The power information corresponding to the second sidebands (±J2) is P Ｊ２ P, which is indicated by the total power information of all sidebands Ａｌｌ That is, the signal wave f output from the energy distribution unit 151 to the phase adjustment unit 153-1 is expressed as ｓ２ is expressed as the following equation (14).

[0099]

[0100] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = cos(ω ｓ The power information corresponding to the m-th sideband (±Jm) is weighted based on the power information corresponding to the m-th sideband (±Jm) and output from the output port to which the multiplier 130-M of the even-term sideband generating unit 113a is connected via the phase adjusting unit 153-M. The power information corresponding to the m-th sideband (±Jm) is P Ｊｍ P, which is indicated by the total power information of all sidebands Ａｌｌ That is, the signal wave f output from the energy distribution unit 151 to the phase adjustment unit 153-M is expressed as ｓｍ is expressed as the following equation (15).

[0101]

[0102] The phase adjustment unit 152-1 adjusts the phase of the input signal wave f ｓ１ The phase of the given angle θ １ (For example, θ １ = 270 degrees or -90 degrees). As a result, the signal wave f input to the phase adjustment unit 152-1 is rotated by ｓ１ is converted as shown in the following equation (16). ｓ１ is output to the multiplier 120-1 of the odd-term sideband generating section 112a.

[0103]

[0104] The phase adjustment unit 152-N adjusts the phase of the input signal wave f ｓｎ The phase of the given angle θ ｎ (For example, θ ｎ = 270 degrees or -90 degrees). As a result, the signal wave f input to the phase adjustment unit 152-N is rotated by ｓｎ is converted as shown in the following equation (17). ｓｎ is output to the multiplier 120-N of the odd-term sideband generating section 112a.

[0105]

[0106] The phase adjustment unit 153-1 adjusts the phase of the input signal wave f ｓ２ The phase of the given angle θ ２ As a result, the signal wave f input to the phase adjustment unit 153-1 is rotated by ｓ２ is converted as shown in the following equation (18). ｓ２ is output to the multiplier 130-1 of the even-term sideband generating section 113a.

[0107]

[0108] The phase adjustment unit 153-M adjusts the phase of the input signal wave f ｓｍ The phase of the given angle θ ｍ As a result, the signal wave f input to the phase adjustment unit 153-M is rotated by ｓｍ is converted as shown in the following equation (19). ｓｍ is output to the multiplier 130-M of the even-term sideband generating unit 113a.

[0109]

[0110] The multiplier 120-1 of the odd-term side wave generating unit 112a multiplies the input phase-adjusted signal wave f ｓ１ The multiplier 121-1 multiplies the frequency of the carrier signal f distributed by the distributor 106 by 1 and outputs the multiplied frequency to the multiplier 121-1 at the subsequent stage. ｃ =-A ｃ sin(ωｃ t), the signal wave f output from the multiplier 120-1 ｓ１ The multiplication unit 121-1 outputs the signal obtained by the multiplication to the multiplexing unit 114. For the sake of simplicity, in the configuration shown in FIG. 2, the output of the multiplication unit 121-1 is expressed as [C １ The signal [C １ ] can be transformed into the following formula (20) based on the product-sum formula: ｃ +ω ｓ ) t + θ １} corresponds to the first upper side wave (+J1), and {-cos(ω ｃ -ω ｓ ) t-θ １} corresponds to the first lower side wave (-J1).

[0111]

[0112] The multiplier 120-N of the odd-term sideband generating unit 112a multiplies the input phase-adjusted signal wave f ｓｎ The frequency of the signal wave f is multiplied by n by the multiplier 120-N and output to the subsequent multiplier 121-N. ｓｎ is expressed as the following equation (21).

[0113]

[0114] The multiplication unit 121-N multiplies the carrier signal f distributed by the distribution unit 106 by ｃ =-A ｃ sin(ω ｃ t), the signal wave f output from the multiplier 120-N ｓｎ The multiplication unit 121-N outputs the signal obtained by the multiplication to the multiplexing unit 114. For the sake of simplicity, in the configuration shown in FIG. 2, the output of the multiplication unit 121-N is expressed as [C ｎ The signal [C ｎ ] can be transformed into the following formula (22) based on the product-sum formula: ｃ +nω ｓ ) t + θ ｎ} corresponds to the n-th upper side wave (+Jn), and {-cos(ω ｃ -nω ｓ ) t-θ ｎ} corresponds to the n-th lower side wave (-Jn).

[0115]

[0116] The multiplier 130-1 of the even-term sideband generating unit 113a multiplies the input phase-adjusted signal wave f ｓ２ The frequency of the signal wave f is doubled by the multiplier 130-1 and output to the multiplier 131-1 at the subsequent stage. ｓ２ is expressed as the following equation (23).

[0117]

[0118] The multiplier 131-1 multiplies the carrier signal f distributed by the distributor 110. ｃ = A ｃ cos(ω ｃ t), the signal wave f output from the multiplier 130-1 ｓ２ The multiplication unit 131-1 outputs the signal obtained by the multiplication to the multiplexing unit 114. For the sake of simplicity, in the configuration shown in FIG. 2, the output of the multiplication unit 131-1 is expressed as [B ２ The signal [B ２ ] can be transformed into the following formula (24) based on the product-sum formula: ｃ +2ω ｓ ) t + θ ２} corresponds to the second upper side wave (+J2), and {cos(ω ｃ -2ω ｓ ) t-θ ２} corresponds to the second lower side wave (-J2).

[0119]

[0120] The multiplier 130-M of the even-term sideband generating unit 113a multiplies the input phase-adjusted signal wave f ｓｍ The frequency of the signal wave f is multiplied by m by the multiplier 130-M and output to the subsequent multiplier 131-M. ｓｍ is expressed as the following equation (25).

[0121]

[0122] The multiplication unit 131-M multiplies the carrier signal f distributed by the distribution unit 110. ｃ = A ｃ cos(ω ｃ t), the signal wave f output from the multiplier 130-M ｓｍ The multiplication unit 131-M outputs the signal obtained by the multiplication to the multiplexing unit 114. For the sake of simplicity, in the configuration shown in FIG. 2, the output of the multiplication unit 131-M is expressed as [B ｍ The signal [B ｍ ] can be transformed into the following formula (26) based on the product-sum formula: ｃ +mω ｓ ) t + θ ｍ} corresponds to the m-th upper side wave (+Jm), and {cos(ω ｃ -mω ｓ ) t-θ ｍ} corresponds to the m-th lower side wave (-Jm).

[0123]

[0124] The modulator 10a converts [A] obtained by the above processing and [B] ２ ]~[B ｍ ] and [C １ ]~[C ｎ ] are combined by the combining unit 114 to generate a PM signal. That is, the PM signal generated by the modulator 10a is expressed by the following equation (27). Here, f ＰＭ represents the desired PM waveform (both amplitude, phase, and frequency).

[0125]

[0126] The modulator 10a configured as described above includes an energy divider 151 that divides the signal wave to be transmitted at a predetermined ratio according to the desired level of each sidewave component, an even-term sidewave generating unit 113a that generates one or more signals having even-numbered sidewave components based on the carrier signal and the signal wave divided at the predetermined ratio by the energy divider 151, and an odd-term sidewave generating unit 112a that generates one or more signals having odd-numbered sidewave components based on the carrier signal and the signal wave divided at the predetermined ratio by the energy divider 151.

[0127] As a result, the modulator 10a can improve the SNR of the PM waveform more than the configuration of the modulator 10 shown in FIG. 1 . Specifically, the modulator 10a can eliminate all of the level adjustment units provided in the odd-term sideband generating unit 112 and the even-term sideband generating unit 113 of the modulator 10 shown in FIG. 1 . This simplifies the configuration. Furthermore, since the modulator 10a does not perform correction (amplification) by a level adjustment unit when generating sidebands, it can suppress signal quality degradation caused by amplification of thermal noise. Therefore, it is possible to output a PM waveform with better signal quality (SNR) than the configuration of the modulator 10 shown in FIG. 1 .

[0128] Second Embodiment In the modulator 10a of the first embodiment described above, the energy divider 151 adjusts the energy of the signal wave to an appropriate distribution amount according to the magnitude of each sidewave, eliminating the need for level adjustment when generating even-term and odd-term sidewaves. Here, the modulator 10a is based on the assumption that the amplitude of the signal wave does not change before and after passing through elements such as the phase adjusters 152 and 153 and the multipliers 120 and 130 provided downstream of the energy divider 151. However, in reality, the amplitude of the signal wave may fluctuate when passing through the elements. Therefore, even when the output amplitude of the energy divider 151 is set to an ideal value as in the modulator 10a, amplitude fluctuations may occur due to the influence of passing through each downstream element. In this case, when the signals are combined in the combiner 114 to generate a PM signal, the signal may deviate from the ideal value. As such, there is room for improvement in the modulator 10a shown in FIG. 2 .

[0129] Therefore, in the second embodiment, a configuration will be described that can generate a signal closer to an ideal PM signal even if the amplitude of the signal wave fluctuates due to passing through each element downstream of the energy distribution unit 151. Specifically, in the second embodiment, as an initial adjustment of the modulator, the amplitude of each sideband at the final stage (output side) of the odd-term sideband generating unit 112a and the even-term sideband generating unit 113a is measured, and the measurement results of the amplitude of each sideband are fed back to control the energy distribution ratio in the energy distribution unit 151 so that the amplitude of each sideband approaches the ideal value. This makes it possible to adjust the energy taking into account the amplitude fluctuation when passing through each element. This will be described in detail below.

[0130] 6 is a configuration diagram of a modulator 10b according to the second embodiment. The modulator 10b includes a carrier signal generating unit 101, a dividing unit 102, a phase adjusting unit 103, a dividing unit 104, a level adjusting unit 105, a dividing unit 106, a dividing unit 110, an odd-term sideband generating unit 112b, an even-term sideband generating unit 113b, a multiplexing unit 114, an information output unit 150, an energy dividing unit 151b, N phase adjusting units 152, M phase adjusting units 153, a phase adjusting unit 154, and a control unit 160.

[0131] The modulator 10b differs in configuration from the modulator 10a in that it includes an odd-term sideband generating unit 112b, an even-term sideband generating unit 113b, and an energy dividing unit 151b instead of the odd-term sideband generating unit 112, the even-term sideband generating unit 113, and the energy dividing unit 151, and in that it newly includes a control unit 160. The following description will focus on the differences from the modulator 10a.

[0132] The odd-term sideband generating unit 112b generates odd-term sidebands. The odd-term sideband generating unit 112b is composed of one or more multipliers 120, one or more multipliers 121, and one or more measuring units 123. In this way, the even-term sideband generating unit 113b included in the modulator 10b newly includes measuring units 123-1 to 123-N.

[0133] The measurement units 123-1 to 123-N are arranged after the multiplication units 121-1 to 121-N. The measurement units 123-1 to 123-N measure the amplitude of the signals obtained by the multiplication units 121-1 to 121-N. For example, the measurement unit 123-1 measures the amplitude A of the signal (sidewaves ±J1) obtained by the multiplication unit 121-1. Ｊ１ The measuring unit 123-N measures the amplitude A of the signal (side waves ±Jn) obtained by the multiplier 121-N, for example. Ｊｎ The measuring units 123-1 to 123-N feed back the measurement results to the control unit 160. In this way, the measuring units 123-1 to 123-N feed back information obtained from the waveforms of one or more signals having odd-numbered sideband components (for example, actual measured values ​​of amplitude) to the control unit 160.

[0134] The measuring units 123-1 to 123-N may feed back the waveforms of one or more signals having odd-numbered sideband components to the control unit 160. The measurements by the measuring units 123-1 to 123-N may be performed at least at the timing of the initial adjustment of the modulator 10b.

[0135] The even-term sideband generating unit 113b generates even-term sidebands. The even-term sideband generating unit 113b is composed of one or more multipliers 130, one or more multipliers 131, and one or more measuring units 133. In this way, the even-term sideband generating unit 113b included in the modulator 10b newly includes measuring units 133-1 to 133-M.

[0136] The measurement units 133-1 to 133-M are arranged after the multiplication units 131-1 to 131-M. The measurement units 133-1 to 133-M measure the amplitude of the signals obtained by the multiplication units 131-1 to 131-M. For example, the measurement unit 133-1 measures the amplitude A of the signal (side waves ±J2) obtained by the multiplication unit 131-1. Ｊ２ The measuring unit 133-M measures the amplitude A of the signal (sidewave ±Jm) obtained by the multiplier 131-M, for example. ＪｍThe measuring units 133-1 to 133-M feed back the measurement results to the control unit 160. In this way, the measuring units 133-1 to 133-M feed back information obtained from the waveforms of one or more signals having even-numbered sideband components (for example, actual measured amplitude values) to the control unit 160.

[0137] The measuring units 133-1 to 133-M may feed back the waveforms of one or more signals having even-numbered sideband components to the control unit 160. The measurements by the measuring units 133-1 to 133-M only need to be performed at least at the timing of the initial adjustment of the modulator 10b.

[0138] The control unit 160 controls the energy distribution ratio of the energy distributor 151b based on the measurement results (e.g., the amplitude values ​​of each sideband) fed back from the measurement units 123 and 133. Specifically, the control unit 160 fine-tunes the energy distribution ratio so as to reduce the difference between the theoretical amplitude value of each sideband and the amplitude value of each sideband. Note that when the measurement results fed back from the measurement units 123 and 133 are waveforms of one or more signals having even-numbered sideband components and waveforms of one or more signals having odd-numbered sideband components, the control unit 160 may acquire the amplitude values ​​of each sideband and fine-tune the energy distribution ratio so as to reduce the difference between the theoretical amplitude value of each sideband and the amplitude value of each sideband.

[0139] The operation of the energy distributor 151b is basically the same as that of the energy distributor 151 shown in the first embodiment. When duplicating a signal wave for the number of output ports at the timing of initial adjustment, the energy distributor 151b distributes the energy at an energy ratio based on the power information output from the information output unit 150. Then, after control by the control unit 160 (fine adjustment of the energy distribution ratio) is performed, the energy distributor 151b distributes the signal wave for the number of output ports at the controlled energy distribution ratio.

[0140] (Initial Adjustment Operation of Modulator 10b) Next, the initial adjustment operation performed by the modulator 10b will be described. The initial adjustment operation is an adjustment operation of parameters in the modulator 10b before actual operation (e.g., generating and using a PM signal, etc.) is performed. Fig. 7 is a flowchart showing the processing flow of the initial adjustment operation performed by the modulator 10b in the second embodiment. Note that the explanation of Fig. 7 will be given using the tables shown in Figs. 8 to 10.

[0141] The control unit 160 calculates the output amplitude of the energy distribution unit 151b for each sideband using the method described in the first embodiment (step S101). The method described in the first embodiment is a method based on the power information output from the information output unit 150. Therefore, the output amplitude of the energy distribution unit 151b represents the amplitude obtained for each sideband based on the power information output from the information output unit 150. The control unit 160 generates the table shown in FIG. 8A by storing the value of the output amplitude for each sideband in a table.

[0142] As an example, (A) of Figure 8 shows that the output amplitude of the energy distribution unit 151b corresponding to the first side wave (±J1) is 4, the output amplitude of the energy distribution unit 151b corresponding to the second side wave (±J2) is 3, the output amplitude of the energy distribution unit 151b corresponding to the nth side wave (±Jn) is 1, and the output amplitude of the energy distribution unit 151b corresponding to the mth side wave (±Jm) is 1.

[0143] Next, the control unit 160 calculates the theoretical value of the amplitude of each sideband (step S102). Here, the theoretical value of the amplitude of each sideband is a theoretically derived value of the amplitude of each sideband, such as a value derived based on the aforementioned Reference 1. Alternatively, the theoretical value of the amplitude of each sideband may be derived by numerical simulation of the PM signal. The control unit 160 generates the table shown in FIG. 8B by storing the theoretical value of the amplitude of each sideband in a table in association with the sideband.

[0144] As an example, (B) of Figure 8 shows that the theoretical value of the amplitude of the first side wave (±J1) is 8, the theoretical value of the amplitude of the second side wave (±J2) is 5, the theoretical value of the amplitude of the nth side wave (±Jn) is 2, and the theoretical value of the amplitude of the mth side wave (±Jm) is 1.

[0145] Thereafter, the energy distribution unit 151b in the modulator 10b outputs a signal (step S103). The signal output by the energy distribution unit 151b here is a signal with the output amplitude of each sideband calculated in step S101. As a result, the signal output by the energy distribution unit 151b is input to the phase adjustment units 152-1 to 152-N and the phase adjustment units 153-1 to 153-M. Here, the first sideband will be described as an example, but similar processing is performed for the other sidebands.

[0146] The signal input to phase adjustment unit 152-1 has its phase adjusted, and then multiplied in frequency (for example, by 1) by multiplier 120-1 and output to multiplication unit 121-1. Then, multiplication unit 121-1 multiplies the carrier signal distributed by distribution unit 106 by the signal output from multiplier 120-1. Measurement unit 123-1 measures the amplitude of the signal obtained by multiplication unit 121-1 (step S104). Measurement unit 123-1 feeds back the value of the amplitude of the measured signal to control unit 160.

[0147] This allows the control unit 160 to acquire the actual measurement value for the first sidewave. The control unit 160 acquires the actual measurement values ​​for the other sidewaves (e.g., the second sidewave, ..., the nth sidewave, and the mth sidewave) by performing similar processing. The control unit 160 generates the table shown in FIG. 9A by storing the acquired actual measurement values ​​for each sidewave in a table in association with the sidewave.

[0148] As an example, (A) of Figure 9 shows that the measured value (measured amplitude of the first sidewave) of the first sidewave (±J1) is 5, the measured value (measured amplitude of the first sidewave) of the second sidewave (±J2) is 5.1, the measured value (measured amplitude of the first sidewave) of the nth sidewave (±Jn) is 2.2, and the measured value (measured amplitude of the first sidewave) of the mth sidewave (±Jm) is 1.5.

[0149] The control unit 160 then calculates the difference between the theoretical amplitude value of each sideband and the measured amplitude value of each sideband (step S105). The control unit 160 generates the table shown in FIG. 9B by storing the calculated difference results in a table in association with the sidebands. As an example, FIG. 9B shows that the difference between the theoretical and measured values ​​for the first sideband (±J1) is 3, the difference between the theoretical and measured values ​​for the second sideband (±J2) is 0.1, the difference between the theoretical and measured values ​​for the nth sideband (±Jn) is 0.2, and the difference between the theoretical and measured values ​​for the mth sideband (±Jm) (the measured amplitude of the first sideband) is 0.5.

[0150] The control unit 160 refers to the table shown in FIG. 9B and identifies the sideband with the largest absolute value of the difference (step S106). Referring to the table shown in FIG. 9B, the sideband with the largest absolute value of the difference is the first sideband (±J1). The larger the difference between the theoretical value and the measured value, the larger the fluctuation in amplitude when passing through the element. The control unit 160 determines whether the absolute value of the identified difference satisfies a termination condition (step S107). The termination condition is a condition for terminating the process shown in FIG. 7, and may be, for example, that the ratio between the "absolute value of the identified difference" and the "theoretical value of amplitude" is equal to or less than a predetermined value (e.g., 5%).

[0151] The control unit 160 determines that the termination condition is met when the ratio between the "absolute value of the specified difference" and the "theoretical value of amplitude" is equal to or less than a predetermined value (e.g., 5%). On the other hand, the control unit 160 determines that the termination condition is not met when the ratio between the "absolute value of the specified difference" and the "theoretical value of amplitude" is greater than a predetermined value (e.g., 5%). In the example shown in FIG. 9B, the "absolute value of the specified difference" is 3 and the "theoretical value of amplitude" is 8, resulting in 3 / 8 x 100 = 37.5%. Therefore, the control unit 160 determines that the termination condition is not met.

[0152] If the control unit 160 determines that the termination condition is not satisfied (step S107—NO), the control unit 160 fine-tunes the amplitude values ​​of each output of the energy distributor 151b in a direction that decreases the absolute value of the difference between the identified sidebands (step S108). At this time, the control unit 160 changes the amplitude value of the output corresponding to the sideband with the largest absolute value of the difference by a fixed amount, and fine-tunes the amplitude values ​​of the outputs corresponding to the other sidebands. Note that the fixed amount is assumed to be a preset value.

[0153] To reduce the absolute value of the difference, it is necessary to reduce the difference between the theoretical value and the actual measured value. In the example shown in FIG. 9B, the actual measured value of the first sideband is lower than the theoretical value. To increase the actual measured value of the first sideband, it is necessary to increase the amplitude of the output corresponding to the first sideband in the energy distribution unit 151b. Therefore, if the value of the fixed amount is "1," the control unit 160 increases the amplitude value of each output of the energy distribution unit corresponding to the first sideband (±J1) by "1." Furthermore, the total energy amount must be maintained between the input and output of the energy distribution unit 151b (the total energy amount does not increase or decrease). For example, the sum of the amplitude values ​​of each output of the energy distribution unit 151b must be the same at step S103 and step S107.

[0154] Therefore, the control unit 160 reduces the amplitude values ​​of the outputs of the energy distribution unit 151b corresponding to the other sidewaves by the amount corresponding to the increase of the amplitude value of the outputs of the energy distribution unit 151b corresponding to the first sidewave (±J1) by 1. There are no particular limitations on how much to reduce the amplitude values ​​of the outputs of the energy distribution unit 151b corresponding to the other sidewaves, but possible examples include "reducing by a uniform fixed amount" or "reducing by a uniform fixed rate."

[0155] By executing the process of step S108, the control unit 160 generates a new table shown in FIG. 10 . In the example shown in FIG. 10 , the amplitude value of each output of the energy distributor 151b corresponding to the first sideband (±J1) is increased by “1” and the amplitude values ​​of each output of the energy distributor 151b corresponding to the other sidebands are decreased by “0.25.” The control unit 160 then controls the energy distributor 151b to output the finely adjusted amplitude values ​​of each output of the energy distributor 151b (step S109). Then, the process from step S103 onward is executed. Note that after the control by the control unit 160 is performed in the process of step S109, the energy distributor 151b distributes the energy at an energy distribution ratio that results in the amplitude of each sideband instructed by the control unit 160.

[0156] On the other hand, if the control unit 160 determines that the termination condition is satisfied (step S107—YES), the control unit 160 terminates the processing shown in FIG. 7 . Thereafter, actual operation begins. At this time, the energy distributor 151b of the modulator 10b operates based on the results of the initial adjustment operation. For example, if the control unit 160 controls the energy distributor 151b, the energy distributor 151b distributes energy at an energy distribution ratio that results in the amplitude of each sideband instructed by the control unit 160 even during actual operation. On the other hand, if the control unit 160 does not control the energy distributor 151b, the energy distributor 151b distributes energy at an energy distribution ratio based on the power information obtained from the information output unit 150 during actual operation.

[0157] The modulator 10b configured as described above further includes a control unit 160 that controls the distribution ratio of the energy distributor 151b based on the waveforms of the sidebands obtained from the odd-term sideband generating unit 112b and the even-term sideband generating unit 113b, or information obtained from the waveforms of the sidebands, taking into account the influence of each element (e.g., the phase adjusters 152 and 153 and the multipliers 120 and 130) through which the sideband components passed before generating the signal. The influence of each element refers to amplitude fluctuations and the like resulting from processing by the element. This allows the distribution ratio of the energy distributor 151b to be controlled to reduce the influence of elements such as the phase adjusters 152 and 153 and the multipliers 120 and 130 provided downstream of the energy distributor 151. Therefore, the modulator 10b can control the generated PM signal to approximate an ideal signal. This enables the generation of a more ideal PM signal.

[0158] Furthermore, the control unit 160 controls the distribution ratio of the energy distributor 151b so as to reduce the difference between the waveforms of the sidebands obtained from the odd-term sideband generator 112b and the even-term sideband generator 113b, or between the information obtained from the waveforms of the sidebands and the theoretical values ​​derived from the mathematical expressions. This allows the distribution ratio of the energy distributor 151b to be controlled so as to generate a signal closer to a theoretically derived signal (an ideal signal). This makes it possible to generate a more ideal PM signal.

[0159] (Third Embodiment) In the modulator 10a of the first embodiment described above, the energy divider 151 (first energy divider) adjusts the signal wave energy to an appropriate distribution amount according to the magnitude of each sidewave, eliminating the need for level adjustment when generating even-term sidewaves and odd-term sidewaves. On the other hand, the level adjuster 105 is still provided on the carrier signal side, requiring level adjustment. Because an amplifier is used for level adjustment, signal quality deteriorates due to the influence of thermal noise. To further improve the quality of the PM signal, a configuration that eliminates the need for level adjustment on the carrier signal side is desirable. As such, there is room for improvement in the modulator 10a shown in FIG. 2 .

[0160] Therefore, in the third embodiment, the configuration of the modulator 10a is newly provided with an energy distribution unit for appropriately distributing the energy of the carrier signal at the output of the carrier signal generation unit 101. This makes it possible to generate a signal close to an ideal PM signal even without providing a level adjustment unit 105 on the carrier signal side. This will be described in detail below.

[0161] 11 is a configuration diagram of a modulator 10c according to the third embodiment. The modulator 10c includes a carrier signal generating unit 101, a phase adjusting unit 103, an odd-term sideband generating unit 112a, an even-term sideband generating unit 113a, a multiplexing unit 114, an information output unit 150c, an energy dividing unit 151, N phase adjusting units 152c, M phase adjusting units 153c, a phase adjusting unit 154c, a phase adjusting unit 163, and an energy dividing unit 165.

[0162] Modulator 10c differs in configuration from modulator 10a in that it does not include distribution units 102, 104, 106, and 110, that it includes information output unit 150c, phase adjustment unit 152c, phase adjustment unit 153c, and phase adjustment unit 154c instead of information output unit 150, phase adjustment unit 152, phase adjustment unit 153, and phase adjustment unit 154, and that it newly includes phase adjustment unit 163 and energy distribution unit 165. The following description will focus on the differences from modulator 10a.

[0163] The phase adjustment unit 163 receives a signal wave. The phase adjustment unit 163 adjusts the phase of the input signal wave. For example, the phase adjustment unit 163 rotates the phase of the input signal wave by 270 degrees or −90 degrees. The signal wave whose phase has been adjusted by the phase adjustment unit 163 is input to the energy distribution unit 151.

[0164] Here, the phase adjustment unit 163 uses a phase shifter to rotate the phase of the input signal by 270 degrees or -90 degrees (for example, if the signal wave is cos, it is changed to sin), but it does not have to be a phase shifter as long as it is a device that can adjust the phase; for example, a delay device may be used, or the wiring path length may be adjusted to change the phase by 270 degrees or -90 degrees.

[0165] The phase adjustment units 152c-1 to 152c-N are arranged between the energy distribution unit 151 and the odd-term sideband generation unit 112a. The phase adjustment units 152c-1 to 152c-N input signal waves whose energies have been adjusted by the energy distribution unit 151. The phase adjustment units 152c-1 to 152c-N adjust the phases of the input signal waves whose energies have been adjusted. For example, the phase adjustment units 152c-1 to 152c-N rotate the phases of the input signal waves whose energies have been adjusted by 0 degrees or 360 degrees. The signal waves whose phases have been adjusted by the phase adjustment units 152c-1 to 152c-N are input to the odd-term sideband generation unit 112a.

[0166] Here, the phase adjustment units 152c-1 to 152c-N use phase shifters to rotate the phase of the input signal by 0 degrees or 360 degrees (for example, if the signal wave is cos, it remains cos), but any device capable of adjusting the phase does not have to be a phase shifter, and for example, a delay unit may be used, or the wiring path length may be adjusted to change the phase by 0 degrees or 360 degrees. Also, the modulator 10c does not have to include the phase adjustment units 152c-1 to 152c-N.

[0167] The phase adjustment units 153c-1 to 153c-M are arranged between the energy distribution unit 151 and the even-term sideband generation unit 113a. The phase adjustment units 153c-1 to 153c-M input the signal waves whose energies have been adjusted by the energy distribution unit 151. The phase adjustment units 153c-1 to 153c-M adjust the phases of the input signal waves whose energies have been adjusted. For example, the phase adjustment units 153c-1 to 153c-M rotate the phases of the input signal waves whose energies have been adjusted by 90 degrees. The signal waves whose phases have been adjusted by the phase adjustment units 153c-1 to 153c-M are input to the even-term sideband generation unit 113a.

[0168] Here, the phase adjustment units 153c-1 to 153c-M use phase shifters to rotate the phase of the input signal by 90 degrees (for example, if the signal wave is sine, it is changed to cosine), but any device capable of adjusting the phase does not have to be a phase shifter; for example, a delay device may be used, or the wiring path length may be adjusted to change the phase by 90 degrees.

[0169] The phase adjustment unit 154c is disposed between the energy distribution unit 165 and the multiplexing unit 114. The phase adjustment unit 154c receives the carrier signal whose energy has been adjusted by the energy distribution unit 165. The phase adjustment unit 154c adjusts the phase of the input carrier signal whose energy has been adjusted. For example, the phase adjustment unit 154c rotates the phase of the input carrier signal whose energy has been adjusted by 0 degrees or 360 degrees. The carrier signal whose phase has been adjusted by the phase adjustment unit 154c is input to the multiplexing unit 114.

[0170] Here, a phase shifter is used so that the phase adjustment unit 154c rotates the phase of the input signal by 0 degrees or 360 degrees (for example, if the signal wave is cos, it remains cos), but any device capable of adjusting the phase does not have to be a phase shifter, and for example, a delay unit may be used, or the wiring path length may be adjusted to change the phase by 0 degrees or 360 degrees. Also, the modulator 10c does not need to be equipped with the phase adjustment unit 154c.

[0171] The information output unit 150c receives information on the modulation index β during PM modulation. The information output unit 150c notifies the energy distributor 151 and the energy distributor 165 of power information (amplitude information) according to the input modulation index β. The information output unit 150c holds a power table in which power information according to the modulation index β is registered, and notifies the energy distributor 151 and the energy distributor 165 of the power information corresponding to the input modulation index β.

[0172] In the power table of the third embodiment, output values ​​correspond to input values. In the power table, the input value is the value of modulation index β, and the output values ​​are power information of the carrier wave, power information of each sideband, and information on the total power value of all sidebands. In accordance with the input value of modulation index β, the information output unit 150c outputs all values ​​registered in the corresponding output value field as power information to the energy distribution unit 151 and the energy distribution unit 165. The power information of the carrier wave and the power information of each sideband are calculated in advance for each value of modulation index β based on a theoretical formula for PM signals. The method of determining the distribution ratio in the energy distribution unit 151 and the energy distribution unit 165 will be described later.

[0173] The energy distributor 165 receives the input carrier signal and the power information output from the information output unit 150c. The energy distributor 165 replicates the input carrier signal for the number of output ports. The energy distributor 165 may have any number of output ports, but the number of ports must be at least the same as the number of carrier waves and sidewaves to be generated. Therefore, when the odd-term sidewave generating unit 112a generates two odd-term sidewaves (e.g., first sidewave (±J1) and third sidewave (±J3)) and the even-term sidewave generating unit 113a generates two even-term sidewaves (e.g., second sidewave (±J2) and fourth sidewave (±J4)), the energy distributor 165 must have at least five output ports (four ports for sidewaves and one port for carrier waves).

[0174] When duplicating the carrier signal for the number of output ports, the energy distribution unit 165 distributes the signals at an energy ratio based on the power information output from the information output unit 150c. The energy distribution unit 165 simply divides the input signal by energy, so energy is conserved at the input and output. The energy distribution unit 165 can be realized using a commercially available product, such as a product called a "splitter" that branches television lines in apartment buildings, etc. The energy distribution unit 165 is one aspect of the second energy distribution unit.

[0175] (Operation of Modulator 10c) With the above configuration, the modulator 10c operates as follows. In explaining the operation of the modulator 10c, it is assumed that the carrier signal generated by the carrier signal generating unit 101 is f ｃ = A ｃ cos(ω ｃ t), and the signal wave is f ｓ = cos(ω ｓ t).

[0176] The carrier signal generating section 101 of the modulator 10c generates a carrier signal f ｃ = A ｃ cos(ω ｃ t) is output from the carrier signal generating unit 101. ｃ = A ｃ cos(ω ｃt) is input to the energy distribution unit 165. The information output unit 150c refers to a power table and acquires power information corresponding to the modulation index β input from the outside. The information output unit 150c outputs the acquired power information to the energy distribution units 151 and 165. The energy distribution unit 165 calculates the power information corresponding to the input carrier signal f ｃ = A ｃ cos(ω ｃ t) is weighted in accordance with the power information output from the information output unit 150c and output.

[0177] For example, the energy distributor 165 divides the carrier signal f ｃ = A ｃ cos(ω ｃ The energy distribution unit 165 weights the carrier signal f t based on the power information corresponding to the carrier wave and outputs it from the output port to which the phase adjustment unit 154c is connected. ｃ０ is expressed as the following equation (28).

[0178]

[0179] P in formula (28) ０ represents the amplitude of the carrier wave, and A represents the sum of the amplitudes of all side waves. Here, A is defined as in the following equation (29). This also applies to the following explanation.

[0180]

[0181] In equation (29), K is the number of output ports of the energy distributor 165. That is, K is the number of sidebands to be generated. Therefore, when the PM signals to be generated are J0 to ±J5, K=5.

[0182] Similarly, the energy distributor 165 divides the carrier signal f ｃ = A ｃ cos(ω ｃ The carrier signal f t) is weighted based on the power information corresponding to the first sideband (±J1) and output from the output port connected to the multiplier 121-1 of the odd-term sideband generating unit 112a via the phase adjuster 103. ｃ１is expressed as the following equation (30).

[0183]

[0184] Similarly, the energy distributor 165 divides the carrier signal f ｃ = A ｃ cos(ω ｃ The carrier signal f t) is weighted based on the power information corresponding to the n-th sideband (±Jn) and output from the output port to which the multiplier 121-N of the odd-term sideband generating unit 112a is connected via the phase adjusting unit 103. ｃｎ is expressed as the following equation (31).

[0185]

[0186] Similarly, the energy distributor 165 divides the carrier signal f ｃ = A ｃ cos(ω ｃ The energy distributor 165 weights the carrier signal f t based on the power information corresponding to the second sideband (±J2) and outputs it from the output port to which the multiplier 131-1 of the even-term sideband generator 113a is connected. ｃ２ is expressed as the following equation (32).

[0187]

[0188] Similarly, the energy distributor 165 divides the carrier signal f ｃ = A ｃ cos(ω ｃ The energy distributor 165 weights the carrier signal f t based on the power information corresponding to the m-th sideband (±Jm) and outputs it from the output port to which the multiplier 131-M of the even-term sideband generator 113a is connected. ｃｍ is expressed as the following equation (33).

[0189]

[0190] The phase adjustment unit 154c adjusts the phase of the input carrier signal f ｃ０The phase of the carrier signal f is adjusted by 0 degrees or 360 degrees and output to the multiplexer 114. As a result, the multiplexer 114 receives the carrier signal f ｃ０ In the configuration shown in Fig. 11, for the sake of simplicity, the output of the phase adjustment unit 154c may be represented as [A].

[0191] The phase adjustment unit 103 adjusts the phase of the input carrier signal f ｃ１ (the signal shown in equation (30)) and carrier signal f ｃｎ (the signal shown in equation (31)) are each rotated by 90 degrees to obtain the input carrier signal f ｃ１ is converted into a signal shown in the following equation (34), and a carrier signal f ｃｎ is converted into a signal shown in the following equation (35).

[0192]

[0193]

[0194] The carrier signal f whose phase has been adjusted by the phase adjustment unit 103 ｃ１ (the signal shown in equation (34)) is input to the multiplier 121-1 of the odd-term sideband generating unit 112a. Also, the carrier signal f ｃｎ (the signal shown in equation (35)) is input to the multiplier 121-N of the odd-term sideband generating unit 112a.

[0195] The signal wave f input to the modulator 10c ｓ = cos(ω ｓ t) is input to the phase adjustment unit 163. The phase adjustment unit 163 adjusts the input signal wave f ｓ = cos(ω ｓ t) to a predetermined angle θ １ (For example, θ １ = 270 degrees or -90 degrees). ｓ is the signal wave f ｓ = sin(ω ｓ The phase adjuster 163 converts the phase-adjusted signal wave f ｓ = sin(ω ｓ t) to the energy distribution unit 151.

[0196] The energy distributor 151 divides the signal wave f output from the phase adjuster 163 into ｓ = sin(ω ｓ t) according to the power information output from the information output unit 150. For example, the energy distribution unit 151 weights the signal wave f ｓ = sin(ω ｓ t) is weighted based on the power information corresponding to the first sidebands (±J1) and output from the output port to which the multiplier 120-1 of the odd-term sideband generating unit 112a is connected via the phase adjusting unit 152c-1. The power information corresponding to the first sidebands (±J1) is P Ｊ１ is expressed by dividing the signal wave f ｓ１ is expressed as the following equation (36).

[0197]

[0198] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = sin(ω ｓ The power information corresponding to the n-th sideband (±Jn) is weighted based on the power information corresponding to the n-th sideband (±Jn) and output from the output port to which the multiplier 120-N of the odd-term sideband generating unit 112a is connected via the phase adjusting unit 152c-N. The power information corresponding to the n-th sideband (±Jn) is P Ｊｎ is expressed by dividing the signal wave f ｓｎ is expressed as the following equation (37).

[0199]

[0200] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = sin(ω ｓThe power information corresponding to the second sidebands (±J2) is weighted based on the power information corresponding to the second sidebands (±J2) and output from the output port to which the multiplier 130-1 of the even-term sideband generating unit 113a is connected via the phase adjusting unit 153c-1. The power information corresponding to the second sidebands (±J2) is P Ｊ２ is expressed by dividing the signal wave f ｓ２ is expressed as the following equation (38).

[0201]

[0202] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = sin(ω ｓ The power information corresponding to the m-th sideband (±Jm) is weighted based on the power information corresponding to the m-th sideband (±Jm) and output from the output port to which the multiplier 130-M of the even-term sideband generating unit 113a is connected via the phase adjusting unit 153-M. The power information corresponding to the m-th sideband (±Jm) is P Ｊｍ is expressed by dividing the signal wave f ｓｍ is expressed as the following equation (39).

[0203]

[0204] The phase adjustment unit 152c-1 adjusts the phase of the input signal wave f ｓ１ (the signal shown in equation (36)) is phase-shifted by a predetermined angle θ ２ (For example, θ ２ = 0 degrees or 360 degrees). As a result, the signal wave f input to the phase adjustment unit 152c-1 ｓ１ (the signal shown in equation (36)) is output as is to the multiplier 120-1 of the odd-term side wave generating unit 112a. ｓｎ (the signal shown in equation (37)) by a predetermined angle θ ２ (For example, θ ２= 0 degrees or 360 degrees). As a result, the signal wave f input to the phase adjustment unit 152-N ｓｎ (the signal shown in equation (37)) is output as is to the multiplier 120-N of the odd-term sideband generating section 112a.

[0205] The phase adjustment unit 153c-1 adjusts the phase of the input signal wave f ｓ２ (the signal shown in equation (38)) by a predetermined angle θ １ As a result, the signal wave f input to the phase adjustment unit 153c-1 is rotated by ｓ２ (the signal shown in equation (38)) is converted as shown in the following equation (40). The phase adjustment unit 153c-1 converts the phase-adjusted signal wave f ｓ２ (the signal shown in equation (40)) is output to the multiplier 130-1 of the even-term sideband generating section 113a.

[0206]

[0207] The phase adjustment unit 153c-M adjusts the phase of the input signal wave f ｓｍ (the signal shown in equation (39)) by a predetermined angle θ １ As a result, the signal wave f input to the phase adjustment unit 153c-M is rotated by ｓｍ (the signal shown in equation (39)) is converted as shown in the following equation (41). ｓｍ (the signal shown in equation (41)) is output to the multiplier 130-M of the even-term sideband generating section 113a.

[0208]

[0209] The multiplier 120-1 of the odd-term side wave generating unit 112a multiplies the input phase-adjusted signal wave f ｓ１ The multiplier 121-1 multiplies the frequency of the carrier signal f (the signal shown in equation (36)) by one and outputs it to the multiplier 121-1 at the subsequent stage. ｃ１ (the signal shown in equation (34)), the signal wave f output from the multiplier 120-1 is ｓ１ (the signal shown in equation (36)). The multiplier 121-1 outputs the signal obtained by the multiplication to the multiplexer 114. For the sake of simplicity of explanation in the configuration shown in FIG. 11, the output of the multiplier 121-1 is expressed as [C１ The signal [C １ ] is expressed as the following equation (42).

[0210]

[0211] The multiplier 120-N of the odd-term sideband generating unit 112a multiplies the input phase-adjusted signal wave f ｓｎ The frequency of the signal f (expressed in equation (37)) is multiplied by n and output to the subsequent multiplier 121-N. ｓｎ is expressed as the following equation (43).

[0212]

[0213] The multiplier 121-N multiplies the carrier signal f output from the phase adjuster 103 by ｃｎ (the signal shown in equation (35)), the signal wave f output from the multiplier 120-N is ｓｎ (the signal shown in equation (43)). The multiplier 121-N outputs the signal obtained by the multiplication to the multiplexer 114. For the sake of simplicity of explanation in the configuration shown in FIG. 11, the output of the multiplier 121-N is expressed as [C ｎ The signal [C ｎ ] is expressed as the following equation (44).

[0214]

[0215] The multiplier 130-1 of the even-term sideband generating unit 113a multiplies the input phase-adjusted signal wave f ｓ２ The frequency of the signal f (the signal shown in equation (40)) is doubled and output to the subsequent multiplier 131-1. ｓ２ is expressed as the following equation (45).

[0216]

[0217] The multiplication unit 131-1 multiplies the carrier signal f output from the energy distribution unit 165 by ｃ２ (the signal shown in equation (32)), the signal wave f output from the multiplier 130-1 is ｓ２(the signal shown in equation (45)). The multiplier 131-1 outputs the signal obtained by the multiplication to the multiplexer 114. For the sake of simplicity of explanation in the configuration shown in FIG. 11, the output of the multiplier 131-1 is expressed as [B ２ The signal [B ２ ] is expressed as the following equation (46).

[0218]

[0219] The multiplier 130-M of the even-term sideband generating unit 113a multiplies the input phase-adjusted signal wave f ｓｍ The frequency of the signal f (expressed in equation (41)) is multiplied by m and output to the subsequent multiplier 131-M. ｓｍ is expressed as the following equation (47).

[0220]

[0221] The multiplication unit 131-M multiplies the carrier signal f output from the energy distribution unit 165 by ｃｍ (the signal shown in equation (33)), the signal wave f output from the multiplier 130-M is ｓｍ (the signal shown in equation (47)). The multiplier 131-M outputs the signal obtained by the multiplication to the multiplexer 114. For the sake of simplicity of explanation in the configuration shown in FIG. 11, the output of the multiplier 131-M is expressed as [B ｍ The signal [B ｍ ] is expressed as the following equation (48).

[0222]

[0223] The modulator 10c converts [A] obtained by the above processing and [B] ２ ]~[B ｍ ] and [C １ ]~[C ｎ ] are combined by the combining unit 114 to generate a PM signal. That is, the PM signal generated by the modulator 10c is expressed by the following equation (49). Here, P Ｊ１ , P Ｊ２ , ..., P Ｊｎ, P Ｊｍ represents the ideal amplitude of each sideband.

[0224]

[0225] Using the above-described formulas, a method for determining the distribution ratios in the energy distribution units 151 and 165 will be described. First, the ideal amplitudes (P0, P1, P2, ...) of the carrier wave and each sidewave are derived. Here, the method for deriving the ideal amplitudes of the carrier wave and each sidewave is as described above. For example, the theoretical amplitude values ​​of the carrier wave and each sidewave can be derived by referring to the above-described Reference 1 or by numerical simulation of the PM signal. The theoretical amplitude value of the carrier wave is the theoretically derived value of the amplitude of the carrier wave.

[0226] Next, to determine the output of the energy distributor 165, the derived ideal amplitudes (P0, P1, P2, ...) of the carrier wave and each sidewave are substituted into equations (28), (30), and (31). At the same time, values ​​other than the amplitudes (P0, P1, P2, ...) are also substituted into equations (28), (30), and (31). This makes it possible to determine the output (=distribution ratio) of the energy distributor 165.

[0227] Next, to determine the output of the energy distributor 151, the derived ideal amplitudes (P0, P1, P2, ...) of the carrier wave and each sidewave are substituted into equations (36) and (37). At the same time, values ​​other than the amplitudes (P0, P1, P2, ...) are also substituted into equations (36) and (37). This makes it possible to determine the output (=distribution ratio) of the energy distributor 151.

[0228] The modulator 10c configured as described above includes an energy distributor 165 at the output of the carrier signal generator 101, which distributes the carrier signal at a ratio according to the desired levels of the carrier wave and sideband components. This eliminates the need for a level adjuster on the carrier signal side. Since the modulator 10c thus eliminates the need for level adjustment on the carrier signal side, it is possible to suppress degradation of signal quality due to thermal noise. This allows the modulator 10c to improve the quality of the PM signal it generates.

[0229] (Fourth embodiment) It is also possible to combine the second and third embodiments described above. Therefore, in the fourth embodiment, a configuration combining the second and third embodiments will be described. Note that when the second and third embodiments are combined, the control of the distribution ratio by the control unit is performed not only on the energy distribution unit on the signal wave side but also on the energy distribution unit on the carrier signal side. This will be described in detail below.

[0230] 12 is a configuration diagram of a modulator 10d according to the fourth embodiment. The modulator 10d includes a carrier signal generating unit 101, a phase adjusting unit 103, an odd-term sideband generating unit 112b, an even-term sideband generating unit 113b, a multiplexing unit 114, an information output unit 150c, an energy dividing unit 151b, N phase adjusting units 152c, M phase adjusting units 153c, a phase adjusting unit 154c, a phase adjusting unit 163, an energy dividing unit 165d, and a measuring unit 170.

[0231] The odd-term sideband generating unit 112b, the even-term sideband generating unit 113b, and the energy dividing unit 151b included in the modulator 10d perform the same processing as the functional units with the same names in the second embodiment. The information output unit 150c, the phase adjusting unit 152c, the phase adjusting unit 153c, and the phase adjusting unit 154c included in the modulator 10d perform the same processing as the functional units with the same names in the third embodiment.

[0232] The measurement unit 170 is disposed after the phase adjustment unit 154c. The measurement unit 170 measures the amplitude of the signal after the phase has been adjusted by the phase adjustment unit 154c. The measurement unit 170 feeds back the measurement result to the control unit 160d. In this manner, the measurement unit 170 feeds back information obtained from the waveform of the carrier wave (for example, the measured amplitude value) to the control unit 160d. Note that the measurement unit 170 may also feed back the waveform of the carrier wave to the control unit 160d. Note that the measurement by the measurement unit 170 only needs to be performed at least at the timing of the initial adjustment of the modulator 10d.

[0233] The control unit 160d controls the energy distribution ratios of the energy distributors 151b and 165d based on the measurement results (e.g., the amplitude value of the carrier wave and the amplitude values ​​of each sidewave) fed back from the measurement units 123, 133, and 170. Specifically, the control unit 160d fine-tunes the energy distribution ratios so as to reduce the difference between the theoretical value of the amplitude of the carrier wave and the amplitude value of the carrier wave, and the difference between the theoretical value of the amplitude of each sidewave and the amplitude value of each sidewave.

[0234] In addition, when the measurement results fed back from each measuring unit 123, 133, 170 are the waveform of a carrier wave, the waveforms of one or more signals having even-numbered sidewave components, and the waveforms of one or more signals having odd-numbered sidewave components, the control unit 160d may acquire the amplitude value of the carrier wave and the amplitude value of each sidewave, and fine-tune the energy distribution ratio in the energy distribution unit 151 and the energy distribution unit 165d so that the difference between the theoretical value of the amplitude of the carrier wave and the amplitude value of the carrier wave and the difference between the theoretical value of the amplitude of each sidewave and the amplitude value of each sidewave are small.

[0235] The operation of the energy distribution unit 165d is basically the same as that of the energy distribution unit 165 shown in the third embodiment. When duplicating the carrier signal for the number of output ports at the timing of initial adjustment, the energy distribution unit 165d distributes the energy at an energy ratio based on the power information output from the information output unit 150c. Then, after control by the control unit 160d (fine adjustment of the energy distribution ratio) is performed, the energy distribution unit 165d distributes the carrier signal for the number of output ports at the controlled energy distribution ratio. Because the energy distribution unit 165d simply divides the input signal by energy, energy is conserved at the input and output. The energy distribution unit 165d can be realized using a commercially available product, for example, a product called a "splitter" that branches television lines in apartment buildings, etc.

[0236] (Initial Adjustment Operation of Modulator 10d) Next, the initial adjustment operation performed by the modulator 10d will be described. Fig. 13 is a flowchart showing the processing flow of the initial adjustment operation performed by the modulator 10d in the fourth embodiment. Note that the explanation of Fig. 13 will be given using the tables shown in Figs. 14 to 17.

[0237] The control unit 160d calculates the output amplitudes of the energy distributors 151b and 165d using the method described in the third embodiment (step S201). The method described in the third embodiment is a method based on the power information output from the information output unit 150c. Therefore, the output amplitudes of the energy distributors 151b and 165d represent amplitudes obtained based on the power information output from the information output unit 150c. The control unit 160d generates the table shown in FIG. 14A by storing the values ​​of the output amplitudes of the energy distributors 151b and 165d in a table.

[0238] Here, the energy distributor 151b does not have an output that contributes to the carrier wave (J0). Therefore, the output amplitude of the energy distributor 151b corresponding to the carrier wave (J0) in FIG. 14A is always "-". Note that the signals output from the energy distributor 151b and the energy distributor 165d pass through a phase adjustment unit and a multiplier and ultimately become each side wave (±J1, ±J2, ...). Therefore, in FIGS. 14 to 17, "the signal that ultimately becomes the first side wave (±J1) among the energy distributor output signals" is shown in the ±J1 item.

[0239] 14A shows, as an example, that the output amplitude of the energy distributor 151b corresponding to the first sideband (±J1) is 4, the output amplitude of the energy distributor 151b corresponding to the second sideband (±J2) is 3, the output amplitude of the energy distributor 151b corresponding to the nth sideband (±Jn) is 1, and the output amplitude of the energy distributor 151b corresponding to the mth sideband (±Jm) is 1. Also, FIG. 14A shows, as an example, that the output amplitude of the energy distributor 165d corresponding to the carrier wave (J0) is 7, the output amplitude of the energy distributor 165d corresponding to the first sideband (±J1) is 2, the output amplitude of the energy distributor 165d corresponding to the second sideband (±J2) is 3.5, the output amplitude of the energy distributor 165d corresponding to the nth sideband (±Jn) is 1.2, and the output amplitude of the energy distributor 165d corresponding to the mth sideband (±Jm).

[0240] Next, the control unit 160d calculates the theoretical amplitude values ​​of the carrier wave and each sidewave (step S202). The control unit 160d stores the theoretical amplitude values ​​of the carrier wave and each sidewave in a table in association with each signal, thereby generating the table shown in FIG. 14B.

[0241] As an example, (B) of Figure 14 shows that the theoretical value of the amplitude of the carrier wave (J0) is 10, the theoretical value of the amplitude of the first side wave (±J1) is 8, the theoretical value of the amplitude of the second side wave (±J2) is 5, the theoretical value of the amplitude of the nth side wave (±Jn) is 2, and the theoretical value of the amplitude of the mth side wave (±Jm) is 1.

[0242] Thereafter, the energy distributors 151b and 165d in the modulator 10d output signals (step S203). The signals output by the energy distributors 151b and 165d are signals of the carrier and sideband output amplitudes calculated in step S201. As a result, the signal output by the energy distributor 151b is input to the phase adjusters 152c-1 to 152c-N and the phase adjusters 153c-1 to 153c-M. Furthermore, the signal output by the energy distributor 165d is input to the phase adjusters 103 and 154c and the even-term sideband generating unit 113b. Here, as an example, the first sideband will be described as the even-term sideband, and the second sideband will be described as the odd-term sideband. However, similar processing is performed for the other even-term sidebands and even-term sidebands.

[0243] The measurement unit 170 measures the amplitude of the carrier signal whose energy has been distributed by the energy distribution unit 165d and whose phase has been adjusted by the phase adjustment unit 154c. The measurement unit 170 feeds back the amplitude value of the carrier signal after measurement to the control unit 160d. This allows the control unit 160d to acquire the actual measured value of the carrier wave. The signal input to the phase adjustment unit 152c-1 has its phase adjusted, and then its frequency is multiplied (for example, by 1) by the multiplier 120-1 and output to the multiplication unit 121-1. Then, the multiplication unit 121-1 multiplies the carrier signal whose energy has been distributed by the energy distribution unit 165d and whose phase has been adjusted by the phase adjustment unit 103 by the signal output from the multiplier 120-1. The measurement unit 123-1 measures the amplitude of the signal obtained by the multiplication unit 121-1 (step S204). The measurement unit 123-1 feeds back the amplitude value of the signal after measurement to the control unit 160d.

[0244] This allows the control unit 160d to obtain the actual measured value of the first sideband. Similar processing is performed for the other odd-numbered sidebands (e.g., the third sideband, ..., n-th sideband), allowing the control unit 160d to obtain the actual measured values ​​of the other odd-numbered sidebands. After the phase of the signal input to the phase adjustment unit 153c-1 is adjusted, the frequency is doubled (e.g., 2x) by the multiplier 130-1 and the signal is output to the multiplier 131-1. The multiplier 131-1 then multiplies the carrier signal energy-distributed by the energy distributor 165d by the signal output from the multiplier 130-1. The measurement unit 133-1 measures the amplitude of the signal obtained by the multiplier 131-1 (step S204). The measurement unit 133-1 feeds back the measured signal amplitude value to the control unit 160d. This allows the control unit 160d to obtain the actual measured value of the second sideband. The control unit 160d performs similar processing on the other even-numbered sidebands (e.g., the second sideband, ..., the mth sideband) to obtain actual measured values ​​of the other even-numbered sidebands. The control unit 160d generates the table shown in FIG. 15 by storing the obtained actual measured values ​​of each sideband and carrier wave in a table in association with the signal.

[0245] As an example, Figure 15 shows that the measured value of the carrier wave (J0) (measured amplitude of the carrier wave) is 10.3, the measured value of the first side wave (±J1) (measured amplitude of the first side wave) is 5, the measured value of the second side wave (±J2) (measured amplitude of the first side wave) is 5.1, the measured value of the nth side wave (±Jn) (measured amplitude of the first side wave) is 2.2, and the measured value of the mth side wave (±Jm) (measured amplitude of the first side wave) is 1.5.

[0246] The control unit 160d then calculates the difference between the theoretical amplitude values ​​of the carrier wave and each sidewave and the actual measured amplitude values ​​of the carrier wave and each sidewave (step S205). The control unit 160d generates the table shown in FIG. 16 by storing the calculated difference results in a table in association with the signals. As an example, FIG. 16 shows that the difference between the theoretical and actual measured values ​​of the carrier wave (J0) is 0.3, the difference between the theoretical and actual measured values ​​of the first sidewaves (±J1) is 3, the difference between the theoretical and actual measured values ​​of the second sidewaves (±J2) is 0.1, the difference between the theoretical and actual measured values ​​of the nth sidewave (±Jn) is 0.2, and the difference between the theoretical and actual measured value of the mth sidewave (±Jm) (the measured amplitude of the first sidewave) is 0.5.

[0247] The control unit 160d refers to the table shown in FIG. 16 and identifies the signal (carrier wave or side wave) with the largest absolute value of the difference (step S206). Referring to the table shown in FIG. 16, the side wave with the largest absolute value of the difference is the first side wave (±J1). The control unit 160d determines whether the identified absolute value of the difference satisfies a termination condition (step S207). The termination condition is a condition for terminating the process shown in FIG. 13, and may be, for example, that the ratio between the "identified absolute value of the difference" and the "theoretical value of amplitude" is equal to or less than a predetermined value (e.g., 5%).

[0248] The control unit 160d determines that the termination condition is met when the ratio between the "absolute value of the specified difference" and the "theoretical value of amplitude" is equal to or less than a predetermined value (e.g., 5%). On the other hand, the control unit 160d determines that the termination condition is not met when the ratio between the "absolute value of the specified difference" and the "theoretical value of amplitude" is greater than a predetermined value (e.g., 5%). In the example shown in FIG. 16, the "absolute value of the specified difference" is 3 and the "theoretical value of amplitude" is 8, resulting in 3 / 8 × 100 = 37.5%. Therefore, the control unit 160d determines that the termination condition is not met.

[0249] If the control unit 160d determines that the termination condition is not satisfied (step S207—NO), the control unit 160d fine-tunes the amplitude values ​​of each output of the energy distributor 151b in a direction that decreases the absolute value of the difference between the identified signals (step S208). At this time, the control unit 160d changes the amplitude value of the output corresponding to the signal with the largest absolute value of the difference by a fixed amount, and fine-tunes the amplitude values ​​of the outputs corresponding to the other signals. Note that the fixed amount is assumed to be set in advance.

[0250] To reduce the absolute value of the difference, it is necessary to reduce the difference between the theoretical value and the actual measured value. In the example shown in FIG. 16, the actual measured value of the first sideband is lower than the theoretical value. To increase the actual measured value of the first sideband, it is necessary to increase the amplitude of the outputs corresponding to the first sideband in the energy distributors 151b and 165d. Therefore, if the value of the fixed amount is "1," the control unit 160d increases the amplitude value of each output of the energy distributors 151b and 165d corresponding to the first sideband (±J1) by "1." Furthermore, the total energy must be preserved (i.e., the total energy does not increase or decrease) between the input and output of the energy distributors 151b and 165d. For example, the sum of the amplitude values ​​of each output of the energy distributors 165d must be the same at step S203 and step S207.

[0251] Therefore, the control unit 160d reduces the amplitude values ​​of the outputs of the energy distribution units 151b and 165d corresponding to the carrier wave and the other sidewaves by the amount corresponding to the increase of the amplitude values ​​of the outputs of the energy distribution units 151b and 165d corresponding to the first sidewave (±J1) by "1." There are no particular limitations on how much to reduce the amplitude values ​​of the outputs of the energy distribution units 151b and 165d corresponding to the carrier wave and the other sidewaves, but possible examples include "reducing by a uniform amount" or "reducing by a uniform percentage."

[0252] By executing the process of step S208, the control unit 160d generates a new table shown in FIG. 170. In the example shown in FIG. 17, the amplitude values ​​of the outputs of the energy distributors 151b and 165d corresponding to the first sidebands (±J1) are increased by "1," and the amplitude values ​​of the outputs of the energy distributors 151b and 165d corresponding to the carrier and other sidebands are decreased by "0.25." The control unit 160d then controls the energy distributors 151b and 165d to output the fine-adjusted amplitude values ​​of the outputs of the energy distributors 151b and 165d (step S209). Then, the process of step S103 and subsequent steps is executed. Note that after the control by the control unit 160d is performed by the process of step S209, the energy distributors 151b and 165d distribute the energy at an energy distribution ratio that results in the amplitude of each sideband instructed by the control unit 160d.

[0253] On the other hand, if the control unit 160d determines that the termination condition is satisfied (step S207—YES), the control unit 160d terminates the processing shown in FIG. 13 . Thereafter, actual operation begins. At this time, the energy distributor 151b and the energy distributor 165d of the modulator 10d operate based on the results of the initial adjustment operation. For example, if the control unit 160d controls the energy distributor 151b and the energy distributor 165d, the energy distributor 151b and the energy distributor 165d also distribute energy at an energy distribution ratio that results in the amplitude of the carrier wave and each sideband instructed by the control unit 160d during actual operation. On the other hand, if the control unit 160d does not control the energy distributor 151b and the energy distributor 165d, the energy distributor 151b and the energy distributor 165d distribute energy at an energy distribution ratio based on the power information obtained from the information output unit 150c during actual operation.

[0254] According to the modulator 10d configured as above, it is possible to obtain the same effects as those of the second and third embodiments.

[0255] Furthermore, in the modulator 10d, the control unit 160 also controls the distribution ratio in the energy distribution unit 165. Therefore, it is possible to generate a modulated signal with an even higher SNR than in the second and third embodiments.

[0256] (Modification 1 of the First to Fourth Embodiments) In the above-described embodiment, the signal wave f ｓ The case where there is one wave has been explained, but the signal wave f ｓ In this case, a plurality of signal waves f ｓ The frequency-multiplexed signal is input to the input terminal of the distribution unit 107.

[0257] (Modification 2 of the First to Fourth Embodiments) In the above-described embodiment, the signal wave f ｓ In the description of the embodiment and the formulas, a cosine signal is used as the input. However, the signal waves to which the present invention is applicable are not limited to cosine signals, and the present invention can also be applied to signal waves of any shape other than cosine.

[0258] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0259] The present invention can be applied to an Armstrong modulator that performs phase modulation.

[0260] 10, 10a, 10b, 10c, 10d... modulator, 101... carrier signal generating unit, 102, 104, 106, 107, 109, 110, 111... distribution unit, 103, 108, 163... phase adjustment unit, 105, 122-1 to 122-N, 132-1 to 132-M... level adjustment unit, 112, 112a, 112b... odd-term side wave generating unit, 113, 113a, 113b... even-term side wave generating unit, 114... multiplexing unit, 120, 120-1 to 120-N, 130, 130-1 to 130-M... multiplier, 121, 121-1 to 121-N, 131, 131-1 to 131-M... multiplication unit, 123, 123-1 to 123-N, 133, 133-1 to 133-M... measurement unit, 150, 150c... information output unit, 151, 151b, 165, 165d... energy distribution unit, 152-1 to 152-N, 152c-1 to 152c-N... phase adjustment unit, 153-1 to 153-M, 153c-1 to 153c-M... phase adjustment unit, 154, 154c... phase adjustment unit, 160, 160d... control unit

Claims

1. A modulator comprising: a first energy divider that divides a signal wave to be transmitted at a first ratio corresponding to a desired level for each sideband component; an even-term sideband generation unit that generates one or more signals having even-numbered sideband components based on a carrier signal and the signal wave divided at the first ratio by the first energy divider; and an odd-term sideband generation unit that generates one or more signals having odd-numbered sideband components based on the carrier signal and the signal wave divided at the first ratio by the first energy divider.

2. The modulator according to claim 1, wherein the first energy divider determines the first ratio according to a desired level for each sideband component based on a modulation index during phase modulation.

3. The modulator according to claim 2, further comprising an information output unit that outputs information to the first energy distribution unit by referring to a power table in which power information of each sideband component according to a modulation index during the phase modulation is associated with information on the total value of the power of all sidebands, and the first energy distribution unit determines a distribution ratio for each sideband component based on the information output from the information output unit.

4. A modulator according to any one of claims 1 to 3, wherein the first energy distribution unit increases the ratio so that the energy of a sideband component having a large amplitude value or power value is increased, and decreases the ratio so that the energy of a sideband component having a small amplitude value or power value is decreased.

5. A modulator according to any one of claims 1 to 3, further comprising a control unit that controls the distribution ratio in at least the first energy distribution unit based on the waveforms of the one or more signals obtained from the even term sideband generating unit and the odd term sideband generating unit, or information obtained from the waveforms of the one or more signals, taking into account the influence of each element through which the signals passed before being generated, and wherein the first energy distribution unit changes and distributes the first ratio in accordance with the control of the control unit.

6. The modulator according to claim 5, wherein the control unit controls the distribution ratio in at least the first energy distribution unit so as to reduce a difference between a theoretical value and the waveform of each of the one or more signals notified from the even term sideband generating unit and the odd term sideband generating unit, or information obtained from the waveform of each of the one or more signals.

7. A modulator according to any one of claims 1 to 3, further comprising a second energy distribution unit that distributes the carrier signal at a second ratio according to desired levels for each of the carrier wave and sideband components, wherein the even term sideband generation unit generates the one or more signals having even-numbered sideband components based on the signal wave distributed at the first ratio by the first energy distribution unit and the carrier signal distributed at the second ratio by the second energy distribution unit, and the odd term sideband generation unit generates the one or more signals having odd-numbered sideband components based on the signal wave distributed at the first ratio by the first energy distribution unit and the carrier signal distributed at the second ratio by the second energy distribution unit.

8. The modulator according to claim 7, further comprising a control unit that controls the distribution ratio in at least the first energy distribution unit based on the waveforms of the one or more signals obtained from the even term sideband generating unit and the odd term sideband generating unit, respectively, or on information obtained from the waveforms of the one or more signals, taking into account the influence of each element through which the signals passed before being generated, and wherein the first energy distribution unit and the second energy distribution unit change and distribute the first ratio and the second ratio in accordance with the control of the control unit.

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