Modulator and frequency modulator

Abstract

A modulator according to the present invention comprises: an even-numbered term side wave generation unit that generates one or more signals having even-numbered side wave components on the basis of a carrier signal and a signal wave to be transmitted or a signal wave subjected to a prescribed computation; an odd-numbered term side wave generation unit that generates one or more signals having odd-numbered side wave components on the basis of a carrier signal and a signal wave subjected to a prescribed computation; and a multiplexing unit that multiplexes a carrier signal, the one or more signals having even-numbered side wave components, and the one or more signals having odd-numbered side wave components.　

Description

Modulators and Frequency Modulators

[0001] The present invention relates to a modulator and a frequency 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. 6 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. 6 , 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] 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 frequency modulation signal waveform has the first and subsequent sidewave components (the second, third, fourth, etc. sidewaves in FIG. 7) as shown in FIG. 7. 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 or the signal wave on which a predetermined operation has been performed; 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 on which a predetermined operation has been performed; 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 is an even-numbered multiplication circuit that generates one or more signals having even-numbered sideband components by multiplying a signal obtained by even-numbering the signal wave distributed to the second path by the first distributor by the carrier signal distributed to the second path by the second distributor, the even-numbered multiplication circuit including a first distributor that distributes a signal wave to two paths, a second distributor that distributes a carrier signal to two paths, an operational integrator that performs a predetermined operation on the signal wave distributed to the first path by the first distributor, a phase adjustment unit that adjusts the phase of the signal wave distributed to the first path by the second distributor, and an even-numbered multiplication circuit that generates one or more signals having even-numbered sideband components by multiplying a signal obtained by even-numbering the signal wave distributed to the second path by the first distributor by the carrier signal distributed to the second path by the second distributor. an odd-term sideband generating unit that generates one or more signals having odd-numbered sideband components by multiplying the signal wave that has been subjected to a predetermined operation by the arithmetic unit by an odd-numbered multiplication factor and the carrier signal whose phase has been adjusted by the phase adjusting unit; and a combining unit that combines the one or more signals having odd-numbered sideband components generated by the odd-term sideband generating unit and the one or more signals having even-numbered sideband components generated by the even-term sideband generating unit after level adjustment of each sideband.

[0010] One aspect of the present invention includes a computing unit that performs a predetermined operation on a signal wave to be transmitted, a first dividing unit that divides the signal wave that has been subjected to the predetermined operation by the computing unit into two paths, a second dividing unit that divides a carrier signal into two paths, a first phase adjusting unit that adjusts the phase of the carrier signal distributed to the first path by the second dividing unit, an odd-term sideband generating unit that generates one or more signals having odd-numbered sideband components by multiplying a signal obtained by odd-numbering the signal wave that has been subjected to the predetermined operation and distributed to the first path by the first dividing unit by the carrier signal whose phase has been adjusted by the first phase adjusting unit, and a second phase adjustment unit that adjusts the phase of the distributed signal wave after a predetermined operation; 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 after a predetermined operation whose phase has been adjusted by the second phase adjustment unit by a carrier signal distributed to a second path by the second distribution unit; and a multiplexing unit that multiplexes the one or more signals having odd-numbered sideband components generated by the odd-term sideband generation unit and the one or more signals having even-numbered sideband components generated by the even-term sideband generation unit after level adjustment of each sideband of each signal.

[0011] According to the present invention, it is possible to suppress deterioration of the distortion characteristics of the modulated output signal.

[0012] FIG. 1 is a configuration diagram of a modulator 10 according to a first embodiment. FIG. 2 is a diagram for explaining a problem of the first embodiment. FIG. 3 is a configuration diagram of a modulator 10a according to a second embodiment. FIG. 4 is a diagram for explaining how to properly use the first embodiment and the second embodiment. FIG. 5 is a configuration diagram of a modulator 10b according to a third embodiment. FIG. 6 is a diagram showing an example of the configuration of a modulator 90 according to the prior art. FIG. 7 is a diagram showing an example of a signal waveform of an ideal phase modulation method.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] 1 is a configuration diagram of a modulator 10 according to a first 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, an integrator 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.

[0015] 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.

[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 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.

[0019] 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.

[0020] 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 two 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.

[0021] The distributor 107 receives a signal wave. The signal wave is a signal to be transmitted. The distributor 107 distributes the input signal wave. For example, the distributor 107 distributes the input signal wave into two paths. In this case, the distributor 107 distributes the signal wave into a first path and a second path. An integrator 108 is connected to the first path distributed by the distributor 107, and a distributor 109 is connected to the second path distributed by the distributor 107. The distributor 107 is one aspect of the first distributor. The signal wave distributed by the distributor 107 is input to the integrator 108 and the distributor 109.

[0022] The integrator 108 receives the signal wave distributed by the distributor 107. The integrator 108 integrates the received signal wave. The signal wave integrated by the integrator 108 is input to the distributor 111.

[0023] 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.

[0024] 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.

[0025] The distributor 111 receives the signal wave integrated by the integrator 108. The distributor 111 distributes the received signal wave to two or more paths. The distributor 111 is one aspect of a third distributor. The signal wave distributed by the distributor 111 is input to the odd-term sideband generating unit 112.

[0026] 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.

[0027] 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.

[0028] The multipliers 120 convert each of the signal waves distributed by the distributor 111 into a frequency that is a different odd multiple 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 into a frequency that is 1x the original frequency and outputs the converted signal waves, the multiplier 120-2 converts the signal waves distributed by the distributor 111 into a frequency that is 3x the original frequency and outputs the converted signal waves, and the multiplier 120-3 converts the signal waves distributed by the distributor 111 into a frequency that is 5x the original frequency and outputs the converted signal waves. Here, n is an odd number greater than or equal to 1. The multipliers 120 are one aspect of a second multiplier.

[0029] The multiplier 121 multiplies the signal wave 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.

[0030] 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.

[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 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.

[0034] The multiplier 131 multiplies the signal 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. The multiplier 131 is one aspect of a first multiplier.

[0035] 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.

[0036] 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.

[0037] The spectrum of a phase-modulated waveform (PM waveform) (such as the waveform shown in FIG. 7 ) is uniquely determined once parameters such as the modulation index are determined, and the amplitude of each sideband is also uniquely determined. Therefore, as an example of a level adjustment method in each of the level adjustment units 105, 122, and 132 in the above-described embodiment, each of the level adjustment units 105, 122, and 132 adjusts the level so that it is equal to the magnitude of this ideal amplitude component of each sideband. This also applies to the following embodiments.

[0038] (Operation of Modulator in First Embodiment) 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).

[0039] The carrier signal generating section 101 of the modulator 10 generates a carrier signal f ｃ = A ｃ cos(ω ｃ t) is output from the carrier signal generating unit 101. ｃ =A ｃ cos(ω ｃ t) is divided by the dividing unit 102 and input to the phase adjusting unit 103 and dividing unit 104. The carrier signal f ｃ = A ｃ cos(ω ｃ t) is distributed by the distribution unit 104 and input to the level adjustment unit 105 and distribution unit 110.

[0040] The level adjustment unit 105 adjusts the input carrier signal f ｃ = A ｃ cos(ω ｃ t) and outputs the adjusted amplitude level. For simplicity of explanation, 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.

[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(ωｃ 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.

[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 divided by the dividing unit 107 and input to the integrator 108 and dividing unit 109. The integrator 108 divides 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 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 fｓ = (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.

[0044] Each multiplier 120 multiplies the input signal wave f ｓ = (1 / ω 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 = (1 / ω ｓ ) sin(ω ｓ t) is the signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ t) to the subsequent multiplier 121-1. For example, the signal wave f ｓ = (1 / ω ｓ ) sin(ω ｓ t) is the signal wave f ｓ = (1 / ω ｓ ) sin(nω ｓ t) to the subsequent multiplication unit 121-N.

[0045] 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 / ωｓ ) 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).

[0046]

[0047] 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 -nω ｓ )t corresponds to the nth lower side wave (-Jn).

[0048]

[0049] 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.

[0050]

[0051] 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.

[0052]

[0053] 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 ｓ t) to three paths leading to the three multipliers 130. As a result, each multiplier 130 receives a signal wave f ｓ = cos(ω ｓ Each multiplier 130 multiplies the input signal wave f ｓ = cos(ω ｓ t) is multiplied by an even number and output to the subsequent multiplier 131. For example, the signal wave f ｓ = cos(ω ｓ t) is doubled in frequency to produce a signal wave f ｓ = cos(2ω ｓThe 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.

[0054] 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(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).

[0055]

[0056] 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-Mｓ = 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).

[0057]

[0058] 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.

[0059]

[0060] 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.

[0061]

[0062] The modulator 10 converts [A] and [B] obtained by the above processing. ２ ]~[Bｍ ] 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 10 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.

[0063]

[0064] Next, the reason why the modulator 10 of the embodiment has lower distortion than conventional modulators will be explained.

[0065] 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. 7 (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 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 degradation 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.

[0066] 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.

[0067] Second Embodiment A configuration for solving the problems that arise in the second embodiment will be described.

[0068] Before describing the configuration of the second embodiment, the problem with the first embodiment will be described. In general FM modulation, including the Armstrong method, a signal wave f ｓ An integrator is used to integrate the signal. This is because in FM modulation, the signal wave is not simply placed on the phase component (as in PM modulation), but rather the FM modulation process is only achieved by placing the integrated signal as the phase component. Conversely, if integration is not performed, it becomes PM modulation instead of FM modulation.

[0069] More specifically, the signal wave f ｓ is a simple cosine wave of a single wavelength, but in actual information transmission, the signal wave f ｓ is a signal with a bandwidth as shown in Figure 2(A). Therefore, a signal wave f ｓ When the signal f shown in FIG. 2A is input, the integrated signal has a value with an amplitude gradient on the frequency axis as shown in FIG. 2B. However, in the first embodiment, the even-term sideband generating unit 113 does not include an integrator. As a result, the amplitude gradient shown in FIG. 2B does not occur, and deviation from the ideal FM waveform occurs, which is expected to result in quality degradation. Note that the signal wave f shown in FIG. 2A ｓ When the bandwidth of the signal wave f shown in FIG. ｓ is the signal wave f shown in FIG. ｓ Therefore, even in the first embodiment, an FM signal can be generated without significant degradation. However, when a wideband signal is converted into an FM signal, the signal wave f ｓ Therefore, in the second embodiment, the signal wave f ｓ The configuration in which the above can be input will be described.

[0070] 3 is a configuration diagram of a modulator 10a according to the second embodiment. The modulator 10a includes a carrier signal generating unit 101, a dividing unit 102, a phase adjusting unit 103, a dividing unit 104, a level adjusting unit 105, a dividing unit 106, a dividing unit 107, an integrator 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, a combining unit 114, and a phase adjusting unit 115.

[0071] Modulator 10a differs in configuration from modulator 10 in that integrator 108 is provided on the input terminal side (the side to which the signal wave is input) of distributor 107, and in that it newly includes phase adjustment unit 115. The following description will focus on the differences from modulator 10.

[0072] The signal wave is input to the integrator 108. The integrator 108 integrates the input signal wave. The signal wave integrated by the integrator 108 is input to the distributor 107.

[0073] The distributor 107 receives the signal wave integrated by the integrator 108. The distributor 107 distributes the input integrated signal wave. For example, the distributor 107 distributes the input signal wave into two. In this case, the distributor 107 distributes the signal wave into a first path and a second path. In the second embodiment, 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.

[0074] 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.

[0075] 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.

[0076] 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. The signal wave divided by the dividing unit 109 is input to the even-term sideband generating unit 113.

[0077] (Operation of Modulator in Second Embodiment) With the above configuration, the modulator 10a operates as follows. Note that there are cases where explanations of components that perform the same processing as in the first embodiment (for example, the odd-term sideband generating unit 112, etc.) are omitted. 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).

[0078] The carrier signal generating section 101 of the modulator 10 generates a carrier signal f ｃ =A ｃ cos(ω ｃ t) is output from the carrier signal generating unit 101. ｃ =A ｃ cos(ω ｃ t) is divided by the dividing unit 102 and input to the phase adjusting unit 103 and dividing unit 104. The carrier signal f ｃ =A ｃ cos(ω ｃ t) is distributed by the distribution unit 104 and input to the level adjustment unit 105 and distribution unit 110.

[0079] The level adjustment unit 105 adjusts the input carrier signal f ｃ =A ｃ cos(ω ｃThe phase adjuster 103 adjusts the amplitude level 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 distribution unit 106 and input to each multiplication unit 121 of the odd-term sideband generation unit 112.

[0080] The carrier signal f input to the distribution unit 110 ｃ =A ｃ cos(ω ｃ The signal wave f t) is divided by the dividing unit 110 and input to each multiplier 131 of the even-term sideband generating unit 113. ｓ = cos(ω ｓ t) is integrated by the integrator 108 to obtain 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 phase adjusting section 115 and dividing section 111.

[0081] The signal wave f input to the distribution unit 111 ｓ = (1 / ω ｓ ) sin(ω ｓ t) is distributed by the distribution unit 111 and input to each multiplier 120 of the odd-term sideband generation unit 112. Note that the processing of the odd-term sideband generation unit 112 is the same as in the first embodiment, and therefore will not be described here.

[0082] 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 / ωｓ ) cos(ω ｓ t) is converted into a signal wave f ｓ = (1 / ω ｓ ) cos(ω ｓ t) is divided by the dividing section 109 and input to each multiplier 130 of the even-term sideband generating section 113.

[0083] 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 signal wave f ｓ = (1 / ω ｓ ) cos(ω ｓ t) is doubled in frequency to produce a signal wave f ｓ = (1 / ω 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 = (1 / ω ｓ ) cos(ω ｓ t) is the signal wave f ｓ = (1 / ω ｓ ) cos(mω ｓ t) to the subsequent multiplication unit 131-M.

[0084] 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(2ωｓ The 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 (10) 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).

[0085]

[0086] 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 (11) 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).

[0087]

[0088] 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 signals. 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 signals. The output [B ２ ] is expressed as in the above equation (7). 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. The output [B ｍ ] is expressed as in the above equation (8).

[0089] 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 as in equation (9). Note that the amplitude of each sideband of the FM signal is uniquely determined according to the set modulation index.

[0090] (How to Use the First and Second Embodiments) Here, we will explain how to use the first and second embodiments. The first embodiment uses fewer elements (the number of blocks in the block diagram) than the second embodiment, resulting in a simpler configuration. On the other hand, because an integrator is not used for the signal wave input to the even-term sideband generating unit 113, no slope is imparted to the amplitude of the spectrum of the signal wave, and the generated FM signal is slightly distorted compared to an ideal FM waveform. However, if the signal wave to be transmitted is a narrowband signal, the slope can be relatively ignored.

[0091] Figure 4A shows an example of a wideband signal, and Figure 4B shows an example of a narrowband signal. In the case of a wideband signal, as shown in Figure 4A, the difference in amplitude between the left and right ends of the spectrum after passing through the integrator is large, so even if you try to substitute this waveform with a signal that has not passed through the integrator (a signal with flat amplitude), a large error will occur. However, in the case of a narrowband signal, as shown in Figure 4B, the difference in amplitude between the left and right ends of the spectrum after passing through the integrator is small, so this waveform can be satisfactorily substituted with a signal that has not passed through the integrator (a signal with flat amplitude). Therefore, the first embodiment is particularly effective when the signal wave to be transmitted is narrowband, while the second embodiment is preferable when transmitting a wideband signal.

[0092] The modulator 10a of the second embodiment configured as described above can achieve the same effects as those of the first embodiment. Furthermore, in the modulator 10a, the signal wave input to the even-term sideband generating unit 113 is integrated by the integrator 108. This allows a slope to be applied to the amplitude of the spectrum of the signal wave input to the even-term sideband generating unit 113, and the generated FM signal can be made closer to an ideal FM waveform than in the first embodiment. Therefore, it is possible to suppress deterioration of distortion characteristics more than in the first embodiment.

[0093] In the second embodiment, the number of level adjustment units provided corresponds to the number of multiplication units provided in the even-term sideband generating unit and the odd-term sideband generating unit, respectively. In the third embodiment, a configuration will be described in which the number of level adjustment units provided in the modulator is reduced.

[0094] 5 is a configuration diagram of a modulator 10b according to the third embodiment. The modulator 10b includes a carrier signal generating unit 101, a dividing unit 102, a phase adjusting unit 103, a dividing unit 104, a level adjusting unit 105, a dividing unit 106, a dividing unit 107, an integrator 108, a dividing unit 109, a dividing unit 110, a dividing unit 111, an odd-term sideband generating unit 112b, an even-term sideband generating unit 113b, a multiplexing unit 114, and a phase adjusting unit 115.

[0095] The modulator 10b differs in configuration from the modulator 10a in the second embodiment in that it includes an odd-term sidewave generating unit 112b and an even-term sidewave generating unit 113b instead of the odd-term sidewave generating unit 112 and the even-term sidewave generating unit 113. The following description will focus on the differences from the modulator 10a.

[0096] The odd-term sideband generating unit 112b is composed of one or more multipliers 120, one or more multipliers 121, one level adjuster 122, and one adder 123. The adder 123 adds the signals output from the one or more multipliers 121. The adder 123 outputs the signal obtained by the addition to the level adjuster 122. The level adjuster 122 adjusts the level of the signal output from the adder 123.

[0097] The even-term sideband generating unit 113b is composed of one or more multipliers 130, one or more multipliers 131, one level adjuster 132, and one adder 133. The adder 133 adds the signals output from the one or more multipliers 131. The adder 133 outputs the signal obtained by the addition to the level adjuster 132. The level adjuster 132 adjusts the level of the signal output from the adder 133.

[0098] The modulator 10b of the third embodiment configured as described above can achieve the same effects as those of the second embodiment. Furthermore, the modulator 10b includes a level adjustment unit 122 that performs common level adjustment in the odd-term sideband generating unit 112b and a level adjustment unit 132 that performs common level adjustment in the even-term sideband generating unit 113b. This allows the number of level adjustment units included in the modulator 10b to be reduced. As a result, the device cost of the modulator 10b can be reduced.

[0099] (Modification 1 common to the first to third embodiments) In each of the above-described embodiments, the signal wave f ｓ The case where the signal wave f ｓ In this case, a plurality of signal waves f ｓFor example, in the first embodiment, the frequency-multiplexed signal may be input from the input terminal of the distributor 107, and in the second and third embodiments, the frequency-multiplexed signal may be input from the input terminal of the integrator 108.

[0100] (Modification 2 common to the first to third embodiments) In each of the above-described embodiments, the signal wave f ｓ In the description of each embodiment and each formula, 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.

[0101] (Variation 3 common to the first to third 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.

[0102] 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.

[0103] The present invention can be applied to an Armstrong modulator that performs frequency modulation.

[0104] 10, 10a, 10b... 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, 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, 133... addition 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 or the signal wave on which a predetermined operation has been performed; 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 on which a predetermined operation has been performed; 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 carrier signal, wherein the odd-term sideband generation unit generates one or more signals having odd-numbered sideband components based on the carrier signal whose phase has been adjusted by the first phase adjustment unit and the signal wave on which a predetermined operation has been performed.

3. A modulator according to claim 1 or 2, further comprising a second phase adjustment unit that adjusts the phase of the signal wave after a predetermined calculation has been performed, wherein the even-term side wave generation unit generates one or more signals having even-numbered side wave components based on the carrier signal and the signal wave whose phase has been adjusted by the second phase adjustment unit.

4. 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 or the signal wave that has been subjected to a predetermined operation into a different even-number multiple of a 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 adjustment units that adjust the level of the signal obtained by multiplication by the one or more multipliers; and the odd-term side wave generating unit comprises: one or more multipliers that convert the phase-adjusted signal wave into a different odd-number multiple of a frequency and output the converted signal wave; one or more multipliers 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 adjustment units that adjust the level of the signal obtained by multiplication by the one or more multipliers.

5. The modulator according to claim 4, wherein the even-term sideband generating section further comprises an adder section that adds together the signals obtained by multiplication by the one or more multiplier sections, and the one or more level adjustment sections adjust the level of the signals after addition by the adder section; and the odd-term sideband generating section further comprises an adder section that adds together the signals obtained by multiplication by the one or more multiplier sections, and the one or more level adjustment sections adjust the level of the signals after addition by the adder section.

6. 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 calculator that performs a predetermined calculation on the signal wave divided into the first path by the first division unit; a phase adjustment unit that adjusts the phase of the signal wave 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 that has been subjected to the predetermined calculation by the calculator with the carrier signal whose phase has been adjusted by the 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.

7. A computing unit that performs a predetermined operation on a signal wave to be transmitted; a first dividing unit that divides the signal wave that has been subjected to the predetermined operation by the computing unit into two paths; a second dividing unit that divides a carrier signal into two paths; a first phase adjusting unit that adjusts the phase of the carrier signal distributed to the first path by the second dividing unit; an odd-term sideband generating unit that generates one or more signals having odd-numbered sideband components by multiplying a signal obtained by odd-numbering the signal wave that has been subjected to the predetermined operation and distributed to the first path by the first dividing unit with the carrier signal whose phase has been adjusted by the first phase adjusting unit; a second phase adjusting unit that adjusts the phase of the signal wave that has been subjected to the predetermined operation and distributed to the second path by the first dividing unit; and an even-term sideband generating unit that generates one or more signals having even-numbered sideband components by multiplying a signal obtained by even-numbering the signal wave that has been subjected to the predetermined operation and whose phase has been adjusted by the second phase adjusting unit with the carrier signal distributed to the second path by the second dividing 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.

8. The system further comprises: a third divider that divides the signal wave that has been subjected to a predetermined calculation by the calculator into two or more paths; a fourth divider that divides the phase-adjusted carrier signal into two or more paths; a fifth divider that divides the signal wave divided by the first divider to the second path into two or more paths; and a sixth divider that divides the carrier signal divided by the second divider to the second path into two or more paths; wherein the even term sideband generation unit comprises: two or more first multipliers that convert each of the signal waves divided to the two or more paths by the fifth divider to a different even multiple of frequency and output the converted signal wave; two or more first multipliers that multiply each of the even multiple of 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 divider; and two or more first level adjusters that adjust the level of each signal obtained by multiplication by each of the two or more first multipliers; and wherein the odd term sideband generation unit comprises:

8. The frequency modulator according to claim 6, comprising: two or more second multipliers that convert each of the signal waves after a predetermined operation distributed to two or more paths by the third distribution unit into a different odd-numbered multiple of a frequency and output the converted signal waves; two or more second multipliers that multiply each of the odd-numbered multiple of a frequency output from the two or more second multipliers by the phase-adjusted carrier signal distributed to two or more paths by the fourth distribution unit; and two or more second level adjusters that adjust the level of each signal obtained by multiplication by each of the two or more second multipliers.

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