Modulator

Abstract

Provided is a modulator comprising: a first energy distributing unit that distributes, at a predetermined ratio corresponding to a first level of each sideband component, a signal wave to be transmitted, which has been subjected to integration or an operation approximately equivalent to integration; an even-term sideband generating unit that generates one or more signals having an even-numbered sideband component, on the basis of a carrier signal and the signal wave distributed at the first ratio by the first energy distributing unit; and an odd-term sideband generating unit that generates one or more signals having an odd-numbered sideband component, on the basis of the carrier signal and the signal wave distributed at the first ratio by the first energy distributing unit.　

Description

Modulator

[0001] This application claims priority to PCT / JP2024 / 24644, 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 frequency modulator, and an integrator 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, an integrator 94, a multiplier 95, and a multiplexer 96. The carrier signal generating unit 91 outputs a carrier signal. The dividing unit 92 divides the carrier signal output by the carrier signal generating unit 91 into two. One of the divided carrier signals is input to a 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 rotation 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 multiplexer 96. When the phase adjusting unit 93 is disposed between the dividing unit 92 and the multiplexer 96, the phase rotation in the phase adjusting unit 93 is minus 90 degrees. The integrator 94 integrates the input carrier signal and outputs the integrated signal wave to the multiplier 95. The multiplier 95 multiplies the phase-rotated carrier signal by the integrated signal wave and outputs the multiplied signal to the combiner 96. The combiner 96 outputs a signal obtained by combining the signal output from the multiplier 95 with the other carrier signal distributed by the distributor 92.

[0004] Ryozo Nagahama, "On the Phase Modulation Method for VHF-FM," Hitachi Hyoronsha, Special Issue No. 3, pp. 71-82. Toshiaki Shimoba et al., "Optical Video Distribution Technology Using FM Batch Conversion Method," Institute of Electronics, Information and Communication Engineers, IEICE Technical Report, vol. 119, no. 323, CS2019-84, pp. 97-101, December 2019.

[0005] In a conventional modulator 90, the output signal from a carrier signal generator 91 is split into two, one of which is phase-rotated by 90 degrees using a phase shifter (phase adjustment unit 93), and then this signal is multiplied by a signal wave in a multiplier (multiplication unit 95).The signal multiplied by the multiplier 95 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 frequency modulation signal waveform has first and subsequent sidewave components (second, third, fourth, etc., in FIG. 19 ), as shown in FIG. 19 . In other words, the absence of a 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: an energy distribution unit that distributes a signal wave to be transmitted, which has been integrated or subjected to an operation approximately equivalent to integration, at a predetermined 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 distributed at the predetermined ratio by the energy distribution unit; 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 distributed at the predetermined ratio by the energy distribution unit.

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

[0010] FIG. 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 FM signal waveform according to the value of the modulation index β in the first embodiment. FIG. 3 is a diagram for explaining 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 the 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 the 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] Before describing the specific configuration of the present invention, one possible configuration for solving the problems of the present invention will be described. Fig. 1 is a configuration diagram of a modulator 10a. The modulator 10a includes a carrier signal generating section 101, a dividing section 102, a phase adjusting section 103, a dividing section 104, a level adjusting section 105, a dividing section 106, a dividing section 107, an integrator 108, a dividing section 109, a dividing section 110, a dividing section 111, an odd-term sideband generating section 112, an even-term sideband generating section 113, a combining section 114, and a phase adjusting section 115.

[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; for example, a delay device may be used, or the wiring path length may be adjusted to change the phase by 90 degrees.

[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 integrator 108 receives a signal wave. The signal wave is a signal to be transmitted. The integrator 108 integrates the received signal wave. The signal wave integrated by the integrator 108 is input to the distributor 107.

[0020] The distributor 107 receives the signal wave integrated by the integrator 108. The distributor 107 distributes the received integrated signal wave. For example, the distributor 107 distributes the received signal wave into two paths. In this case, the distributor 107 distributes the signal wave into a first path and a second path. The distributor 111 is connected to the first path distributed by the distributor 107, and the phase adjuster 115 is connected to the second path distributed by the distributor 107. The integrated signal wave distributed by the distributor 107 is input to the phase adjuster 115 and the distributor 111.

[0021] The divider 111 receives the integrated signal wave distributed by the divider 107. The divider 111 distributes the received integrated signal wave to two or more paths. The integrated signal wave distributed by the divider 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 signal wave distributed by distributor 111 to a different odd multiple (n times) of frequency and outputs the converted signal wave. For example, if three multipliers 120 (N=3) are provided, multiplier 120-1 converts the signal wave distributed by distributor 111 to a frequency of 1x and outputs the converted signal wave, multiplier 120-2 converts the signal wave distributed by distributor 111 to a frequency of 3x and outputs the converted signal wave, and multiplier 120-3 converts the signal wave distributed by distributor 111 to a frequency of 5x and outputs the converted signal wave. In this way, each multiplier 120 converts the signal wave to a frequency of nx and outputs the converted signal wave, where 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 and 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.

[0027] 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.

[0028] The phase adjustment unit 115 is disposed between the distribution unit 107 and the distribution unit 109. The phase adjustment unit 115 receives the integrated signal wave distributed by the distribution unit 107. The phase adjustment unit 115 adjusts the phase of the input integrated signal wave. For example, the phase adjustment unit 115 rotates the phase of the input integrated signal wave by 90 degrees. The signal wave whose phase has been adjusted by the phase adjustment unit 115 is input to the distribution unit 109.

[0029] Here, the phase adjustment unit 115 uses a phase shifter to rotate the phase of the input signal by 90 degrees (for example, changing a signal wave that is sin to cos), 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 90 degrees.

[0030] The dividing unit 109 receives the signal wave whose phase has been adjusted by the phase adjusting unit 115. The dividing unit 109 divides the input signal wave whose phase has been adjusted into two or more paths. The signal wave divided by the dividing unit 109 is input to the even-term sideband generating unit 113.

[0031] 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.

[0032] 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.

[0033] Multiplier 130 converts each signal wave distributed by distributor 109 into a frequency that is a different even multiple (m times) and outputs the converted signal wave. For example, if three multipliers 130 are provided, multiplier 130-1 doubles the frequency of the signal wave distributed by distributor 109 and outputs it, multiplier 130-2 quadruples the frequency of the signal wave distributed by distributor 109 and outputs it, and multiplier 130-3 quadruples the frequency of the signal wave distributed by distributor 109 and outputs it. In this way, each multiplier 130 converts the signal wave into an m-times frequency and outputs it, where m is an even number greater than or equal to 2.

[0034] 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.

[0035] 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.

[0036] 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 .

[0037] The spectrum of a phase-modulated waveform (FM 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 sidewave 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 sidewave.

[0038] (Operation of Modulator) 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 fｓ = cos(ω ｓ t).

[0039] 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 distributed by the distribution unit 104 and input to the level adjustment unit 105 and distribution unit 110.

[0040] 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).

[0041] 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 fｃ =-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.

[0042] 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.

[0043] The signal wave f input to the modulator 10 ｓ = cos(ω ｓ t) is input to the integrator 108. The integrator 108 converts the input signal wave f ｓ = cos(ω ｓ t), the signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ The signal wave f integrated by the integrator 108 is converted into ｓ = (1 / ω ｓ ) sin(ω ｓ t) is divided by dividing section 107 and input to dividing section 111 and phase adjusting section 115.

[0044] The signal wave f input to the distribution unit 111 ｓ = (1 / ω ｓ ) sin(ω ｓt) 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 = (1 / ω 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 = (1 / ω ｓ ) sin(ω ｓ t) is input.

[0045] Each multiplier 120 multiplies the input signal wave f ｓ = (1 / ω 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 = (1 / ω ｓ ) sin(ω ｓ t) is multiplied by 1 to produce a signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ For example, the multiplier 120-N multiplies the input signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ t) is multiplied by n to produce a signal wave f ｓ = (1 / ω ｓ ) sin(nω ｓ t) to the subsequent multiplication unit 121-N.

[0046] 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 = (1 / ω ｓ ) sin(ω ｓ t) ~ (1 / ω ｓ ) 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 = (1 / ω ｓ ) sin(ω ｓ The multiplication unit 121-1 multiplies the signal −(A ｃ / ω ｓ ) sin(ω ｃ t) sin(ω ｓ t) to the level adjustment unit 122-1. ｃ / ω ｓ ) 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).

[0047]

[0048] 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 = (1 / ω ｓ ) sin(nω ｓ The multiplication unit 121-N multiplies the signal −(A ｃ / ω ｓ ) sin(ω ｃ t) sin(nω ｓ t) to the level adjustment unit 122-N. ｃ / ω ｓ ) sin(ω ｃ 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 -nωｓ )t corresponds to the nth lower side wave (-Jn).

[0049]

[0050] 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.

[0051]

[0052] 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.

[0053]

[0054] The phase adjustment unit 115 adjusts the signal wave f divided by the dividing unit 107. ｓ = (1 / ω ｓ ) sin(ω ｓ t) by rotating the phase of the signal wave f ｓ = (1 / ω ｓ ) cos(ω ｓ t) is converted into a signal wave f ｓ = (1 / ω 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 = (1 / ωｓ ) cos(ω ｓ t) to three paths leading to the three multipliers 130. As a result, each multiplier 130 receives a signal wave f ｓ = (1 / ω ｓ ) cos(ω ｓ t) is input.

[0055] Each multiplier 130 multiplies the input signal wave f ｓ = (1 / ω 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 = (1 / ω ｓ ) cos(ω ｓ t) to double the frequency of the signal wave f ｓ = (1 / ω ｓ ) cos(2ω ｓ The multiplier 130-M outputs the input signal wave f ｓ = (1 / ω ｓ ) cos(ω ｓ t) is multiplied by m to produce a signal wave f ｓ = (1 / ω ｓ ) cos(mω ｓ t) to the subsequent multiplication unit 131-M, where M is an integer of 1 or greater.

[0056] 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 = (1 / ω ｓ ) cos(2ω ｓ t) ~ (1 / ω ｓ ) 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 = (1 / ω ｓ ) cos(2ω ｓThe multiplication unit 131-1 multiplies the signal (A ｃ / ω ｓ ) cos(ω ｃ t) cos(2ω ｓ t) to the level adjustment unit 132-1. ｃ / ω ｓ ) cos(ω ｃ t) cos(2ω ｓ t) 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).

[0057]

[0058] 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 = (1 / ω ｓ ) cos(mω ｓ The multiplication unit 131-M multiplies the signal (A ｃ / ω ｓ ) cos(ω ｃ t) cos(mω ｓ t) to the level adjustment unit 132-M. ｃ / ω ｓ ) 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).

[0059]

[0060] 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.

[0061]

[0062] 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. For the sake of simplicity, in this configuration, the output of the level adjustment unit 132-M is expressed as [B ｍ ] may also be expressed as [B ｍ ] is expressed as the following formula (8). ｍ represents the amplitude after adjustment.

[0063]

[0064] The modulator 10a converts [A] obtained by the above processing and [B] ２ ]~[B ｍ ] and [C １ ]~[C ｎ ] are combined by the combiner 114 to generate an FM signal. That is, the FM signal generated by the modulator 10a is expressed by the following equation (9). Note that the amplitude of each sideband of the FM signal is uniquely determined according to the set modulation index.

[0065]

[0066] The modulator 10a configured as described above can suppress degradation of distortion characteristics. Specifically, the reason the modulator 10a has lower distortion than the conventional system is that, when comparing the frequency spectrum of the output signal, the modulator 10a is closer to the ideal frequency spectrum than the conventional system. That is, the modulator 10a can generate more sideband signal waveforms than the conventional Armstrong system. The Armstrong system has a simple configuration, allowing for miniaturization and cost reduction, but 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 FM signal waveform, which leads to degradation of distortion characteristics and CNR characteristics. In contrast, the modulator 10a not only has the Armstrong system's features of simple configuration, miniaturization, and cost reduction, 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.

[0067] (Problems with Modulator 10a) In the modulator 10a shown in FIG. 1, the energy of the signal wave output from the integrator 108 is equally divided into each sidewave (J0, ±J1, ±J2, ...) by a divider (e.g., dividers 107, 109, and 111). That is, in the modulator 10a, 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 FM spectrum, which can also amplify thermal noise and the like, potentially degrading signal quality. As such, there is room for improvement in the modulator 10a shown in FIG. 1.

[0068] Therefore, in the present invention, a configuration is described in which the amount of energy division 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 10a, and the SNR of the generated FM waveform is further improved. This will be explained in detail below.

[0069] 2 is a configuration diagram of a modulator 10b according to the first 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, an integrator 108, 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 151, and M phase adjusting units 152.

[0070] 2, the modulator 10b includes an energy divider 151 before the output from the integrator 108 is input to the odd-term sideband generating unit 112b and the even-term sideband generating unit 113b. The modulator 10b uses the energy divider 151 to adjust the amount of signal wave energy to be distributed appropriately according to the magnitude of each sideband, rather than being equally divided. The magnitude of each sideband of an FM signal (= energy distribution on the frequency axis) differs depending on the modulation index β during FM modulation.

[0071] The information output unit 150 receives information on the modulation index β during FM modulation. The information output unit 150 notifies the energy distribution unit 151 of power 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.

[0072] The energy distributor 151 receives the signal wave integrated by the integrator 108 and the power information output from the information output unit 150 as input. The energy distributor 151 replicates the input integrated 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 112b generates two odd-term sidewaves (e.g., first sidewave (±J1) and third sidewave (±J3)) and the even-term sidewave generating unit 113b 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.

[0073] When duplicating the integrated 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).

[0074] The phase adjustment units 152-1 to 152-M are arranged between the energy distribution unit 151 and the even-term sideband generation unit 113b. The phase adjustment units 152-1 to 152-M receive the signal waves whose energies have been adjusted by the energy distribution unit 151. The phase adjustment units 152-1 to 152-M adjust the phases of the input energy-adjusted signal waves. For example, the phase adjustment units 152-1 to 152-M rotate the phases of the input energy-adjusted signal waves by 90 degrees. The signal waves whose phases have been adjusted by the phase adjustment units 152-1 to 152-M are input to the even-term sideband generation unit 113b.

[0075] Here, phase adjustment units 152-1 to 152-M use phase shifters to rotate the phase of the input signal by 90 degrees (for example, changing a signal wave that is sine to cosine), but any device that can adjust the phase does not need 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.

[0076] The odd-term sidewave generating unit 112b generates odd-term sidewaves. The odd-term sidewave generating unit 112b is composed of one or more multipliers 120 and one or more multipliers 121. As described above, the odd-term sidewave generating unit 112b included in the modulator 10b does not include a level adjusting unit 122. A signal wave whose energy has been adjusted by the energy dividing unit 151 is input to each multiplier 120.

[0077] The even-term sidewave generating unit 113b generates even-term sidewaves. The even-term sidewave generating unit 113b is composed of one or more multipliers 130 and one or more multipliers 131. As such, the even-term sidewave generating unit 113b included in the modulator 10b does not include a level adjusting unit 132. A signal wave whose energy has been adjusted by the energy distributor 151 is input to each multiplier 130.

[0078] FIG. 3 is a diagram for explaining the waveform of an ideal FM 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 FM signal when the modulation index β=0.5, the middle part of FIG. 3 shows the waveform of an ideal FM signal when the modulation index β=1, and the lower part of FIG. 3 shows the waveform of an ideal FM signal when the modulation index β=5. Here, "+Jm" in FIG. 3 means the name of the sidewave, 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 sidewave counting from the carrier wave. "+Jm" can also be read as "the mth upper sidewave," and both are synonymous. Furthermore, when expressing the amplitude of "+Jm" in the following description, P Ｊｍ It is written as follows.

[0079] As shown in Figure 3, depending on the modulation index β, the amplitude of each sideband may not decrease monotonically with distance from the carrier wave but may oscillate (e.g., β = 5). When generating FM signals 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.

[0080] 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 the values ​​of modulation index β, and the output values ​​are power information for each sideband and total power information for all sidebands. Depending on the input value of modulation index β, the information output unit 150 outputs all values ​​registered in the corresponding output value field as power information to the energy distribution unit 151. The power information for each sideband is calculated in advance for each value of modulation index β based on the theoretical formula for FM signals. For example, the "total power information for all sidebands" when modulation index β=5 stores a value calculated based on equation (10).

[0081]

[0082] Here, the theoretical formula for an FM signal and the 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. By squaring the amplitudes of the carrier wave and each sidewave calculated in advance for each value of the modulation index β, the power information (theoretical power information) of the carrier wave and each sidewave can be obtained.

[0083] (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.)

[0084] The energy distribution unit 151 replicates the input value f(x) for the number of output ports. The energy (∝f ２The 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).

[0085] 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."

[0086] 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.

[0087] 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.

[0088] (Operation of Modulator 10b) With the above configuration, the modulator 10b operates as follows. In explaining the operation of the modulator 10b, 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).

[0089] The carrier signal generating section 101 of the modulator 10b 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.

[0090] The level adjustment unit 105 adjusts the input carrier signal f ｃ =A ｃ cos(ω ｃ t) and outputs the carrier signal f ｃ =A ｃ cos(ω ｃ The amplitude level of the signal (P Ｊ０ / 2ω ｓ P 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].

[0091]

[0092] The phase adjustment unit 103 adjusts the phase of the input carrier signal f ｃ =A ｃ cos(ωｃ 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.

[0093] 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.

[0094] The signal wave f input to the modulator 10 ｓ = cos(ω ｓ t) is input to the integrator 108. The integrator 108 converts the input signal wave f ｓ = cos(ω ｓ t), the signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ The signal wave f integrated by the integrator 108 is converted into ｓ= (1 / ω ｓ ) sin(ω ｓ t) is input to the energy distribution unit 151.

[0095] 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 divides the input signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ t) is weighted in accordance with the power information output from the information output section 150 and output.

[0096] For example, the energy distributor 151 divides the signal wave f ｓ = (1 / ω 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 112b is connected. The power information corresponding to the first sidebands (±J1) is calculated by the power information of the first sidebands (±J1) shown in P Ｊ１ P, which is indicated by the total power information of all sidebands Ａｌｌ That is, the signal wave f output by the energy distributor 151 to the multiplier 120-1 of the odd-term sideband generator 112b is expressed as ｓ１ is expressed as the following equation (12).

[0097]

[0098] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ 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 120-N of the odd-term sideband generating unit 112b is connected. 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 ＡｌｌThat is, the signal wave f output by the energy distributor 151 to the multiplier 120-N of the odd-term sideband generator 112b is expressed as ｓｎ is expressed as the following equation (13).

[0099]

[0100] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = (1 / ω ｓ ) sin(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 113b is connected. The power information corresponding to the second sidebands (±J2) is 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 152-1 is expressed as ｓ２ is expressed as the following equation (14).

[0101]

[0102] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = (1 / ω 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 113b is connected. The power information corresponding to the m-th sideband (±Jm) is expressed as 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 152-M is expressed as ｓｍ is expressed as the following equation (15).

[0103]

[0104] The multiplier 120-1 of the odd-term sideband generating unit 112b multiplies the input signal wave f ｓ１The 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(ω ｃ 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 equation (16) 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).

[0105]

[0106] The multiplier 120-N of the odd-term sideband generating unit 112b multiplies the input 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 (17).

[0107]

[0108] 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 equation (18) based on the product-sum formula: cos(ωｃ +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).

[0109]

[0110] The phase adjustment unit 152-1 adjusts the phase of the input signal wave f ｓ２ As a result, the phase of the signal wave f input to the phase adjustment unit 152-1 is rotated by 90 degrees. ｓ２ is converted as shown in the following equation (19). ｓ２ is output to the multiplier 130-1 of the even-term sideband generating section 113b.

[0111]

[0112] The phase adjustment unit 152-M adjusts the phase of the input signal wave f ｓｍ As a result, the phase of the signal wave f input to the phase adjustment unit 152-M is rotated by 90 degrees. ｓｍ is converted as shown in the following equation (20). ｓｍ is output to the multiplier 130-M of the even-term sideband generating unit 113b.

[0113]

[0114] The multiplier 130-1 of the even-term sideband generating unit 113b 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 (21).

[0115]

[0116] The multiplier 130-M of the even-term sideband generating unit 113b 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 (22).

[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 equation (23) 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).

[0119]

[0120] 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 equation (24) 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).

[0121]

[0122] The modulator 10b converts [A] obtained by the above processing and [B] ２ ]~[B ｍ ] and [C １ ]~[C ｎ ] are combined by the combiner 114 to generate an FM signal. That is, the FM signal generated by the modulator 10b is expressed as in the following equation (25). Here, f ＦＭ represents the desired FM waveform (both amplitude, phase and frequency).

[0123]

[0124] The modulator 10b configured as described above includes an energy distributor 151 that distributes the integrated signal wave to be transmitted at a predetermined ratio according to the desired level of each sideband component, an even-term sideband generator 113b that generates one or more signals having even-numbered sideband components based on the carrier signal and the signal wave distributed at the predetermined ratio by the energy distributor 151, and an odd-term sideband generator 112b that generates one or more signals having odd-numbered sideband components based on the carrier signal and the signal wave distributed at the predetermined ratio by the energy distributor 151.

[0125] As a result, the modulator 10b can improve the SNR of the FM waveform more than the configuration of the modulator 10a shown in FIG. 1. Specifically, the modulator 10b 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 10a shown in FIG. 1. This simplifies the configuration. Furthermore, since the modulator 10b 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 an FM waveform with better signal quality (SNR) than the configuration of the modulator 10a shown in FIG. 1.

[0126] Second Embodiment In the modulator 10b 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 10b 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 adjuster 152 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 elements. Therefore, even when the output amplitude of the energy divider 151 is set to an ideal value as in the modulator 10b, amplitude fluctuations may occur due to the influence of each downstream element when the signal wave passes through. In this case, when the signals are combined in the combiner 114 to generate an FM signal, the signal may deviate from the ideal value. As such, there is room for improvement in the modulator 10b shown in FIG. 2.

[0127] Therefore, in the second embodiment, a configuration will be described that can generate a signal closer to an ideal FM 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 in the odd-term sideband generating unit and the final stage (output side) of the even-term sideband generating unit 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.

[0128] 6 is a configuration diagram of a modulator 10c according to the second embodiment. The modulator 10c 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, an integrator 108, a dividing unit 110, an odd-term sideband generating unit 112c, an even-term sideband generating unit 113c, a multiplexing unit 114, an information output unit 150, an energy dividing unit 151c, M phase adjusting units 152, and a control unit 160.

[0129] The modulator 10c differs in configuration from the modulator 10b in that it includes an odd-term sideband generating unit 112c, an even-term sideband generating unit 113c, and an energy dividing unit 151c instead of the odd-term sideband generating unit 112b, the even-term sideband generating unit 113b, 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 10b.

[0130] The odd-term sideband generating unit 112c generates odd-term sidebands. The odd-term sideband generating unit 112c 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 113c included in the modulator 10c newly includes measuring units 123-1 to 123-N.

[0131] 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.

[0132] 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 10c.

[0133] The even-term sideband generating unit 113c generates even-term sidebands. The even-term sideband generating unit 113c 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 113c included in the modulator 10c newly includes measuring units 133-1 to 133-M.

[0134] 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. Ｊｍ The 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.

[0135] The measuring units 133-1 to 133-M may feed back the waveforms of the 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 may be performed at least at the timing of the initial adjustment of the modulator 10c.

[0136] The control unit 160 controls the energy distribution ratio of the energy distributor 151c 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.

[0137] The operation of the energy distributor 151c 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 151c distributes the energy at an energy ratio based on the power information output from the information output unit 150. After control by the control unit 160 (fine adjustment of the energy distribution ratio) is performed, the energy distributor 151c distributes the signal wave for the number of output ports at the controlled energy distribution ratio.

[0138] (Initial Adjustment Operation of Modulator 10c) Next, the initial adjustment operation performed by the modulator 10c will be described. The initial adjustment operation is an adjustment operation of parameters in the modulator 10c before actual operation (for example, generating and using an FM signal, etc.) is performed. Fig. 7 is a flowchart showing the processing flow of the initial adjustment operation performed by the modulator 10c in the second embodiment. Note that the explanation of Fig. 7 will be given using the tables shown in Figs. 8 to 10.

[0139] The control unit 160 calculates the output amplitude of the energy distribution unit 151c 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 151c 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.

[0140] As an example, (A) of Figure 8 shows that the output amplitude of the energy distribution unit 151c corresponding to the first sidewave (±J1) is 4, the output amplitude of the energy distribution unit 151c corresponding to the second sidewave (±J2) is 3, the output amplitude of the energy distribution unit 151c corresponding to the nth sidewave (±Jn) is 1, and the output amplitude of the energy distribution unit 151c corresponding to the mth sidewave (±Jm) is 1.

[0141] Next, the control unit 160 calculates the theoretical amplitude value of each sideband (step S102). Here, the theoretical amplitude value of each sideband refers to a theoretically derived amplitude value of each sideband, such as a value derived based on the aforementioned Reference 1. Alternatively, the theoretical amplitude value of each sideband may be derived by numerical simulation of the FM signal. The control unit 160 generates the table shown in FIG. 8B by storing the theoretical amplitude value of each sideband in a table in association with the sideband.

[0142] 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.

[0143] Thereafter, the energy distributor 151c in the modulator 10c outputs a signal (step S103). The signal output by the energy distributor 151c here is a signal of the output amplitude of each sideband calculated in step S101. As a result, the signals output by the energy distributor 151c are input to the phase adjustment units 152-1 to 152-M. Here, as an example, the first sideband will be described as an even-term sideband, and the second sideband will be described as an odd-term sideband. However, similar processing is performed for the other even-term sidebands and odd-term sidebands.

[0144] The signal output from the energy distributor 151c is frequency-multiplied (for example, by 1) in the multiplier 120-1 and output to the multiplier 121-1. Then, the multiplier 121-1 multiplies the carrier signal distributed by the distributor 106 by the signal output from the multiplier 120-1. The measuring unit 123-1 measures the amplitude of the signal obtained by the multiplier 121-1 (step S104). The measuring unit 123-1 feeds back the value of the amplitude of the signal after the measurement to the control unit 160.

[0145] This allows the control unit 160 to obtain the actual measurement value of the first sideband. Note that similar processing is performed for the other odd-numbered sidebands (e.g., the third sideband, ..., n-th sideband), allowing the control unit 160 to obtain the actual measurement values ​​of the other odd-numbered sidebands.

[0146] The signal input to phase adjustment unit 152-1 has its phase adjusted, and then multiplied by frequency double (for example, by 2) in multiplier 130-1 and output to multiplier 131-1. Then, multiplier 131-1 multiplies the carrier signal distributed by distributor 110 by the signal output from multiplier 130-1. Measurement unit 133-1 measures the amplitude of the signal obtained by multiplier 131-1 (step S104). Measurement unit 133-1 feeds back the measured signal amplitude value to control unit 160.

[0147] This allows the control unit 160 to acquire the actual measurement value of the second sideband. The control unit 160 acquires the actual measurement values ​​of the other even-numbered sidebands (e.g., the second sideband, ..., m-th sideband) by performing similar processing for the other even-numbered sidebands. The control unit 160 generates the table shown in FIG. 9A by storing the acquired actual measurement values ​​of each sideband in a table in association with the sideband.

[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 151c 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 151c. 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 amount of energy must be preserved (i.e., the total amount of energy does not increase or decrease) between the input and output of the energy distribution unit 151c. For example, the sum of the amplitude values ​​of each output of the energy distribution unit 151c 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 151c corresponding to the other sidewaves by the amount corresponding to the increase of the amplitude value of the outputs of the energy distribution unit 151c 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 151c 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 151c corresponding to the first sideband (±J1) is increased by “1” and the amplitude values ​​of each output of the energy distributor 151c corresponding to the other sidebands are decreased by “0.25.” The control unit 160 then controls the energy distributor 151c to output the finely adjusted amplitude values ​​of each output of the energy distributor 151c (step S109). Thereafter, the processes from step S103 onward are executed. Note that after the control by the control unit 160 is performed in the process of step S109, the energy distributor 151c 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 151c of the modulator 10c operates based on the results of the initial adjustment operation. For example, if the control unit 160 controls the energy distributor 151c, the energy distributor 151c 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 151c, the energy distributor 151c 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 10c configured as described above further includes a control unit 160 that controls the distribution ratio of the energy distributor 151c based on the waveforms of the sidebands obtained from the odd-term sideband generating unit 112c and the even-term sideband generating unit 113c, or information obtained from the waveforms of the sidebands, taking into account the influence of each element (e.g., the phase adjuster 152 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 caused by processing by the element. This allows the distribution ratio of the energy distributor 151c to be controlled so as to reduce the influence of elements such as the phase adjuster 152 and the multipliers 120 and 130 provided downstream of the energy distributor 151c when the signal passes through them. Therefore, the modulator 10c can control the generated FM signal to approximate an ideal signal. This makes it possible to generate a more ideal FM signal.

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

[0159] (Third Embodiment) In the modulator 10b of the first embodiment described above, the energy divider 151 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 effects of thermal noise. To further improve the quality of FM signals, 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 10b shown in FIG. 2 .

[0160] Therefore, in the third embodiment, the configuration of the modulator 10b 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 that is close to an ideal FM 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 10d according to the third embodiment. The modulator 10d includes a carrier signal generating unit 101, a phase adjusting unit 103, an integrator 108, an odd-term sideband generating unit 112b, an even-term sideband generating unit 113b, a multiplexing unit 114, an information output unit 150d, an energy dividing unit 151, M phase adjusting units 152d, and an energy dividing unit 165.

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

[0163] The phase adjustment units 152d-1 to 152d-M are arranged between the energy distribution unit 151 and the even-term sideband generation unit 113b. The phase adjustment units 152d-1 to 152d-M input the signal waves whose energies have been adjusted by the energy distribution unit 151. The phase adjustment units 152d-1 to 152d-M adjust the phases of the input signal waves whose energies have been adjusted. For example, the phase adjustment units 152d-1 to 152d-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 152d-1 to 152d-M are input to the even-term sideband generation unit 113b.

[0164] Here, the phase adjustment units 152d-1 to 152d-M use phase shifters to rotate the phase of the input signal by 90 degrees (for example, changing a signal wave that is sine to cosine), but any device that can adjust 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.

[0165] The information output unit 150d receives information on the modulation index β during FM modulation. The information output unit 150d notifies the energy distribution unit 151 and the energy distribution unit 165 of power information (amplitude information) according to the input modulation index β. The information output unit 150d holds a power table in which power information according to the modulation index β is registered, and notifies the energy distribution unit 151 and the energy distribution unit 165 of the power information corresponding to the input modulation index β.

[0166] 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, information output unit 150d outputs all values ​​registered in the corresponding output value item as power information to energy distribution unit 151 and 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 FM signals. The method of determining the distribution ratio in energy distribution unit 151 and energy distribution unit 165 will be described later.

[0167] The energy distributor 165 receives the input carrier signal and the power information output from the information output unit 150d. 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 112b generates two odd-term sidewaves (e.g., the first sidewave (±J1) and the third sidewave (±J3)) and the even-term sidewave generating unit 113b generates two even-term sidewaves (e.g., the second sidewave (±J2) and the fourth sidewave (±J4)), the energy distributor 165 must have at least five output ports (four ports for sidewaves and one port for carrier waves).

[0168] 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 150d. 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.

[0169] (Operation of Modulator 10d) With the above configuration, the modulator 10d operates as follows. In explaining the operation of the modulator 10d, 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).

[0170] The carrier signal generating section 101 of the modulator 10d 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 input to the energy distribution unit 165. The information output unit 150d refers to a power table and acquires power information corresponding to the modulation index β input from outside. The information output unit 150d 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 150d and output.

[0171] 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 connected to the multiplexer 114. ｃ０ is expressed as the following equation (26). As a result, the multiplexer 114 receives the carrier signal f ｃ０ 11, for the sake of simplicity, the output from the energy distribution unit 165 to the multiplexing unit 114 may be expressed as [A]. Note that the ω ｓis the angular frequency of the signal wave. There is no problem if the signal wave has a single angular frequency, but in practice, in many cases the signal wave f ｓ has a bandwidth. Therefore, ω substituted into the output of the energy distribution unit 151 or the energy distribution unit 165 ｓ is not determined to a single value. In this case, one solution is to substitute ω into the output of the energy distribution unit 151 or the energy distribution unit 165. ｓ As the signal wave f ｓ The method of using the center frequency of the signal wave f ｓ It is conceivable to use either the maximum frequency, the minimum frequency, or any predetermined frequency.

[0172]

[0173] P in formula (26) 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 (27). This also applies to the following explanation.

[0174]

[0175] In equation (27), K is the number of output ports of the energy distribution unit 165. That is, K is the number of sidebands to be generated. Therefore, if the FM signals to be generated are J0 to ±J5, K=5.

[0176] 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 112b via the phase adjuster 103. ｃ１ is expressed as the following equation (28).

[0177]

[0178] Similarly, the energy distributor 165 divides the carrier signal f ｃ =A ｃ cos(ω ｃThe 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 112b is connected via the phase adjusting unit 103. ｃｎ is expressed as the following equation (29).

[0179]

[0180] 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 113b is connected. ｃ２ is expressed as the following equation (30).

[0181]

[0182] 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 113b is connected. ｃｍ is expressed as the following equation (31).

[0183]

[0184] The phase adjustment unit 103 adjusts the phase of the input carrier signal f ｃ１ (the signal shown in equation (28)) and carrier signal f ｃｎ (the signal shown in equation (29)) are each rotated by 90 degrees to obtain the input carrier signal f ｃ１ is converted into a signal shown in the following equation (32), and a carrier signal f ｃｎ is converted into a signal shown in the following equation (33).

[0185]

[0186]

[0187] The carrier signal f whose phase has been adjusted by the phase adjustment unit 103 ｃ１ (the signal shown in equation (32)) is input to the multiplier 121-1 of the odd-term sideband generating unit 112b. Also, the carrier signal f ｃｎ (the signal shown in equation (33)) is input to the multiplier 121-N of the odd-term sideband generating unit 112b.

[0188] The signal wave f input to the modulator 10d ｓ = cos(ω ｓ t) is input to the integrator 108. The integrator 108 converts the input signal wave f ｓ = cos(ω ｓ t), the signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ The signal wave f integrated by the integrator 108 is converted into ｓ = (1 / ω ｓ ) sin(ω ｓ t) is input to the energy distribution unit 151.

[0189] The energy distribution unit 151 divides the signal wave f output from the integrator 108 into ｓ = (1 / ω ｓ ) sin(ω ｓ t) according to the power information output from the information output unit 150d. For example, the energy distribution unit 151 weights the signal wave f ｓ = (1 / ω 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 112b is connected. The power information corresponding to the first sidebands (±J1) is calculated by the power information of the first sidebands (±J1) shown in P Ｊ１ is expressed by dividing the signal wave f by A indicated by the total value information of the power of all sidebands. ｓ１is expressed as the following equation (34): ｓ is the angular frequency of the signal wave. There is no problem if the signal wave has a single angular frequency, but in practice, in many cases the signal wave f ｓ has a bandwidth. Therefore, ω ｓ is not determined to a single value. In this case, one solution is to substitute ω into the output of the energy distribution unit 151. ｓ As the signal wave f ｓ The method of using the center frequency of the signal wave f ｓ It is conceivable to use either the maximum frequency, the minimum frequency, or any predetermined frequency.

[0190]

[0191] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ 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 120-N of the odd-term sideband generating unit 112b is connected. The power information corresponding to the n-th sideband (±Jn) is expressed as P Ｊｎ is expressed by dividing the signal wave f by A indicated by the total value information of the power of all sidebands. ｓｎ is expressed as the following equation (35).

[0192]

[0193] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ t) 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 113b is connected via the phase adjusting unit 152d-1. The power information corresponding to the second sidebands (±J2) is P Ｊ２is expressed by dividing the signal wave f ｓ２ is expressed as the following equation (36).

[0194]

[0195] Similarly, the energy distribution unit 151 divides the signal wave f ｓ = (1 / ω 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 113b is connected via the phase adjusting unit 152d-M. The power information corresponding to the m-th sideband (±Jm) is expressed as P Ｊｍ is expressed by dividing the signal wave f ｓｍ is expressed as the following equation (37).

[0196]

[0197] The phase adjustment unit 152d-1 adjusts the phase of the input signal wave f ｓ２ (the signal shown in equation (36)) is phase-shifted by a predetermined angle θ １ As a result, the signal wave f input to the phase adjustment unit 152d-1 is rotated by ｓ２ (the signal shown in equation (36)) is converted as shown in the following equation (38). The phase adjustment unit 152d-1 converts the phase-adjusted signal wave f ｓ２ is output to the multiplier 130-1 of the even-term sideband generating section 113b.

[0198]

[0199] The phase adjustment unit 152d-M adjusts the phase of the input signal wave f ｓｍ (the signal shown in equation (37)) by a predetermined angle θ １ As a result, the signal wave f input to the phase adjustment unit 152d-M is rotated by ｓｍ(the signal shown in equation (37)) is converted as shown in the following equation (39). The phase adjustment unit 152d-M converts the phase-adjusted signal wave f ｓｍ is output to the multiplier 130-M of the even-term sideband generating unit 113b.

[0200]

[0201] The multiplier 120-1 of the odd-term sideband generating unit 112b multiplies the input signal wave f ｓ１ The multiplier 121-1 multiplies the frequency of the carrier signal f (the signal shown in equation (34)) by one and outputs it to the multiplier 121-1 at the subsequent stage. ｃ１ (the signal shown in equation (32)), the signal wave f output from the multiplier 120-1 is ｓ１ (the signal shown in equation (34)). 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 [C １ The signal [C １ ] is expressed as the following equation (40).

[0202]

[0203] The multiplier 120-N of the odd-term sideband generating unit 112b multiplies the input signal wave f ｓｎ The frequency of the signal f (shown in equation (35)) is multiplied by n and output to the subsequent multiplier 121-N. ｓｎ is expressed as the following equation (41).

[0204]

[0205] The multiplier 121-N multiplies the carrier signal f output from the phase adjuster 103 by ｃｎ (the signal shown in equation (33)), the signal wave f output from the multiplier 120-N is ｓｎ (the signal shown in equation (41)). 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 ｎThe signal [C ｎ ] is expressed as the following equation (42).

[0206]

[0207] The multiplier 130-1 of the even-term sideband generating unit 113b multiplies the input phase-adjusted signal wave f ｓ２ The frequency of the signal f (the signal shown in equation (38)) is doubled and output to the subsequent multiplier 131-1. ｓ２ is expressed as the following equation (43).

[0208]

[0209] The multiplication unit 131-1 multiplies the carrier signal f output from the energy distribution unit 165 by ｃ２ (the signal shown in equation (30)), the signal wave f output from the multiplier 130-1 is ｓ２ (the signal shown in equation (43)). 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 (44).

[0210]

[0211] The multiplier 130-M of the even-term sideband generating unit 113b multiplies the input phase-adjusted signal wave f ｓｍ The frequency of the signal f (expressed in equation (39)) is multiplied by m and output to the subsequent multiplier 131-M. ｓｍ is expressed as the following equation (45).

[0212]

[0213] The multiplication unit 131-M multiplies the carrier signal f output from the energy distribution unit 165 by ｃｍ (the signal shown in equation (31)), the signal wave f output from the multiplier 130-M is ｓｍ(the signal shown in equation (45)). 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 (46).

[0214]

[0215] The modulator 10d combines [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 an FM signal. That is, the FM signal generated by the modulator 10d is expressed by the following equation (47). Here, P J１ , P J２ , ..., P Jｎ , P Jｍ represents the ideal amplitude of each sideband.

[0216]

[0217] 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 an FM signal. The theoretical amplitude value of the carrier wave is the theoretically derived value of the amplitude of the carrier wave.

[0218] 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 (26), (28), and (29). At the same time, values ​​other than the amplitudes (P0, P1, P2, ...) are also substituted into equations (26), (28), and (29). This makes it possible to determine the output (=distribution ratio) of the energy distributor 165.

[0219] 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 (34) and (35). At the same time, values ​​other than the amplitudes (P0, P1, P2, ...) are also substituted into equations (34) and (35). This makes it possible to determine the output (=distribution ratio) of the energy distributor 151.

[0220] The modulator 10d 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 sidewave components. This eliminates the need for a level adjuster on the carrier signal side. Since the modulator 10d 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 10d to improve the quality of the FM signal it generates.

[0221] (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.

[0222] 12 is a configuration diagram of a modulator 10e according to the fourth embodiment. The modulator 10e includes a carrier signal generating unit 101, a phase adjusting unit 103, an integrator 108, an odd-term sideband generating unit 112c, an even-term sideband generating unit 113c, a multiplexing unit 114, an information output unit 150d, an energy dividing unit 151c, M phase adjusting units 152d, an energy dividing unit 165e, and a measuring unit 170.

[0223] An odd-term sideband generating unit 112c, an even-term sideband generating unit 113c, and an energy dividing unit 151c included in the modulator 10e perform the same processing as the functional units with the same names in the second embodiment. An information output unit 150d and a phase adjusting unit 152d included in the modulator 10e perform the same processing as the functional units with the same names in the third embodiment.

[0224] The measurement unit 170 is disposed after the energy distribution unit 165e. The measurement unit 170 measures the amplitude of the signal output from the energy distribution unit 165e. The measurement unit 170 feeds back the measurement result to the control unit 160e. In this manner, the measurement unit 170 feeds back information obtained from the waveform of the carrier wave (for example, the actual measured value of the amplitude) to the control unit 160e. Note that the measurement unit 170 may also feed back the waveform of the carrier wave to the control unit 160e. Note that the measurement by the measurement unit 170 only needs to be performed at least at the timing of initial adjustment of the modulator 10e.

[0225] The control unit 160e controls the energy distribution ratios of the energy distribution units 151c and 165e 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 160e fine-tunes the energy distribution ratios of the energy distribution units 151c and 165e 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.

[0226] 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 160e 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 151c and the energy distribution unit 165e 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.

[0227] The operation of the energy distribution unit 165e 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 165e distributes the energy at an energy ratio based on the power information output from the information output unit 150d. Then, after control by the control unit 160e (fine adjustment of the energy distribution ratio) is performed, the energy distribution unit 165e distributes the carrier signal for the number of output ports at the controlled energy distribution ratio. Because the energy distribution unit 165e simply divides the input signal by energy, energy is conserved at the input and output. The energy distribution unit 165e can be realized using a commercially available product, for example, a product called a "splitter" that branches television lines in apartment buildings, etc.

[0228] (Initial Adjustment Operation of Modulator 10e) Next, the initial adjustment operation performed by the modulator 10e will be described. Fig. 13 is a flowchart showing the processing flow of the initial adjustment operation performed by the modulator 10e in the fourth embodiment. Note that the explanation of Fig. 13 will be given using the tables shown in Figs. 14 to 17.

[0229] The control unit 160e calculates the output amplitudes of the energy distributors 151c and 165e 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 150d. Therefore, the output amplitudes of the energy distributors 151c and 165e represent amplitudes obtained based on the power information output from the information output unit 150d. The control unit 160e generates the table shown in FIG. 14A by storing the values ​​of the output amplitudes of the energy distributors 151c and 165e in a table.

[0230] Here, the energy distributor 151c does not have an output that contributes to the carrier wave (J0). Therefore, the output amplitude of the energy distributor 151c corresponding to the carrier wave (J0) in FIG. 14A is always "-". Note that the signals output from the energy distributor 151c and the energy distributor 165e 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.

[0231] 14A shows, as an example, that the output amplitude of the energy distributor 151c corresponding to the first sideband (±J1) is 4, the output amplitude of the energy distributor 151c corresponding to the second sideband (±J2) is 3, the output amplitude of the energy distributor 151c corresponding to the nth sideband (±Jn) is 1, and the output amplitude of the energy distributor 151c corresponding to the mth sideband (±Jm) is 1. Also, FIG. 14A shows, as an example, that the output amplitude of the energy distributor 165e corresponding to the carrier wave (J0) is 7, the output amplitude of the energy distributor 165e corresponding to the first sideband (±J1) is 2, the output amplitude of the energy distributor 165e corresponding to the second sideband (±J2) is 3.5, the output amplitude of the energy distributor 165e corresponding to the nth sideband (±Jn) is 1.2, and the output amplitude of the energy distributor 165e corresponding to the mth sideband (±Jm).

[0232] Next, the control unit 160e calculates the theoretical amplitude values ​​of the carrier wave and each sidewave (step S202). The control unit 160e 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.

[0233] 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.

[0234] Thereafter, the energy distributors 151c and 165e in the modulator 10e output signals (step S203). The signals output by the energy distributors 151c and 165e are signals of the output amplitudes of the carrier wave and each sidewave calculated in step S201. As a result, the signal output by the energy distributor 151c is input to the phase adjusters 152d-1 to 152d-M. Furthermore, the signal output by the energy distributor 165e is input to the phase adjuster 103 and the even-term sidewave generator 113c. Here, as an example, the first sidewave will be described as the even-term sidewave, and the second sidewave will be described as the odd-term sidewave. However, similar processing is performed for the other even-term sidewaves and even-term sidewaves.

[0235] The measurement unit 170 measures the amplitude of the carrier signal whose energy has been distributed by the energy distribution unit 165e. The measurement unit 170 feeds back the amplitude value of the carrier signal after measurement to the control unit 160e. This allows the control unit 160e to acquire the actual measured value of the carrier wave. The signal output by the energy distribution unit 151c is frequency-multiplied (for example, by 1) by the multiplier 120-1 and output to the multiplier 121-1. Then, in the multiplier 121-1, the carrier signal whose energy has been distributed by the energy distribution unit 165e and whose phase has been adjusted by the phase adjustment unit 103 is multiplied by the signal output from the multiplier 120-1. The measurement unit 123-1 measures the amplitude of the signal obtained by the multiplier 121-1 (step S204). The measurement unit 123-1 feeds back the amplitude value of the signal after measurement to the control unit 160e.

[0236] This allows the control unit 160e to obtain the actual measurement value of the first sideband. Note that similar processing is performed for the other odd-numbered sidebands (e.g., the third sideband, ..., n-th sideband), allowing the control unit 160e to obtain the actual measurement values ​​of the other odd-numbered sidebands.

[0237] The signal input to the phase adjustment unit 152d-1 has its phase adjusted, and then the frequency is doubled (for example, doubled) in the multiplier 130-1 and output to the multiplier 131-1. Then, in the multiplier 131-1, the carrier signal whose energy has been distributed by the energy distribution unit 165e is multiplied 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 S104). The measurement unit 133-1 feeds back the value of the amplitude of the signal after measurement to the control unit 160e.

[0238] This allows the control unit 160e to obtain the actual measurement value of the second sideband. The control unit 160e also performs similar processing on the other even-numbered sidebands (e.g., the second sideband, ..., m-th sideband) to obtain the actual measurement values ​​of the other even-numbered sidebands. The control unit 160e generates the table shown in FIG. 15 by storing the obtained actual measurement values ​​of each sideband and carrier in a table in association with the signal.

[0239] 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.

[0240] The control unit 160e 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 160e 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.

[0241] The control unit 160e refers to the table shown in FIG. 16 to identify 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 160e 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%).

[0242] The control unit 160e 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 160e 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 x 100 = 37.5%. Therefore, the control unit 160e determines that the termination condition is not met.

[0243] If the control unit 160e determines that the termination condition is not satisfied (step S207—NO), the control unit 160e fine-tunes the amplitude values ​​of each output of the energy distributor 151c in a direction that decreases the absolute value of the difference between the identified signals (step S208). At this time, the control unit 160e 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.

[0244] 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 151c and 165e. Therefore, if the value of the fixed amount is "1," the control unit 160e increases the amplitude value of each output of the energy distributors 151c and 165e 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 151c and 165e. For example, the sum of the amplitude values ​​of each output of the energy distributors 165e must be the same at step S203 and step S207.

[0245] Therefore, the control unit 160e reduces the amplitude values ​​of the outputs of the energy distribution units 151c and 165e corresponding to the carrier wave and the other sidewaves by the amount of the increase in the amplitude values ​​of the outputs of the energy distribution units 151c and 165e corresponding to the first sidewaves (±J1) by "1." There are no particular limitations on how much to reduce the amplitude values ​​of the outputs of the energy distribution units 151c and 165e corresponding to the carrier wave and the other sidewaves, but possible examples include "reducing by a uniform amount" or "reducing by a uniform percentage."

[0246] By executing the process of step S208, the control unit 160e 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 151c and 165e corresponding to the first sidebands (±J1) are increased by "1," and the amplitude values ​​of the outputs of the energy distributors 151c and 165e corresponding to the carrier and other sidebands are decreased by "0.25." The control unit 160e then controls the energy distributors 151c and 165e to output the fine-adjusted amplitude values ​​of the outputs of the energy distributors 151c and 165e (step S209). Then, the process of step S103 and subsequent steps is executed. Note that after the control by the control unit 160e is performed by the process of step S209, the energy distributors 151c and 165e distribute the energy at an energy distribution ratio that results in the amplitude of each sideband instructed by the control unit 160e.

[0247] On the other hand, if the control unit 160e determines that the termination condition is satisfied (step S207—YES), the control unit 160e terminates the processing shown in FIG. 13 . Thereafter, actual operation begins. At this time, the energy distributor 151c and the energy distributor 165e of the modulator 10e operate based on the results of the initial adjustment operation. For example, if the control unit 160e controls the energy distributor 151c and the energy distributor 165e, the energy distributor 151c and the energy distributor 165e 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 160e during actual operation. On the other hand, if the control unit 160e does not control the energy distributor 151c and the energy distributor 165e, the energy distributor 151c and the energy distributor 165e distribute energy at an energy distribution ratio based on power information obtained from the information output unit 150d during actual operation.

[0248] According to the modulator 10e configured as above, it is possible to obtain the same effects as those of the second and third embodiments.

[0249] Furthermore, in the modulator 10e, the control unit 160e also controls the distribution ratio in the energy distribution unit 165e, so that a modulated signal with an even higher SNR can be generated compared to the second and third embodiments.

[0250] (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 For example, in the embodiment, the frequency-multiplexed signal may be input to the input terminal of the integrator 108.

[0251] (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.

[0252] (Variation 3 in the first to fourth embodiments) The integral processing in each of the above-described embodiments (the integral processing described in the text of the specification and in the figures) may be substituted with other processing such as addition, instead of integration, as long as it can produce approximately equivalent mathematical results.

[0253] 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.

[0254] The present invention can be applied to an Armstrong modulator that performs frequency modulation.

[0255] 10a, 10b, 10c, 10d, 10e... modulator, 101... carrier signal generating unit, 102, 104, 106, 107, 109, 110, 111... distribution unit, 103, 115... phase adjustment unit, 105, 122-1 to 122-N, 132-1 to 132-M... level adjustment unit, 108... integrator, 112b, 112c... odd-term side wave generating unit, 113b, 113c... even-term side wave generating unit, 101..., 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, 170... measurement unit, 150, 150d... information output unit, 151, 151c, 165, 165e... energy distribution unit, 152-1 to 152-M, 152d-1 to 152d-M... phase adjustment unit, 160, 160e... control unit

Claims

1. A modulator comprising: a first energy divider that divides a signal wave to be transmitted, which has been integrated or subjected to an operation approximately equivalent to integration, 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 frequency 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 frequency 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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