Modulator and phase modulator

Abstract

This modulator comprises: an even-term side wave generation unit that generates one or more signals having an even-numbered side wave component on the basis of a carrier signal and a signal wave to be transmitted; an odd-term side wave generation unit that generates one or more signals having an odd-numbered side wave component on the basis of the carrier signal and the signal wave; and a multiplexing unit that multiplexes the carrier signal, the one or more signals having an even-numbered side wave component, and the one or more signals having an odd-numbered side wave component.　

Description

Modulators and Phase Modulators

[0001] The present invention relates to a modulator and a phase modulator.

[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. 2 is a diagram showing an example of the configuration of a modulator 90 of the prior art. The modulator 90 is an example of an Armstrong modulator configured as a phase modulator, and a phase adjustment unit is arranged at the input section of the signal wave.

[0003] The modulator 90 includes a carrier signal generating unit 91, a dividing unit 92, a phase adjusting unit 93, a phase adjusting unit 94, a multiplier 95, and a combiner 96. The carrier signal generating unit 91 outputs a carrier signal. The divider 92 divides the carrier signal output by the carrier signal generating unit 91 into two. One of the divided carrier signals is input to the phase adjusting unit 93. The phase adjusting unit 93 performs a phase rotation of 90 degrees on the input carrier signal and then outputs the phase to the multiplier 95. Here, the phase adjusting unit 93 may be configured to be disposed between the dividing unit 92 and the multiplier 95 as shown in FIG. 2 , or may be disposed between the dividing unit 92, which is the output of the other dividing unit 92, and the combiner 96. When the phase adjusting unit 93 is disposed between the dividing unit 92 and the combiner 96, the phase rotation in the phase adjusting unit 93 is minus 90 degrees. The phase adjustment unit 94 rotates the phase of the input carrier signal by 90 degrees and then outputs the result to the multiplication unit 95. The multiplication unit 95 multiplies the phase-rotated carrier signal by the phase-rotated signal wave, and outputs the multiplied signal to the combination unit 96. The combination unit 96 outputs a signal obtained by combining the signal output from the multiplication unit 95 with the other carrier signal distributed by the distribution unit 92.

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

[0005] In a conventional modulator 90, the output signal from a carrier signal generator 91 is split into two, one of which is phase-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 phase modulation signal waveform has the first and subsequent sidewave components (the second, third, fourth, etc. sidewaves in FIG. 2 ) as shown in FIG. 3 . 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 even-term sidewave generating unit that generates one or more signals having even-numbered sidewave components based on a carrier signal and a signal wave to be transmitted; an odd-term sidewave generating unit that generates one or more signals having odd-numbered sidewave components based on the carrier signal and the signal wave; and a multiplexing unit that multiplexes the carrier signal, the one or more signals having the even-numbered sidewave components, and the one or more signals having the odd-numbered sidewave components.

[0009] One aspect of the present invention includes a first divider that divides a signal wave to be transmitted into two paths, a second divider that divides a carrier signal into two paths, a first phase adjuster that adjusts the phase of the signal wave divided into the first path by the first divider, a second phase adjuster that adjusts the phase of the carrier signal divided into the first path by the second divider, and an even-numbered multiplier that generates one or more signals having even-numbered sideband components by multiplying a signal obtained by even-numbering the signal wave divided into the second path by the first divider and the carrier signal divided into the second path by the second divider. an odd-term sidewave generating unit that generates one or more signals having odd-numbered sidewave components by multiplying the signal wave whose phase has been adjusted by the first phase adjusting unit by an odd number, and the carrier signal whose phase has been adjusted by the second phase adjusting unit; and a combining unit that combines the one or more signals having odd-numbered sidewave components generated by the odd-term sidewave generating unit and the one or more signals having even-numbered sidewave components generated by the even-term sidewave generating unit after level adjustment of each sidewave.

[0010] According to the present invention, it is possible to suppress deterioration of the distortion characteristics of the modulated output signal.

[0011] 1 is a diagram illustrating a configuration of a modulator 10 according to an embodiment; FIG. 2 is a diagram illustrating an example of a configuration of a modulator 90 according to a conventional technique; FIG. 3 is a diagram illustrating an example of a signal waveform of an ideal phase modulation method;

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] 1 is a configuration diagram of a modulator 10 according to an embodiment. The modulator 10 includes a carrier signal generating unit 101, a dividing unit 102, a phase adjusting unit 103, a dividing unit 104, a level adjusting unit 105, a dividing unit 106, a dividing unit 107, a phase adjusting unit 108, a dividing unit 109, a dividing unit 110, a dividing unit 111, an odd-term sideband generating unit 112, an even-term sideband generating unit 113, and a multiplexing unit 114.

[0014] 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 dividing unit 102 is one aspect of the second dividing unit. The carrier signal divided by the dividing unit 102 is input to the phase adjusting unit 103 and the dividing unit 104.

[0015] 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. The phase adjustment unit 103 is one aspect of a second phase adjustment unit.

[0016] Here, the phase adjustment unit 103 uses a phase shifter to rotate the phase of the input signal by 90 degrees (for example, if the carrier signal is cos, it is changed to sin), but it does not have to be a phase shifter as long as it is a device that can adjust the phase, and for example, a delay device may be used, or an implementation in which the phase is changed by 90 degrees by adjusting the wiring path length may be used. This is not limited to the phase adjustment unit 103, but is similar to the phase adjustment unit 108.

[0017] 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.

[0018] The level adjustment unit 105 adjusts the level of the input carrier signal and is realized by, for example, a power amplifier or an attenuator.

[0019] 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 carrier signal into one or more paths. The dividing unit 106 is one aspect of a fourth dividing unit. The carrier signal divided by the dividing unit 106 is input to the odd-term sideband generating unit 112.

[0020] The dividing unit 107 inputs a signal wave. The signal wave is a signal to be transmitted. The dividing unit 107 divides the input signal wave. For example, the dividing unit 107 divides the input signal wave into two. In this case, the dividing unit 107 divides the signal wave into a first path and a second path. The phase adjustment unit 108 is connected to the first path divided by the dividing unit 107, and the dividing unit 109 is connected to the second path divided by the dividing unit 107. The dividing unit 107 is one aspect of the first dividing unit. The signal wave divided by the dividing unit 107 is input to the phase adjustment unit 108 and the dividing unit 109.

[0021] The phase adjustment unit 108 receives the signal wave distributed by the distribution unit 107. The phase adjustment unit 108 adjusts the phase of the input signal wave. For example, the phase adjustment unit 108 rotates the phase of the input signal wave by 90 degrees. The signal wave whose phase has been adjusted by the phase adjustment unit 108 is input to the distribution unit 111. The phase adjustment unit 108 is one aspect of a first phase adjustment unit.

[0022] The dividing unit 109 receives the signal wave divided by the dividing unit 107. The dividing unit 109 divides the input signal wave into two or more paths. The dividing unit 109 is one aspect of a fifth dividing unit. The signal wave divided by the dividing unit 109 is input to the even-term sideband generating unit 113.

[0023] 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 dividing unit 110 is one aspect of a sixth dividing unit. The carrier signal divided by the dividing unit 110 is input to the even-term sideband generating unit 113.

[0024] The dividing unit 111 receives the signal wave whose phase has been adjusted by the phase adjusting unit 108. The dividing unit 111 divides the input signal wave into two or more paths. The dividing unit 111 is one aspect of a third dividing unit. The signal wave divided by the dividing unit 111 is input to the odd-term sideband generating unit 112.

[0025] 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.

[0026] 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.

[0027] The multipliers 120 convert each of the signal waves distributed by the distributor 111 to a different odd multiple (n times) of the frequency and output the converted signal waves. For example, if three multipliers 120 are provided, the multiplier 120-1 converts the signal waves distributed by the distributor 111 to a frequency of 1 times the frequency and outputs the converted signal waves, the multiplier 120-2 converts the signal waves distributed by the distributor 111 to a frequency of 3 times the frequency and outputs the converted signal waves, and the multiplier 120-3 converts the signal waves distributed by the distributor 111 to a frequency of 5 times the frequency and outputs the converted signal waves. Here, n is an odd number equal to or greater than 1. The multipliers 120 are one aspect of a second multiplier.

[0028] The multiplier 121 multiplies the signal wave having an odd-multiple 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. The multiplier 121 is one aspect of a second multiplier.

[0029] The level adjustment unit 122 adjusts the level of the input signal. The level adjustment unit 122 is realized by, for example, a power amplifier (amplifier) ​​or an attenuator (attenuator), etc. The level adjustment unit 122 is one aspect of a second level adjustment unit.

[0030] 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.

[0031] 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.

[0032] Multiplier 130 converts each of the signal waves distributed by distributor 109 into a frequency that is a different even multiple (m times) and outputs the converted signal waves. For example, if three multipliers 130 are provided, multiplier 130-1 converts the signal waves distributed by distributor 109 into a frequency that is twice as high and outputs the converted signal waves, multiplier 130-2 converts the signal waves distributed by distributor 109 into a frequency that is four times as high and outputs the converted signal waves, and multiplier 130-3 converts the signal waves distributed by distributor 109 into a frequency that is six times as high and outputs the converted signal waves. Here, m is an even number greater than or equal to 2. Multiplier 130 is one aspect of a first multiplier.

[0033] The multiplier 131 multiplies the signal having an even multiple of 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. The multiplier 131 is one aspect of a first multiplier.

[0034] The level adjustment unit 132 adjusts the level of the input signal. The level adjustment unit 132 is realized by, for example, a power amplifier (amplifier) ​​or an attenuator (attenuator), etc. The level adjustment unit 132 is one aspect of a first level adjustment unit.

[0035] The multiplexer 114 combines the signal [A] output from the level adjuster 105 and the signal [C] output from the odd-term sideband generator 112. １ ]~[C ｎ ] and the signal [B ２ ]~[B ｍ ] and are combined.

[0036] The spectrum of a phase-modulated waveform (PM waveform) (such as the waveform shown in FIG. 3 ) is uniquely determined once parameters such as the modulation index are determined, and the amplitude of each sideband is also uniquely determined. Therefore, as an example of a level adjustment method in each of the level adjustment units 105, 122, and 132 in the above-described embodiment, each of the level adjustment units 105, 122, and 132 may perform level adjustment so that the amplitude component of each sideband has the same value as the ideal amplitude component of each sideband.

[0037] (Operation of Modulator) With the above configuration, the modulator 10 operates as follows. In explaining the operation of the modulator 10, it is assumed that the carrier signal generated by the carrier signal generating unit 101 is f ｃ =A ｃ cos(ω ｃ t), and the signal wave is f ｓ = cos(ω ｓ t).

[0038] The carrier signal generating section 101 of the modulator 10 generates a carrier signal f ｃ =A ｃ cos(ω ｃ t) is output from the carrier signal generating unit 101. ｃ =A ｃ cos(ω ｃ t) is divided by the dividing unit 102 and input to the phase adjusting unit 103 and dividing unit 104. The carrier signal f ｃ =A ｃ cos(ω ｃt) is distributed by the distribution unit 104 and input to the level adjustment unit 105 and distribution unit 110.

[0039] The level adjustment unit 105 adjusts the input carrier signal f ｃ =A ｃ cos(ω ｃ t) and outputs the signal. 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.

[0040] The phase adjustment unit 103 adjusts the phase of the input carrier signal f ｃ =A ｃ cos(ω ｃ t) by rotating the phase of the carrier signal f ｃ =-A ｃ sin(ω ｃ t) by the phase adjustment unit 103. ｃ =-A ｃ sin(ω ｃ t) is distributed by the distributor 106 and input to each multiplier 121 of the odd-term sideband generating unit 112. For example, if the odd-term sideband generating unit 112 includes three multipliers 121, the distributor 106 divides the carrier signal f ｃ =-A ｃ sin(ω ｃ t) to three paths leading to the three multipliers 121. As a result, each multiplier 121 receives a carrier signal f ｃ =-A ｃ sin(ω ｃ t) is input.

[0041] 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 one or more multipliers 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(ωｃ 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.

[0042] The signal wave f input to the modulator 10 ｓ = cos(ω ｓ t) is divided by the dividing unit 107 and input to the phase adjusting unit 108 and the dividing unit 109. The phase adjusting unit 108 divides the input signal wave f ｓ = cos(ω ｓ t) by rotating the phase of the signal wave f ｓ = -sin(ω ｓ t) is converted into a signal wave f ｓ = -sin(ω ｓ t) is divided by the dividing unit 111 and input to each multiplier 120 of the odd-term sideband generating unit 112. For example, if the odd-term sideband generating unit 112 includes three multipliers 120, the dividing unit 111 divides the signal wave f ｓ = -sin(ω ｓ t) to three paths leading to the three multipliers 120. As a result, each multiplier 120 receives a signal wave f ｓ = -sin(ω ｓ t) is input.

[0043] Each multiplier 120 multiplies the input signal wave f ｓ = -sin(ω ｓ t) is converted into a frequency that is a different odd multiple and output to the subsequent multiplier 121. For example, the signal wave f ｓ = -sin(ω ｓ t) is the signal wave f ｓ = -sin(ω ｓ t) to the subsequent multiplier 121-1. For example, the signal wave f ｓ = -sin(ω ｓ t) is the signal wave f ｓ = -sin(nω ｓ t) to the subsequent multiplication unit 121-N.

[0044] The multiplication units 121-1 to 121-N multiply the carrier signal f distributed by the distribution unit 106. ｃ =-A ｃ sin(ω ｃ t), the signal wave f output from the multipliers 120-1 to 120-N ｓ = -sin(ω ｓ t) ~ -sin(nω ｓ t), where N is an integer equal to or greater than 1. For example, the multiplier 121-1 multiplies the carrier signal f ｃ =-A ｃ sin(ω ｃ t), the signal wave f output from the multiplier 120-1 ｓ = -sin(ω ｓ The multiplication unit 121-1 multiplies the signal A obtained by the multiplication. ｃ sin(ω ｃ t) sin(ω ｓ t) to the level adjustment unit 122-1. ｃ sin(ω ｃ t) sin(ω ｓ t) can be transformed into the following equation (1) based on the product-sum formula: cos(ω ｃ +ω ｓ )t corresponds to the first upper side wave (+J1), and -cos(ω ｃ -ω ｓ )t corresponds to the first lower side wave (-J1).

[0045]

[0046] Similarly, the multiplication unit 121-N multiplies the carrier signal f distributed by the distribution unit 106 by ｃ =-A ｃ sin(ω ｃ t), the signal wave f output from the multiplier 120-N ｓ = -sin(nω ｓ The multiplication unit 121-N multiplies the signal A obtained by the multiplication. ｃ sin(ω ｃ t) sin(nω ｓ t) to the level adjustment unit 122-N. ｃsin(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 -nω ｓ )t corresponds to the nth lower side wave (-Jn).

[0047]

[0048] 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, the output of level adjustment unit 122-1 will be referred to as [C １ ] may also be expressed as [C １ ] is expressed as the following formula (3). １ represents the amplitude after adjustment.

[0049]

[0050] 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, the output of the level adjustment unit 122-N will be referred to as [C ｎ ] may also be expressed as [C ｎ ] is expressed as the following formula (4). ｎ represents the amplitude after adjustment.

[0051]

[0052] Moreover, the signal wave f input to the distribution unit 109 ｓ = cos(ω ｓ t) is distributed by the distributor 109 and input to each multiplier 130 of the even-term sideband generating unit 113. For example, if the even-term sideband generating unit 113 includes three multipliers 130, the distributor 109 divides the signal wave f ｓ = cos(ω ｓt) to three paths leading to the three multipliers 130. As a result, each multiplier 130 receives a signal wave f ｓ = cos(ω ｓ t) is input to each multiplier 130. ｓ = cos(ω ｓ t) is converted into a frequency that is a different even multiple and output to the subsequent multiplier 131. For example, the signal wave f ｓ = cos(ω ｓ t) is doubled in frequency to produce a signal wave f ｓ = cos(2ω ｓ The signal wave f input to the multiplier 130-M is output to the multiplier 131-1 at the subsequent stage as ｓ = cos(ω ｓ t) is the signal wave f ｓ = cos(mω ｓ t) to the subsequent multiplication unit 131-M, where M is an integer of 1 or greater.

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

[0054]

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

[0056]

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

[0058]

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

[0060]

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

[0062]

[0063] Next, the reason why the modulator 10 of the embodiment has lower distortion than conventional modulators will be explained.

[0064] The reason why the modulator 10 of the embodiment has lower distortion than the conventional system is that, when comparing the frequency spectrum of the output signal from the modulator, the present embodiment is closer to the ideal frequency spectrum than the conventional system. In other words, the present embodiment can generate more sideband signal waveforms than the conventional system and the Armstrong system. While the Armstrong system has a simple configuration and allows for miniaturization and cost reduction, it can only generate sidebands within the range shown in the box in FIG. 3 (J0, ±J1). Therefore, the Armstrong system differs from the ideal PM signal waveform, which leads to deterioration of distortion characteristics and CNR characteristics. In contrast, the modulator 10 of the embodiment not only has the Armstrong system's features of a simple configuration, miniaturization, and cost reduction, but can also generate any number of sidebands (J0, ±J1, ±J2, ...). Therefore, it is possible to suppress the deterioration of distortion characteristics, which was a problem with the conventional Armstrong system. Furthermore, it is also possible to improve CNR characteristics. As a result, it is possible to extend the transmission distance and increase the number of modulation levels.

[0065] In PM modulation, the higher (deeper) the modulation index β, the wider the spectrum spreads. However, the Armstrong method cannot generate signal waveforms with sideband components of ±J2 or more, so increasing the modulation index results in a more distorted signal waveform. In contrast, the modulator 10 in this embodiment can generate signal waveforms with sideband components of ±J2 or more, so it can generate modulated signals with low distortion even with a high modulation multi-level.

[0066] (Modification 1) In the above-described embodiment, the signal wave f ｓ The case where the signal wave f ｓ In this case, a plurality of signal waves f ｓ The frequency-multiplexed signal is input to the input terminal of the distribution unit 107.

[0067] (Modification 2) In the above-described embodiment, the signal wave f ｓIn 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.

[0068] 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.

[0069] The present invention can be applied to an Armstrong modulator that performs phase modulation.

[0070] 10... modulator, 101... carrier signal generating unit, 102, 104, 106, 107, 109, 110, 111... distribution unit, 103, 108... phase adjustment unit, 105, 122-1 to 122-N, 132-1 to 132-M... level adjustment unit, 114... multiplexing unit, 120, 120-1 to 120-N, 130, 130-1 to 130-M... multiplier, 121, 121-1 to 121-N, 131, 131-1 to 131-M... multiplication unit

Claims

1. A modulator comprising: an even-term sideband generating unit that generates one or more signals having even-numbered sideband components based on a carrier signal and a signal wave to be transmitted; an odd-term sideband generating unit that generates one or more signals having odd-numbered sideband components based on the carrier signal and the signal wave; and a multiplexing unit that multiplexes the carrier signal, the one or more signals having the even-numbered sideband components, and the one or more signals having the odd-numbered sideband components.

2. The modulator according to claim 1, further comprising a first phase adjustment unit that adjusts the phase of the signal wave, wherein the odd-term sidewave generation unit generates one or more signals having odd-numbered sidewave components based on the carrier signal and the signal wave whose phase has been adjusted by the first phase adjustment unit.

3. The modulator according to claim 1 or 2, wherein the even-term side wave generating unit comprises: one or more multipliers that convert the signal wave into a different even-multiple frequency and output the converted signal wave; one or more multipliers that multiply the signal wave output from the one or more multipliers by the carrier signal; and one or more level adjuster units that adjust the level of the signal obtained by multiplication by the one or more multiplier units; and the odd-term side wave generating unit comprises: one or more multipliers that convert the phase-adjusted signal wave into a different odd-multiple frequency and output the converted signal wave; one or more multiplier units that multiply the signal wave or the phase-adjusted signal wave output from the one or more multipliers by the phase-adjusted carrier signal; and one or more level adjuster units that adjust the level of the signal obtained by multiplication by the one or more multiplier units.

4. The modulator according to claim 2, further comprising a second phase adjustment unit that rotates the phase of the carrier signal by 90 degrees, wherein the second phase adjustment unit outputs the carrier signal whose phase has been adjusted by rotating the phase of the carrier signal by 90 degrees to the odd-term side wave generation unit, and the first phase adjustment unit outputs the signal wave whose phase has been adjusted by rotating the phase of the signal wave by 90 degrees to the odd-term side wave generation unit.

5. A first division unit that divides a signal wave to be transmitted into two paths; a second division unit that divides a carrier signal into two paths; a first phase adjustment unit that adjusts the phase of the signal wave divided into the first path by the first division unit; a second phase adjustment unit that adjusts the phase of the carrier signal divided into the first path by the second division unit; an even-term sideband generation unit that generates one or more signals having even-numbered sideband components by multiplying a signal obtained by even-numbering the signal wave divided into the second path by the first division unit with the carrier signal divided into the second path by the second division unit; and an odd-term sideband generation unit that generates one or more signals having odd-numbered sideband components by multiplying a signal obtained by odd-numbering the signal wave whose phase has been adjusted by the first phase adjustment unit with the carrier signal whose phase has been adjusted by the second phase adjustment unit. a combining unit that combines one or more signals having the odd-numbered sidewave components generated by the odd-numbered sidewave generating unit and one or more signals having the even-numbered sidewave components generated by the even-numbered sidewave generating unit after level adjustment of each sidewave.

6. The even-term sideband generating unit further comprises: a third dividing unit that divides the signal wave whose phase has been adjusted by the first phase adjusting unit into two or more paths; a fourth dividing unit that divides the carrier signal whose phase has been adjusted by the second phase adjusting unit into two or more paths; a fifth dividing unit that divides the signal wave divided to the second path by the first dividing unit into two or more paths; and a sixth dividing unit that divides the carrier signal divided to the second path by the second dividing unit into two or more paths; and the even-term sideband generating unit further comprises: two or more first multipliers that convert each of the signal waves divided to the two or more paths by the fifth dividing unit into a different even-multiplied frequency and output the converted frequency; two or more first multipliers that multiply each of the even-multiplied signal waves output from the two or more first multipliers by each of the carrier signals divided to the two or more paths by the sixth dividing unit; and two or more first level adjusting units that adjust the level of each signal obtained by multiplication by each of the two or more first multipliers.

6. The phase modulator according to claim 5, wherein the odd-term sideband generating unit comprises: two or more second multipliers that convert each of the phase-adjusted signal waves distributed to two or more paths by the third distributor to a different odd-numbered multiple of the frequency and output the converted signal waves; two or more second multipliers that multiply each of the odd-numbered multiple of the signal waves output from the two or more second multipliers by the phase-adjusted carrier signal distributed to two or more paths by the fourth distributor; and two or more second level adjusting units that adjust the level of each signal obtained by multiplication by each of the two or more second multipliers.

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