JP3725307B2 - BPSK modulator - Google Patents

Description

【００１３】
またスイッチに入射した電波が反射され、サーキュレータにより迂回線路を経由し方向性結合器を介して出力端に導かれるときの電力は（数２）となる。
【００１４】
【数２】

【００１５】
そこで、方向性結合器の結合度Ｃを（数１）式と（数２）式が等しいと仮定したときに得られる（数３）式の値に設定することにより、ＢＰＳＫ変調時において、両経路での出力レベルを一定に保つことができる。
【００１６】
【数３】

【００１７】
請求項２に記載の発明は、前記位相線路の長さを任意の長さに設定し、前記サーキュレータの前記第１の端子から入力され第２の端子から出力される搬送波の一部が前記スイッチを透過し、前記搬送波電力の残りの一部が前記スイッチで反射されるように前記スイッチを設定した状態で、前記ＢＰＳＫ変調器の透過損を測定し、その結果得られるヌル点のなかでも、所望の周波数よりも低くなおかつ最も所望の周波数に近いヌル点での波長をλaとし、所望の周波数よりも高くなおかつ最も所望の周波数に近いヌル点での波長をλbとし、所望の周波数での波長をλ０とすると、前記位相線路の長さを前記ＢＰＳＫ変調器の透過損の測定時に設定した任意の長さからλb（λa−λ０）／（λa−λb）短くしたものである。
【００１８】
この構成において、スイッチを透過する電力とスイッチで反射される電力が同時に存在するようにスイッチを設定することにより、スイッチを透過し透過線路と方向性結合器を経て出力端に導かれる電波の経路と、スイッチで反射されサーキュレータにより迂回線路を経て方向性結合器を介して出力端に導かれる電波の経路の差が半波長の奇数倍となる周波数では、両経路を伝搬してきた電波は位相が１８０°異なるために、出力レベルは他の周波数に対して急峻に減少する。両経路の経路差をΔｌ、またmを任意の整数とすると、（数４）、（数５）となる。
【００１９】
【数４】

【００２０】
【数５】

【００２１】
また所望の周波数で１８０°の位相差を得る為に短くすべき迂回線路の長さをαとすると、（数６）の関係式が成り立つ。
【００２２】
【数６】

【００２３】
したがって上記（数４）、（数５）、（数６）式からαは（数７）として求められる。
【００２４】
【数７】

【００２５】
したがってＢＰＳＫ変調器の透過損の周波数特性から所望の周波数で１８０°の位相差を得る為に短くすべき迂回線路長を容易に算出することができるという作用を有する。
【００２６】
以下、本発明の実施の形態について説明する。図１は本発明の一実施の形態によるＮＲＤガイドＢＰＳＫ変調器の斜視図を示すものであり、図２は同ＮＲＤガイドＢＰＳＫ変調器で使用している方向性結合器の斜視図である。図１において、１２と１２’は導体板である。１と１’はフェライトディスクであり、２は２枚のフェライトディスク１，１’を支持する誘電体チューブである。３ａ，３ｂ，３ｃは不要モードを抑制するためのモードサプレッサであり、４と４’はフェライトディスク１，１’、誘電体チューブ２と同心軸上に配置した磁石であり、フェライトディスク１，１’と誘電体チューブ２及びモードサプレッサ３ａ，３ｂ，３ｃと共にサーキュレータを構成する。
【００２７】
５はサーキュレータの一端に接続した入力線路であり、６は出力線路である。１０は半導体素子を装荷したマウントであり、半導体スイッチとして機能する。９は高誘電率薄板であり、８は整合線路である。７はモードサプレッサ３ｂと整合線路８の間に設けた空隙であり、高誘電率薄板９と整合線路８とともにその長さにより、マウント１０を電波が透過するようにベースバンド信号を印加したときの、マウント１０での反射電力を抑える。１１はマウントに装荷したＰＩＮダイオード等の半導体へバイアス電圧を印加するためのベースバンド信号入力端子である。
【００２８】
１３と１３’は位相差調整線路であり、１４は１８０°ベンドであり、１５は７５°ベンドである。１６は７５°ベンド１５に接続した無反射終端器である。１８はＢＰＳＫ変調器の出力端である。なお、出力線路６と７５°ベンド１５は、両線路の最接近部で方向性結合器を形成しており、また位相差調整線路１３と１８０°ベンド１４と位相差調整線路１３’及び７５°ベンド１５で迂回線路を形成する。
【００２９】
図２において、１８は出力線路６の一部で、マウント１０に接続する方向性結合器の入力端であり、１９は７５°ベンド１５の一部である方向性結合器の入力端であり、２０は出力線路１２の一部で出力端１７に接続する方向性結合器の出力端であり、２１は７５°ベンド１５の一部で無反射終端器１６に接続する方向性結合器の出力端である。
【００３０】
以上のように構成されたＮＲＤガイドＢＰＳＫ変調器の動作について説明する。変調器への電波の入射は入力線路５から行われる。入射された電波は、フェライトディスク１，１’と誘電体チューブ２と、モードサプレッサ３ａ，３ｂ，３ｃ及び磁石４，４’で構成されるサーキュレータにより、ＰＩＮダイオード等の半導体が装荷されており、入射した電波の透過と反射を切り換えるスイッチとして機能するマウント１０に導かれる。ベースバンド信号入力端子１１からマウント１０に装荷された半導体素子に印加されるベースバンド信号により、マウント１０に入射した電波の透過と反射を切り換えるが、透過した場合には、方向性結合器を介して出力線路６に到達する。マウント１０で電波が反射された場合には、サーキュレータにより迂回線路を伝送し、方向性結合器を介して出力線路６に到達する。
【００３１】
ここで、予めマウント１０を透過して出力端１７に到達する電波の経路と、マウント１０で反射されサーキュレータにより迂回線路を経て出力端１７に達する電波の経路の差が半波長の奇数倍になるように位相差調整線路１３，１３’を設定しておくことで、マウント１０に装荷した半導体素子に印加するベースバンド信号で出力波の位相を１８０°切り換え、ＢＰＳＫ変調を行うことができる。また、マウント１０を電波が透過するようにバイアス電圧を印加したときのマウント１０の透過損Lt（dB）と方向性結合器の結合度Ｃ（dB）から、マウント１０に入射した電波が、マウント１０を透過した後に方向性結合器の入力端１８から方向性結合器の出力端２０を通過して出力端１７に達する電力の大きさはは、マウント１０に入射する電力の大きさを１とした場合に、（数８）で表すことができる。
【００３２】
【数８】

【００３３】
またマウント１０で電波が反射するようにベースバンド信号を設定したときの、マウント１０での反射損Lr（dB）とサーキュレータの挿入損Lc（dB）から、マウント１０に入射した電波がマウント１０で反射され、位相差調整線路１３、１８０°ベンド１４、位相差調整線路１３’、及び方向性結合器を介して出力端１７に達する電力の大きさは、マウント１０に入射する電力の大きさを１としたときに、（数９）で表すことができる。
【００３４】
【数９】

【００３５】
ここで２つの値を等しいとして得られる（数１０）式の値に、方向性結合器の結合度Ｃを設定することで、２つの経路を切り換えたときの出力端１７での出力の変動をなくすことができる。
【００３６】
【数１０】

【００３７】
ここで方向性結合器の結合度とは、方向性結合器の入力端１８から入射する電波をＰＩＮとし、方向性結合器の出力端２１から出力される電力をPoutとしたとき、あるいは方向性結合器の入力端１９から入射する電力をＰＩＮとし、方向性結合器の出力端２０から出力される電力をPoutとしたときに、（数１１）式で定義される値を示す。
【００３８】
【数１１】

【００３９】
次に位相差調整線路の長さの決定方法について、ＢＰＳＫ変調器の透過損の周波数特性を示す図３を用いて説明する。図３は、本発明の一実施の形態よるＮＲＤガイドＢＰＳＫ変調器の透過損の周波数特性図である。図１に示すＢＰＳＫ変調器において、マウント１０に入射した電波がマウント１０を透過する電力と、マウント１０で反射される電力が同時に存在するように、マウント１０に装荷した半導体素子に印加するベースバンド信号を設定して、透過損の周波数特性を測定した場合には、マウント１０を透過して出力端１７に達する電波とマウント７で反射し位相差調整線路１３、１８０°ベンド１４、位相差調整線路１３’、７５°ベンド１５及び方向性結合器を介して出力端１７に達する電波の経路差が半波長の奇数倍となる周波数２２，２３，２４，２５で、ヌル点２７，２８，２９，３０が生じる。経路差をΔｌとし、周波数２３での波長をλaとし、周波数２４での波長をλbとし、またｍを任意の整数とすると、（数１２）式と（数１３）式の関係が成り立つ。
【００４０】
【数１２】

【００４１】
【数１３】

【００４２】
また、所望の周波数２６でヌル点が生じさせるために、短くすべき伝送経路差をαとし、所望の周波数２６での波長をλ０とすると、（数１４）となる。
【００４３】
【数１４】

【００４４】
（数１２）、（数１３）、（数１４）式からαを（数１５）として求めることができる。
【００４５】
【数１５】

【００４６】
暫定的に長さを定めた位相差線路１４，１４’を（数１５）式のαの長さだけ短くすることにより所望の周波数２６での２つの経路の位相差を１８０°に設定することができ、マウント１０に装荷した半導体素子へのベースバンド信号で、出力波の位相を１８０°切り換えることができる。なお、ここでは暫定的に定めた位相差調整線路１３，１３’の短くすべき長さの算出方法について説明したが、伸ばすべき伝送経路差長をβとして（数１４）式の代わりに（数１６）式を用いて得られる（数１７）式の長さだけ位相差調整線路１３、１３’の長さを長くしてもよい。
【００４７】
【数１６】

【００４８】
【数１７】

【００４９】
以上のように、本実施の形態ではマウント１０に入射し透過した電波と、マウント１０で反射された電波の両者が方向性結合器を介して出力端１７に導かれる為、方向性結合器の結合度を（数１８）と設定することにより、２つの経路を切り換えたときの出力レベルを一定に保つことができる。
【００５０】
【数１８】

【００５１】
また、暫定的に長さを定めた位相差調整線路１３，１３’を、変調器の透過損の周波数特性から得られるヌル点２８，２９での波長と１８０°の位相差を得たい所望の周波数２６の波長から、短くすべき位相差調整線路１３，１３’の長さを（数１９）と求めることができ、一度ＢＰＳＫ変調器の透過損の周波数特性を測定するだけで、短くすべき位相差調整線路１３，１３’の長さを算出することができる。
【００５２】
【数１９】

【００５３】
【発明の効果】
以上の本発明によれば、出力波の位相を１８０°切り換えたときの出力レベルの変動をなくすことができる。また、２つの伝送経路の経路差の調整を、ＢＰＳＫ変調器の透過損の周波数特性の測定データから容易に算出できる。
【図面の簡単な説明】
【図１】本発明の一実施の形態よるＮＲＤガイドＢＰＳＫ変調器の斜視図
【図２】本発明の一実施の形態よるＮＲＤガイドＢＰＳＫ変調器で使用している方向性結合器の斜視図
【図３】本発明の一実施の形態よるＮＲＤガイドＢＰＳＫ変調器の透過損の周波数特性図
【図４】従来のＢＰＳＫ変調器のブロック図
【符号の説明】
１，１’ フェライトディスク
２ 誘電体チューブ
３ａ，３ｂ，３ｃ モードサプレッサ
４，４’ 磁石
５ 入力線路
６ 出力線路
７ 空隙
８ 整合線路
９ 高誘電率薄板
１０ マウント
１１ ベースバンド信号入力端子
１２，１２’ 導体板
１３，１３’ 位相差調整線路
１４ １８０°ベンド
１５ ７５°ベンド
１６ 無反射終端器
１７ 出力端
１８，１９ 方向性結合器の入力端
２０，２１ 方向性結合器の出力端
２２〜２５ 周波数
２６ 所望の周波数
２７〜３０ ヌル点
３１ 搬送波入力端子
３２ サーキュレータ
３３ 高域通過フィルタ
３４ 低域通過フィルタ
３５ ＰＩＮダイオード
３６ 反射板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a BPSK modulator that obtains a 180 ° phase difference of a modulated wave by switching paths.
[0002]
[Prior art]
Conventionally, PSK (Phase Shift Keying) modulation has been widely used as a modulation scheme having better transmission efficiency than ASK (Amplitude Shift Keying) modulation, and a BPSK (Binary Phase Shifting) modulator also in a high frequency band such as a millimeter wave. The demand for is increasing.
[0003]
A conventional BPSK modulator will be described below. FIG. 4 shows a block diagram of a conventional BPSK modulator. In FIG. 4, 11 is a baseband signal input terminal, and 31 is a carrier wave input terminal. 32 is a circulator. Reference numeral 33 denotes a high-pass filter, and reference numeral 34 denotes a low-pass filter. 35 is a PIN diode, and 36 is a reflector. Reference numeral 17 denotes an output terminal of the BPSK modulator.
[0004]
The operation of the conventional BPSK modulator configured as described above will be described. The carrier wave input from the carrier wave input terminal 31 passes through the high-pass filter 33 by the circulator 32 and reaches the PIN diode 35. The conduction and non-conduction of the PIN diode 35 are switched by a baseband signal that is input from the baseband signal input terminal 11 and applied through the low-pass filter 34.
[0005]
Here, when the PIN diode 35 is non-conductive, the carrier wave is reflected by the PIN diode 35 and reaches the output end 17 via the circulator 32. On the other hand, when the PIN diode 35 is conductive, it passes through the PIN diode 35 and is reflected by the reflecting plate 36, passes through the PIN diode 35 again, and reaches the output end 17 via the circulator 32. Here, by setting the reciprocal path between the PIN diode 35 and the reflector 36 so as to correspond to the phase π, the BPSK modulation can be performed by switching between conduction and non-conduction of the PIN diode 35 by the baseband signal. .
[0006]
[Problems to be solved by the invention]
However, although the conventional BPSK modulator has an advantage that BPSK modulation can be performed with a simple circuit configuration, a loss caused when the carrier wave passes through the PIN diode 35 causes the BPSK modulator when the PIN diode 35 is conductive. And the output of the BPSK modulator during non-conduction are different.
[0007]
An object of the present invention is to provide a BPSK modulator having a simple structure that can solve the above-mentioned conventional problems.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, a BPSK modulator according to the present invention includes a first terminal, a second terminal,
A circulator having three terminals, a third terminal, whose rotation direction is in the order of the first terminal, the second terminal, and the third terminal, and one end connected to the first terminal of the circulator An input line, a switch having two terminals, one terminal connected to the second terminal of the circulator, a phase line having one end connected to the third terminal of the circulator, a first A directional coupling having a line and a second line, wherein one end of the first line is connected to another terminal of the switch, and one end of the second line is connected to the other end of the phase line A non-reflective terminator connected to the other end of the first line or the second line of the directional coupler, and the directional coupler not connected to the non-reflective terminator Connected to the other end of the first line or the second line Constituted by the output line, by inputting the baseband signal to the switch, the transmission path of the carrier wave inputted from the first terminal of the circulator switched by said switch, also coupling degree of the directional coupler Thus, the output power from the output line is kept constant.
[0009]
With this configuration, only by measuring the frequency characteristic of the transmission loss of the BPSK modulator in a detour path having an arbitrary length once, the detour path length to be shortened to obtain a phase difference of 180 ° at a desired frequency can be obtained. Can be sought.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 has three terminals of a first terminal, a second terminal, and a third terminal, and the rotation direction is the first terminal, the second terminal, and the third terminal. A switch having one end connected to the second terminal of the circulator, an input line having one end connected to the first terminal of the circulator, and one terminal connected to the second terminal of the circulator, A phase line having one end connected to the third terminal of the circulator, a first line and a second line, one end of the first line being connected to another terminal of the switch; A directional coupler having one end of the second line connected to the other end of the phase line, and a non-reflective connected to the first line of the directional coupler or the other end of the second line. Terminator and the directional coupling to which the non-reflective terminator is not connected The first line or the output line connected to the other end of the second line, the transmission path of the carrier wave input from the first terminal of the circulator is switched by the switch, and the direction The output power from the output line is kept constant depending on the degree of coupling of the sex coupler.
[0011]
In this configuration, there are a path that passes through the switch and is guided to the output end via the directional coupler, and a path that is reflected by the switch and then is routed to the output end via the directional coupler by way of the circulator. The difference is set in advance to be an odd multiple of a half wavelength, and the BPSK modulation is performed by switching the transmission state and the reflection state of the switch with the baseband signal. Here, the transmission loss of the radio wave incident on the switch when the switch is in the radio wave transmission state is Lt (dB), and the reflection loss of the radio wave incident on the switch when the switch is in the radio wave reflection state is Lr (dB). If the insertion loss of the circulator is Lc (dB) and the coupling degree of the directional coupler is C (dB), the power transmitted to the output terminal through the directional coupler is the semiconductor switch When the input power to 1 is 1, (Equation 1) is obtained.
[0012]
[Expression 1]

[0013]
In addition, the electric power when the radio wave incident on the switch is reflected and guided by the circulator via the detour path to the output terminal via the directional coupler is expressed by (Equation 2).
[0014]
[Expression 2]

[0015]
Therefore, by setting the degree of coupling C of the directional coupler to the value of Equation (3) obtained when Equation (1) and Equation (2) are assumed to be equal, The output level in the route can be kept constant.
[0016]
[Equation 3]

[0017]
According to a second aspect of the present invention, the length of the phase line is set to an arbitrary length, and a part of the carrier wave input from the first terminal of the circulator and output from the second terminal is the switch. And the transmission loss of the BPSK modulator is measured in a state where the switch is set so that the remaining part of the carrier power is reflected by the switch, and among the null points obtained as a result, The wavelength at the null point lower than the desired frequency and closest to the desired frequency is λa, the wavelength at the null point higher than the desired frequency and closest to the desired frequency is λb, and the wavelength at the desired frequency Is λ0, the length of the phase line is shortened by λb (λa−λ0) / (λa−λb) from the arbitrary length set when measuring the transmission loss of the BPSK modulator.
[0018]
In this configuration, by setting the switch so that the power transmitted through the switch and the power reflected by the switch exist at the same time, the path of the radio wave transmitted through the switch and guided to the output end through the transmission line and the directional coupler And at the frequency where the difference in the path of the radio wave reflected by the switch and passed through the detour path by the circulator and guided to the output end through the directional coupler is an odd multiple of half wavelength, the phase of the radio wave propagating through both paths is Because of the 180 ° difference, the output level decreases sharply with respect to other frequencies. When the path difference between the two paths is Δl and m is an arbitrary integer, (Expression 4) and (Expression 5) are obtained.
[0019]
[Expression 4]

[0020]
[Equation 5]

[0021]
Also, if the length of the detour path to be shortened to obtain a phase difference of 180 ° at a desired frequency is α, the relational expression (Equation 6) holds.
[0022]
[Formula 6]

[0023]
Therefore, α is obtained as (Equation 7) from the above (Equation 4), (Equation 5), and (Equation 6).
[0024]
[Expression 7]

[0025]
Therefore, the detour path length to be shortened can be easily calculated from the frequency characteristic of the transmission loss of the BPSK modulator to obtain a phase difference of 180 ° at a desired frequency.
[0026]
Embodiments of the present invention will be described below. FIG. 1 is a perspective view of an NRD guide BPSK modulator according to an embodiment of the present invention, and FIG. 2 is a perspective view of a directional coupler used in the NRD guide BPSK modulator. In FIG. 1, 12 and 12 'are conductor plates. Reference numerals 1 and 1 ′ denote ferrite disks, and reference numeral 2 denotes a dielectric tube that supports two ferrite disks 1 and 1 ′. Reference numerals 3a, 3b, and 3c denote mode suppressors for suppressing unwanted modes. Reference numerals 4 and 4 'denote ferrite disks 1 and 1', and magnets arranged on the concentric axis with the dielectric tube 2, respectively. A circulator is configured together with the dielectric tube 2 and the mode suppressors 3a, 3b, and 3c.
[0027]
5 is an input line connected to one end of the circulator, and 6 is an output line. A mount 10 loaded with semiconductor elements functions as a semiconductor switch. 9 is a high dielectric constant thin plate, and 8 is a matching line. Reference numeral 7 denotes an air gap provided between the mode suppressor 3b and the matching line 8. When the baseband signal is applied so that the radio wave is transmitted through the mount 10 together with the length of the high dielectric constant thin plate 9 and the matching line 8, The reflected power at the mount 10 is suppressed. Reference numeral 11 denotes a baseband signal input terminal for applying a bias voltage to a semiconductor such as a PIN diode mounted on the mount.
[0028]
13 and 13 'are phase difference adjusting lines, 14 is a 180 ° bend, and 15 is a 75 ° bend. Reference numeral 16 denotes an anti-reflection terminator connected to the 75 ° bend 15. Reference numeral 18 denotes an output terminal of the BPSK modulator. The output line 6 and the 75 ° bend 15 form a directional coupler at the closest part of both lines, and the phase difference adjusting line 13, the 180 ° bend 14, the phase difference adjusting lines 13 ′ and 75 °. A detour is formed by the bend 15.
[0029]
In FIG. 2, reference numeral 18 denotes a part of the output line 6, which is an input terminal of the directional coupler connected to the mount 10, and 19 denotes an input terminal of the directional coupler which is a part of the 75 ° bend 15, Reference numeral 20 denotes an output end of a directional coupler connected to the output end 17 as a part of the output line 12, and reference numeral 21 denotes an output end of the directional coupler connected to the antireflection terminator 16 as a part of the 75 ° bend 15. It is.
[0030]
The operation of the NRD guide BPSK modulator configured as described above will be described. Radio waves are incident on the modulator from the input line 5. The incident radio wave is loaded with a semiconductor such as a PIN diode by a circulator composed of ferrite disks 1 and 1 ′, a dielectric tube 2, mode suppressors 3a, 3b and 3c, and magnets 4 and 4 ′. The light is guided to a mount 10 that functions as a switch for switching between transmission and reflection of incident radio waves. The baseband signal applied to the semiconductor element loaded on the mount 10 from the baseband signal input terminal 11 switches between transmission and reflection of radio waves incident on the mount 10. To reach the output line 6. When radio waves are reflected by the mount 10, the detour path is transmitted by the circulator and reaches the output line 6 via the directional coupler.
[0031]
Here, the difference between the path of the radio wave that passes through the mount 10 and reaches the output end 17 in advance and the path of the radio wave that is reflected by the mount 10 and reaches the output end 17 through the detour path by the circulator is an odd multiple of a half wavelength. By setting the phase difference adjusting lines 13 and 13 ′ in this way, the phase of the output wave can be switched by 180 ° with the baseband signal applied to the semiconductor element loaded on the mount 10, and BPSK modulation can be performed. Further, from the transmission loss Lt (dB) of the mount 10 and the degree of coupling C (dB) of the directional coupler when a bias voltage is applied so that the radio wave is transmitted through the mount 10, the radio wave incident on the mount 10 is 10, after passing through 10, the magnitude of power passing from the input end 18 of the directional coupler to the output end 17 through the output end 20 of the directional coupler is set so that the magnitude of power incident on the mount 10 is 1. In this case, it can be expressed by (Equation 8).
[0032]
[Equation 8]

[0033]
Further, when the baseband signal is set so that the radio wave is reflected by the mount 10, the radio wave incident on the mount 10 is reflected by the mount 10 from the reflection loss Lr (dB) of the mount 10 and the insertion loss Lc (dB) of the circulator. The magnitude of the power that is reflected and reaches the output end 17 via the phase difference adjusting line 13, 180 ° bend 14, phase difference adjusting line 13 ′, and directional coupler is determined by the magnitude of the power incident on the mount 10. When it is 1, it can be expressed by (Equation 9).
[0034]
[Equation 9]

[0035]
Here, by setting the coupling degree C of the directional coupler to the value of the equation (10) obtained by assuming that the two values are equal, the fluctuation of the output at the output terminal 17 when the two paths are switched is set. Can be eliminated.
[0036]
[Expression 10]

[0037]
Here, the degree of coupling of the directional coupler means that the radio wave incident from the input end 18 of the directional coupler is PIN and the power output from the output end 21 of the directional coupler is Pout, or the directionality. When the power incident from the input terminal 19 of the coupler is PIN and the power output from the output terminal 20 of the directional coupler is Pout, the value defined by the equation (11) is shown.
[0038]
[Expression 11]

[0039]
Next, a method for determining the length of the phase difference adjusting line will be described with reference to FIG. 3 showing frequency characteristics of transmission loss of the BPSK modulator. FIG. 3 is a frequency characteristic diagram of transmission loss of the NRD guide BPSK modulator according to the embodiment of the present invention. In the BPSK modulator shown in FIG. 1, the baseband applied to the semiconductor element loaded on the mount 10 so that the power transmitted through the mount 10 and the power reflected by the mount 10 exist simultaneously. When the signal is set and the frequency characteristics of the transmission loss are measured, the radio wave passing through the mount 10 and reaching the output end 17 is reflected by the mount 7 and the phase difference adjusting line 13, 180 ° bend 14, phase difference adjusting. Null points 27, 28 and 29 at frequencies 22, 23, 24 and 25 at which the path difference of the radio wave reaching the output end 17 via the line 13 ′, 75 ° bend 15 and the directional coupler is an odd multiple of a half wavelength. , 30 is generated. Assuming that the path difference is Δl, the wavelength at the frequency 23 is λa, the wavelength at the frequency 24 is λb, and m is an arbitrary integer, the relationship of Expressions (12) and (13) is established.
[0040]
[Expression 12]

[0041]
[Formula 13]

[0042]
Further, in order to generate a null point at the desired frequency 26, when the transmission path difference to be shortened is α and the wavelength at the desired frequency 26 is λ0, (Equation 14) is obtained.
[0043]
[Expression 14]

[0044]
Α can be obtained as (Equation 15) from the equations (Equation 12), (Equation 13), and (Equation 14).
[0045]
[Expression 15]

[0046]
The phase difference between the two paths at the desired frequency 26 is set to 180 ° by shortening the phase difference lines 14 and 14 ′ whose length is tentatively determined by the length of α in the equation (15). The phase of the output wave can be switched by 180 ° with a baseband signal to the semiconductor element loaded on the mount 10. In addition, although the calculation method of the length which should be shortened of the phase difference adjustment lines 13 and 13 'defined provisionally was demonstrated here, the transmission path difference length which should be extended is set to (beta) instead of (Formula 14) (Formula 14). The length of the phase difference adjusting lines 13 and 13 ′ may be increased by the length of the equation (17) obtained by using the equation (16).
[0047]
[Expression 16]

[0048]
[Expression 17]

[0049]
As described above, in this embodiment, both the radio wave incident on and transmitted through the mount 10 and the radio wave reflected by the mount 10 are guided to the output end 17 via the directional coupler. By setting the degree of coupling as (Equation 18), the output level when the two paths are switched can be kept constant.
[0050]
[Expression 18]

[0051]
In addition, the phase difference adjusting lines 13 and 13 ′ whose length is provisionally determined are desired to obtain a phase difference of 180 ° from the wavelength at the null points 28 and 29 obtained from the frequency characteristics of the transmission loss of the modulator. From the wavelength of the frequency 26, the length of the phase difference adjusting lines 13, 13 ′ to be shortened can be obtained as (Equation 19), and it should be shortened only by measuring the frequency characteristic of the transmission loss of the BPSK modulator once. The lengths of the phase difference adjusting lines 13 and 13 ′ can be calculated.
[0052]
[Equation 19]

[0053]
【The invention's effect】
According to the present invention described above, fluctuations in the output level when the phase of the output wave is switched by 180 ° can be eliminated. Further, the adjustment of the path difference between the two transmission paths can be easily calculated from the measurement data of the frequency characteristics of the transmission loss of the BPSK modulator.
[Brief description of the drawings]
FIG. 1 is a perspective view of an NRD guide BPSK modulator according to an embodiment of the present invention. FIG. 2 is a perspective view of a directional coupler used in the NRD guide BPSK modulator according to an embodiment of the present invention. FIG. 3 is a frequency characteristic diagram of transmission loss of an NRD guide BPSK modulator according to an embodiment of the present invention. FIG. 4 is a block diagram of a conventional BPSK modulator.
1, 1 'Ferrite disk 2 Dielectric tubes 3a, 3b, 3c Mode suppressor 4, 4' Magnet 5 Input line 6 Output line 7 Air gap 8 Matching line 9 High dielectric constant thin plate 10 Mount 11 Baseband signal input terminals 12, 12 ' Conductor plates 13 and 13 'Phase difference adjusting line 14 180 ° bend 15 75 ° bend 16 Non-reflection terminator 17 Output end 18 and 19 Directional coupler input end 20 and 21 Directional coupler output end 22 to 25 Frequency 26 Desired frequency 27-30 Null point 31 Carrier input terminal 32 Circulator 33 High pass filter 34 Low pass filter 35 PIN diode 36 Reflector

Claims (2)

A circulator having three terminals, a first terminal, a second terminal, and a third terminal, in which the rotation direction is the order of the first terminal, the second terminal, and the third terminal, and one end An input line connected to the first terminal of the circulator and two terminals, and one terminal is connected to the second terminal of the circulator, and transmits and reflects radio waves incident by a baseband signal. A switch for switching, a phase line having one end connected to the third terminal of the circulator, a first line, and a second line, and one end of the first line being another terminal of the switch A directional coupler in which one end of the second line is connected to the other end of the phase line, and connected to the first line of the directional coupler or the other end of the second line. Non-reflective terminator and the non-reflective terminator The circulator is constituted by an output line connected to the other end of the first line or the second line of the directional coupler not connected to the circulator, and by inputting a baseband signal to the switch. The transmission path of the carrier wave input from the first terminal is switched by the switch, and the coupling degree C of the directional coupler is set to L t (dB ) when the switch is in a radio wave transmission state. ) A BPSK modulator characterized in that the reflection loss in the reflection state is set to L r (dB), and the circulator insertion loss is set to L c (dB) as shown in the following equation .

The length of the phase line is set to an arbitrary length, a part of the carrier wave input from the first terminal of the circulator and output from the second terminal passes through the switch, and the remainder of the carrier power The transmission loss of the BPSK modulator is measured in a state in which the switch is set so that a part of the reflection is reflected by the switch, and among the null points obtained as a result, it is lower than the desired frequency and is most desired. If the wavelength at the null point close to the frequency is λa, the wavelength at the null point higher than the desired frequency and closest to the desired frequency is λb, and the wavelength at the desired frequency is λ0, then the phase line 2. The BPSK modulator according to claim 1, wherein the length is shortened by [lambda] b ([lambda] a- [lambda] 0) / ([lambda] a- [lambda] b) from an arbitrary length set when measuring the transmission loss of the BPSK modulator.

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