JP2008215952A - Radar receiver - Google Patents

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JP2008215952A
JP2008215952A JP2007051814A JP2007051814A JP2008215952A JP 2008215952 A JP2008215952 A JP 2008215952A JP 2007051814 A JP2007051814 A JP 2007051814A JP 2007051814 A JP2007051814 A JP 2007051814A JP 2008215952 A JP2008215952 A JP 2008215952A
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signal
mixer
gain
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JP4854543B2 (en
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Osamu Sato
治 佐藤
Masaya Sawayanagi
雅哉 沢柳
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Japan Radio Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent reception signals from sneaking in and to enter a large signal route, from a small signal route, at a low cost using a simple configuration, in order to improve NF characteristics, in addition to improving the sensitivity of reception and widening the dynamic range. <P>SOLUTION: A signal S1 on the small signal route branched by a directional coupler 205 is input to a mixer 202 via a low-noise amplifier 201, and a low-gain signal S2 on the large signal route is input to a mixer 207, and then intermediate frequency signals are taken out of mixed signals, respectively. A local oscillating signal, generated by a local oscillator 203, is distributed and applied to the mixers 202, 207 by using a distributor 206, such that applying on the mixer 202 side is carried out with zero gain, by transmitting the signal through a series circuit comprising an attenuator 209 and an amplifier 210. The gain of the low-noise amplifier 201 is offset by the negative gains of the attenuator 206 and the amplifier 210 in a direction from the mixer 202 to the distributor 206, thereby preventing the signal S1 on the small signal route from turning so as to enter the large signal route side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、良好な感度特性と広いダイナミックレンジを同時に実現したレーダ受信機に関するものである。   The present invention relates to a radar receiver that simultaneously realizes good sensitivity characteristics and a wide dynamic range.

一般的なレーダ受信機は、図２に示すように、レーダ送信機から送信されターゲットで反射されアンテナ１００で受信されたレーダ波を増幅すると共にスーパーヘテロダイン方式により中間周波数信号を取り出すフロントエンド部２００Ａ、フロントエンド部２００Ａで得られた中間周波数信号を増幅するＩＦ部３００Ａ、中間周波数信号から映像信号を作成する指示部４００、および映像信号を表示する表示部５００を備える。   As shown in FIG. 2, a general radar receiver amplifies a radar wave transmitted from a radar transmitter, reflected by a target and received by an antenna 100, and extracts an intermediate frequency signal by a superheterodyne method. IF section 300A for amplifying the intermediate frequency signal obtained by front end section 200A, instruction section 400 for creating a video signal from the intermediate frequency signal, and display section 500 for displaying the video signal.

フロントエンド部２００Ａでは、受信レーダ波を低雑音増幅器２０１Ａで増幅して、ミキサ２０２で局部発振器２０３から出力する局部発振信号とミキシングすることによりビート周波数成分を取り出し、ローパスフィルタ２０４によりその差分周波数を中間周波信号として取り出す。ＩＦ部３００Ａでは、中間周波信号を前置増幅器３０１Ａで増幅し対数増幅・検波部３０２に入力して増幅検波することにより、図３に示すような特性の検波信号を取り出す。この検波信号は、あるダイナミックレンジ領域では入力信号レベルに比例するが、それ以下では出力無し、それ以上では飽和した一定値となる。   In the front end unit 200A, the received radar wave is amplified by the low noise amplifier 201A, and mixed with the local oscillation signal output from the local oscillator 203 by the mixer 202, and the beat frequency component is extracted. Extracted as an intermediate frequency signal. The IF unit 300A amplifies the intermediate frequency signal by the preamplifier 301A, inputs it to the logarithmic amplification / detection unit 302 and amplifies and detects it, thereby extracting a detection signal having the characteristics shown in FIG. This detection signal is proportional to the input signal level in a certain dynamic range region, but there is no output below it, and a saturated constant value above it.

ところで、このようなレーダ受信機では、遠方のターゲットでの反射波と近くのターゲットでの反射波では、その受信レベルに格段の相違があるので、ミキサ２０２の前段に低雑音増幅器２０１Ａを挿入して受信感度の向上を図っているが、その低雑音増幅器２０１Ａを単純に多段化すると、飽和レベルが低下してしまうため、ダイナミックレンジが狭くなる問題があった。そこで、上記のように、低雑音増幅器２０１Ａは１段構成としてある利得に抑えておき、ＩＦ部３００Ａにおいて前置増幅器３０１Ａを多段構成として、ここで必要な利得に増幅してから対数増幅・検波部３０２に入力させていたが、十分なダイナミックレンジを得ることは困難であった。   By the way, in such a radar receiver, there is a great difference in reception level between a reflected wave at a far target and a reflected wave at a nearby target. Therefore, a low noise amplifier 201A is inserted before the mixer 202. However, if the low-noise amplifier 201A is simply multistaged, the saturation level is lowered, and the dynamic range becomes narrow. Therefore, as described above, the low-noise amplifier 201A has a single-stage configuration with a certain gain, and the IF unit 300A has a multi-stage preamplifier 301A to amplify to a necessary gain and logarithmic amplification / detection. However, it is difficult to obtain a sufficient dynamic range.

そこで、本発明者は、フロントエンド部２００Ａを、小信号ルートと大信号ルートに分岐し、小信号ルートでは低レベル信号の受信感度を向上させ、大信号ルートではダイナミックレンジの拡大を図って、感度向上とダイナミックレンジ拡大の両者を満足できるように改善したレーダ受信機を提案した（特許文献１参照）。   Therefore, the present inventor branches the front end unit 200A into a small signal route and a large signal route, improves the reception sensitivity of the low level signal in the small signal route, and expands the dynamic range in the large signal route. A radar receiver improved to satisfy both sensitivity enhancement and dynamic range expansion has been proposed (see Patent Document 1).

このレーダ受信機は、図４に示すように、フロントエンド部２００Ｂにおいて、アンテナ１００で受信したレーダ受信信号を、方向結合器２０５により、減衰量がほとんど無い信号Ｓ１（小信号ルート信号）と、大幅に減衰（例えば−２０ｄＢ）させた信号Ｓ２（大信号ルート信号）に分岐する。そして、信号Ｓ１は、低雑音増幅器２０１で増幅し、ミキサ２０２において、局部発振器２０３から出力する局部発振信号を分配器２０６で分配した信号でミキシングしてビート信号を発生させ、このビート信号の差分周波側信号をローパスフィルタ２０４で取り出して中間周波数信号ＩＦ１とする。一方、信号Ｓ２は、ミキサ２０７において、局部発振器２０３から出力する局部発振信号を分配器２０６で分配した信号でミキシングしてビート信号を発生させ、このビート信号の差分周波側信号をローパスフィルタ２０８で取り出して中間周波数信号ＩＦ２とする。そして、小信号ルートの中間周波信号ＩＦ１は、２段構成の前置増幅器３０１Ａで大きな利得で十分増幅し対数増幅・検波部３０２で増幅検波して加算部３０３に入力させる。また、大信号ルートの中間周波数信号ＩＦ２は、利得が絞られているので、レベル調整・検波部３０４で広いダイナミックレンジをもってレベル調整するとともに検波して加算部３０３に入力させる。   As shown in FIG. 4, in this radar receiver, a radar reception signal received by the antenna 100 at the front end unit 200B is converted into a signal S1 (small signal route signal) having almost no attenuation by the direction coupler 205, and The signal branches to a signal S2 (large signal route signal) that has been greatly attenuated (for example, −20 dB). The signal S1 is amplified by the low-noise amplifier 201, and the mixer 202 mixes the local oscillation signal output from the local oscillator 203 with the signal distributed by the distributor 206 to generate a beat signal. The frequency side signal is taken out by the low-pass filter 204 and used as the intermediate frequency signal IF1. On the other hand, the signal S 2 is mixed in the mixer 207 with the signal obtained by distributing the local oscillation signal output from the local oscillator 203 by the distributor 206 to generate a beat signal, and the difference frequency side signal of this beat signal is generated by the low-pass filter 208. This is taken out as an intermediate frequency signal IF2. Then, the intermediate frequency signal IF1 of the small signal route is sufficiently amplified with a large gain by the two-stage preamplifier 301A, amplified and detected by the logarithmic amplification / detection unit 302, and input to the addition unit 303. Further, since the intermediate frequency signal IF2 of the large signal route has a narrowed gain, the level adjustment / detection unit 304 performs level adjustment with a wide dynamic range, and detects and inputs it to the addition unit 303.

このように、小信号ルートでは信号Ｓ１を飽和レベルは考慮せずに高い利得で増幅し、大信号ルートでは信号Ｓ２を利得よりも飽和レベルを高くして増幅し、これらを加算部３０３で加算することにより、感度向上とダイナミックレンジ拡大の両者を満足した検波信号を出力することができる。   Thus, in the small signal route, the signal S1 is amplified with a high gain without considering the saturation level, and in the large signal route, the signal S2 is amplified with the saturation level higher than the gain, and these are added by the adder 303. By doing so, it is possible to output a detection signal that satisfies both sensitivity improvement and dynamic range expansion.

以上のように、大信号ルートでダイナミックレンジ拡大を図れば、小信号ルートではダイナミックレンジ拡大については考慮する必要がなく、飽和レベルは低くても構わないことになる。つまり、より利得増大を図ることができる。ここで、ミキサ２０２では、６〜１０ｄＢの損失が発生するので、その後段の前置増幅器３０１Ａによる利得の一部をミキサ２０２の前段で確保できるようにすると、この小信号ルートの飽和レベルは１０〜２０ｄＢ程度低下し、ダイナミックレンジが狭くなるが、ＮＦ（雑音指数）特性を従来の４〜６ｄＢから２〜３ｄＢに改善することが可能となる。   As described above, if the dynamic range is expanded in the large signal route, it is not necessary to consider the dynamic range expansion in the small signal route, and the saturation level may be low. That is, the gain can be further increased. Here, since a loss of 6 to 10 dB occurs in the mixer 202, if a part of the gain by the preamplifier 301A in the subsequent stage can be secured in the front stage of the mixer 202, the saturation level of this small signal route is 10%. Although the dynamic range is reduced by about -20 dB, the NF (noise figure) characteristic can be improved from the conventional 4-6 dB to 2-3 dB.

そこで、これを実現するために、図５に示すように、フロントエンド部２００Ｃにおいて、図４に示した１段構成の低雑音増幅器２０１Ａに代えて、２段構成の低雑音増幅器２０１を使用し、利得増大を図ることが好ましい。これにより、低ＮＦ、高利得、広ダイナミックレンジのレーダ受信機を実現できる。
特開２０００−１３７０７１号公報 In order to realize this, as shown in FIG. 5, in the front end unit 200C, a low noise amplifier 201 having a two-stage configuration is used instead of the low noise amplifier 201A having a single stage configuration shown in FIG. It is preferable to increase the gain. Thereby, a radar receiver having a low NF, a high gain, and a wide dynamic range can be realized.
Japanese Patent Laid-Open No. 2000-137071

ところが、このようにすると、小信号ルートのミキサ２０２に入力する信号Ｓ１が極めて大きな大レベルの信号となるのに対して、大信号ルートのミキサ２０７に入力する信号Ｓ２は小レベルの信号となり、ミキサ２０２，２０７の入力側での信号Ｓ１，Ｓ２の利得差Ｇｓが大きくなる。例えば、方向性結合器２０６の小信号ルート側での利得をＧ１（例えば、−０．０４ｄＢ）、大信号ルート側での利得をＧ２（例えば、−２０ｄＢ）、低雑音増幅器２０１での利得をＧ３（例えば、＋３０ｄＢ）とすると、その利得差Ｇｓ１は
Ｇｓ１＝Ｇ１＋Ｇ３−Ｇ２
＝−０．０４＋３０−（−２０）
≒５０ｄＢ
と大きくなる。これに対して、分配器２０６のアイソレーションは、せいぜい２０〜３０ｄＢであるため、小信号ルートの信号Ｓ１が、ミキサ２０２→分配器２０６の経路で、そのミキサ２０７に回り込み、大信号ルートのダイナミックレンジ拡大を阻害する恐れがある。 However, in this case, the signal S1 input to the mixer 202 of the small signal route becomes a very large large level signal, whereas the signal S2 input to the mixer 207 of the large signal route becomes a small level signal. The gain difference Gs between the signals S1 and S2 on the input side of the mixers 202 and 207 increases. For example, the gain on the small signal route side of the directional coupler 206 is G1 (for example, −0.04 dB), the gain on the large signal route side is G2 (for example, −20 dB), and the gain in the low noise amplifier 201 is If G3 (for example, +30 dB), the gain difference Gs1 is Gs1 = G1 + G3-G2.
= −0.04 + 30 − (− 20)
≒ 50dB
And get bigger. On the other hand, since the isolation of the divider 206 is 20 to 30 dB at most, the signal S1 of the small signal route wraps around the mixer 207 through the route of the mixer 202 → the divider 206, and the dynamic of the large signal route. May hinder range expansion.

そこで、これを防止するには、ミキサ２０２と分配器２０６の間にフィルタを挿入して、小信号ルートの信号Ｓ１が分配器２０６側に回り込むことを阻止する対策が考えられるが、受信信号が例えば３０５０ＭＨｚであるのに対して、局部発振器２３の発振周波数は例えば３１１０ＭＨｚ程度と極めて近い周波数であり、また、レーダ送信機のマグネトロンの発振周波数のバラツキ、温度、劣化等による受信周波数変動もあるため、そのフィルタで受信信号Ｓ１のみを阻止することは事実上困難であった。また、アイソレータをミキサ２０２と分配器２０６の間に挿入することも考えられるが、コスト増大を招く問題があった。   Therefore, in order to prevent this, a measure can be considered in which a filter is inserted between the mixer 202 and the distributor 206 to prevent the signal S1 of the small signal route from flowing around to the distributor 206 side. For example, while the frequency is 3050 MHz, the oscillation frequency of the local oscillator 23 is very close to, for example, about 3110 MHz, and the reception frequency fluctuates due to variations in the oscillation frequency of the magnetron of the radar transmitter, temperature, deterioration, and the like. It is practically difficult to block only the received signal S1 with the filter. Although it is conceivable to insert an isolator between the mixer 202 and the distributor 206, there is a problem of increasing the cost.

本発明の目的は、簡単な構成で低コストで、小信号ルートから大信号ルートへの受信信号の回り込みを効果的に防止し、受信感度増大とダイナミックレンジ拡大に加えてＮＦ特性の向上を図ったレーダ受信機を提供することである。   The object of the present invention is to effectively prevent the reception signal from wrapping around from the small signal route to the large signal route with a simple configuration and at low cost, and to improve the NF characteristics in addition to the increase in reception sensitivity and dynamic range. A radar receiver is provided.

上記目的を達成するために、請求項１にかかる発明は、受信信号をほぼ減衰無しで小信号ルート側に出力すると共に、前記受信信号を所定の減衰を与えて大信号ルート側に出力する第１の信号分岐部と、該第１の信号分岐部の前記小信号ルート側から出力する信号を増幅する第１の増幅器と、該第１の増幅器から出力する信号を局部発振信号とミキシングする第１のミキサと、前記第１の信号分岐部の前記大信号ルート側から出力する信号を前記局部発振信号とミキシングする第２のミキサと、前記局部発振信号を生成する局部発振器からの発振信号を前記第１および第２のミキサに分配する第２の信号分岐部とを備えたフロントエンド部を有するレーダ受信機において、前記第２の信号分岐部と前記第１のミキサとの間に、減衰器と、前記第２の信号分岐部側から前記第１のミキサに向けて正の利得を持ち前記第１のミキサ側から前記第２の信号分岐部側に向けて負の利得をもつ第２の増幅器とを直列接続したことを特徴とする。
請求項２にかかる発明は、請求項１に記載のレーダ受信機において、前記減衰器の負の利得と前記第２の増幅器の前記負の利得との合成利得を、前記第１の増幅器の正の利得に対応させたことを特徴とする。
請求項３にかかる発明は、請求項１に記載のレーダ受信機において、前記減衰器の負の利得を、前記第２の増幅器の前記正の利得に対応させたことを特徴とする。 In order to achieve the above object, the invention according to claim 1 outputs the received signal to the small signal route side with almost no attenuation, and outputs the received signal to the large signal route side with a predetermined attenuation. 1 signal branching unit, a first amplifier for amplifying a signal output from the small signal route side of the first signal branching unit, and a signal output from the first amplifier for mixing with a local oscillation signal 1 mixer, a second mixer that mixes a signal output from the large signal route side of the first signal branching unit with the local oscillation signal, and an oscillation signal from a local oscillator that generates the local oscillation signal In a radar receiver having a front-end unit with a second signal branching unit that distributes to the first and second mixers, an attenuation is provided between the second signal branching unit and the first mixer. And the vessel In series, a second amplifier having a positive gain from the second signal branch side toward the first mixer and a negative gain from the first mixer side toward the second signal branch side. It is connected.
According to a second aspect of the present invention, in the radar receiver according to the first aspect, a combined gain of the negative gain of the attenuator and the negative gain of the second amplifier is a positive gain of the first amplifier. It corresponds to the gain of.
According to a third aspect of the present invention, in the radar receiver according to the first aspect, the negative gain of the attenuator is made to correspond to the positive gain of the second amplifier.

本発明によれば、フロントエンド部の小信号ルート側の第１のミキサと第２の信号分岐部との間に、減衰器と第２の増幅器を直列接続し、第１のミキサから第２の信号分岐部方向には所定の減衰量を実現させ、第２の信号分岐部から第１のミキサ方向には減衰無しを実現させることができるので、低コストで小信号ルートから大信号ルートへの信号回り込みを回避することが可能となる。このため、小信号ルートの第１の増幅器に利得の高い低雑音増幅器を使用可能となり、受信感度増大とダイナミックレンジ拡大に加えて、ＮＦ特性を向上させることが可能となる。   According to the present invention, the attenuator and the second amplifier are connected in series between the first mixer on the small signal route side of the front end unit and the second signal branching unit, and the second mixer is connected to the second mixer. From the small signal route to the large signal route at low cost, it is possible to realize a predetermined attenuation amount in the direction of the signal branching portion and no attenuation in the direction from the second signal branching portion to the first mixer. It is possible to avoid the signal wraparound. For this reason, a low-noise amplifier having a high gain can be used as the first amplifier of the small signal route, and it is possible to improve the NF characteristic in addition to the increase in reception sensitivity and dynamic range.

図１は本発明の１つの実施例のレーダ受信機のフロントエンド部２００の構成を示すブロック図である。２０１は２段構成の高利得の低雑音増幅器（第１の増幅器）、２０５は方向性結合器（第１の信号分岐部）、２０２は第１のミキサ、２０７は第２のミキサ、２０３は局部発振器、２０４，２０８はローパスフィルタである。このような図４のフロントエンド部２００Ｂの構成に加えて、本実施例では、減衰器２０９と増幅器（第２の増幅器）２１０を、ミキサ２０２と分配器２０６の間に直列に挿入している。   FIG. 1 is a block diagram showing a configuration of a front end unit 200 of a radar receiver according to one embodiment of the present invention. 201 is a two-stage high gain low noise amplifier (first amplifier), 205 is a directional coupler (first signal branching unit), 202 is a first mixer, 207 is a second mixer, and 203 is The local oscillators 204 and 208 are low pass filters. In addition to the configuration of the front end unit 200B of FIG. 4, in this embodiment, an attenuator 209 and an amplifier (second amplifier) 210 are inserted in series between the mixer 202 and the distributor 206. .

減衰器２０６は入力側と出力側の間において、入力側→出力側の経路の信号、出力側→入力側の経路の信号のいずれについても、同じ減衰量Ｇ４（例えば、−１０ｄＢ）を達成する。これに対し、増幅器２１０は入力側と出力側の間において、入力側→出力側の経路の信号については所定の利得Ｇ５（例えば、＋１０ｄＢ）を実現できるが、出力側→入力側の経路の信号については減衰量Ｇ６（例えば、−２０ｄＢ）となる。   The attenuator 206 achieves the same attenuation G4 (for example, −10 dB) for both the input side → output side path signal and the output side → input side path signal between the input side and the output side. . On the other hand, the amplifier 210 can realize a predetermined gain G5 (for example, +10 dB) between the input side and the output side between the input side and the output side, but the signal on the output side → the input side path. Is an attenuation G6 (for example, -20 dB).

したがって、小信号ルートからミキサ２０２→分配器２０６方向の利得Ｇｓ２は、
Ｇｓ２＝Ｇ４＋Ｇ６
＝−１０−２０
＝−３０ｄＢ
となり、低雑音増幅器２０１の利得Ｇ３を打ち消す利得となる。 Therefore, the gain Gs2 from the small signal route to the mixer 202 → distributor 206 is
Gs2 = G4 + G6
= -10-20
= -30dB
Thus, the gain cancels the gain G3 of the low noise amplifier 201.

よって、ミキサ２０７への回り込み信号の利得Ｇｓ３は、上記例を適用すれば、
Ｇｓ３＝Ｇｓ１＋Ｇｓ２
＝５０−３０
＝２０ｄＢ
に低減させることができる。この利得Ｇｓ３は、分配器２０６のアイソレーション（２０〜３０ｄＢ）によって打ち消すことができ、結局、小信号ルートからミキサ２０２→ミキサ２０７への回り込み信号を打ち消すことが可能となる。 Therefore, if the above example is applied to the gain Gs3 of the sneak signal to the mixer 207,
Gs3 = Gs1 + Gs2
= 50-30
= 20dB
Can be reduced. This gain Gs3 can be canceled by the isolation (20 to 30 dB) of the divider 206, and eventually the sneak signal from the small signal route to the mixer 202 → mixer 207 can be canceled.

なお、局部発振器２０３からミキサ２０２に出力する局部発振信号の利得Ｇｒは、
Ｇｒ＝Ｇ６＋Ｇ４
＝＋１０＋（−１０）
＝０ｄＢ
になり、それら減衰器２０９と増幅器２１０の影響を回避することができる。 The gain Gr of the local oscillation signal output from the local oscillator 203 to the mixer 202 is
Gr = G6 + G4
= + 10 + (− 10)
= 0dB
Thus, the influence of the attenuator 209 and the amplifier 210 can be avoided.

以上のように、本実施例のフロントエンド部２００によれば、小信号ルートのミキサ２０２の受信信号と大信号ルートのミキサ２０７の受信信号に大きな利得差が生じていたとしても、ミキサ２０２と分配器２０６の間に挿入した減衰器２０９と増幅器２１０によって、低雑音増幅器２０１の利得分を打ち消すことが可能となり、小信号ルートから大信号ルートへの受信信号の回り込みを防止することができる。よって、小信号ルートに２段構成の低雑音増幅器２０１を接続してフロントエンド部２００での小信号ルートの高利得化を図っても信号回り込みの問題が生じることは無くなり、ＮＦ特性を大きく改善することが可能となる。   As described above, according to the front end unit 200 of the present embodiment, even if there is a large gain difference between the reception signal of the mixer 202 of the small signal route and the reception signal of the mixer 207 of the large signal route, The attenuator 209 and the amplifier 210 inserted between the dividers 206 can cancel the gain of the low noise amplifier 201, and the reception signal from the small signal route to the large signal route can be prevented. Therefore, even if the low-noise amplifier 201 having a two-stage configuration is connected to the small signal route to increase the gain of the small signal route in the front end unit 200, the problem of signal wraparound does not occur, and the NF characteristic is greatly improved. It becomes possible to do.

本発明の実施例のレーダ受信機のフロントエンド部の構成を示すブロック図である。It is a block diagram which shows the structure of the front end part of the radar receiver of the Example of this invention. 従来のレーダ受信機の構成を示すブロック図である。It is a block diagram which shows the structure of the conventional radar receiver. 図２のレーダ受信機のＩＦ部における検波信号の特性図である。FIG. 3 is a characteristic diagram of a detection signal in an IF unit of the radar receiver of FIG. 2. 高利得化と広ダイナミックレンジ化を図った従来のレーダ受信機の構成を示すブロック図である。It is a block diagram which shows the structure of the conventional radar receiver which aimed at high gain and wide dynamic range. 図４のレーダ受信機の更なるＮＦ特性の改善を図ったフロントエンド部の構成を示すブロック図である。FIG. 5 is a block diagram illustrating a configuration of a front end unit that further improves the NF characteristics of the radar receiver of FIG. 4.

符号の説明Explanation of symbols

１００：アンテナ
２００，２００Ａ，２００Ｂ：フロントエンド部、２０１、２０１Ａ：低雑音増幅器、２０２：ミキサ、２０３：局部発振器、２０４：ローパスフィルタ、２０５：方向性結合器、２０６：分配器、２０７：ミキサ、２０８：ローパスフィルタ、２０９：減衰器、２１０：増幅器
３００，３００Ａ，３００Ｂ：ＩＦ部、３０１，３０１Ａ：前置増幅器、３０２：対数増幅・検波部、３０３：加算部、３０４：レベル調整・検波部
４００：指示部
５００：表示部 100: antenna 200, 200A, 200B: front end section, 201, 201A: low noise amplifier, 202: mixer, 203: local oscillator, 204: low pass filter, 205: directional coupler, 206: distributor, 207: mixer 208: Low-pass filter, 209: Attenuator, 210: Amplifier 300, 300A, 300B: IF section, 301, 301A: Preamplifier, 302: Logarithmic amplification / detection section, 303: Addition section, 304: Level adjustment / detection Part 400: Instruction part 500: Display part

Claims (3)

受信信号をほぼ減衰無しで小信号ルート側に出力すると共に、前記受信信号を所定の減衰を与えて大信号ルート側に出力する第１の信号分岐部と、該第１の信号分岐部の前記小信号ルート側から出力する信号を増幅する第１の増幅器と、該第１の増幅器から出力する信号を局部発振信号とミキシングする第１のミキサと、前記第１の信号分岐部の前記大信号ルート側から出力する信号を前記局部発振信号とミキシングする第２のミキサと、前記局部発振信号を生成する局部発振器からの発振信号を前記第１および第２のミキサに分配する第２の信号分岐部とを備えたフロントエンド部を有するレーダ受信機において、
前記第２の信号分岐部と前記第１のミキサとの間に、減衰器と、前記第２の信号分岐部側から前記第１のミキサに向けて正の利得を持ち前記第１のミキサ側から前記第２の信号分岐部側に向けて負の利得をもつ第２の増幅器とを直列接続したことを特徴とするレーダ受信機。 A first signal branching unit that outputs a reception signal to the small signal route side with almost no attenuation, and outputs the reception signal to the large signal route side with a predetermined attenuation, and the first signal branching unit A first amplifier for amplifying a signal output from the small signal route side, a first mixer for mixing a signal output from the first amplifier with a local oscillation signal, and the large signal of the first signal branching unit A second mixer for mixing a signal output from the root side with the local oscillation signal, and a second signal branch for distributing the oscillation signal from the local oscillator for generating the local oscillation signal to the first and second mixers In a radar receiver having a front end portion with a portion,
An attenuator between the second signal branching unit and the first mixer, and having a positive gain from the second signal branching unit side toward the first mixer side, the first mixer side A radar receiver, wherein a second amplifier having a negative gain is connected in series toward the second signal branching portion side. 請求項１に記載のレーダ受信機において、
前記減衰器の負の利得と前記第２の増幅器の前記負の利得との合成利得を、前記第１の増幅器の正の利得に対応させたことを特徴とするレーダ受信機。 The radar receiver according to claim 1, wherein
A radar receiver characterized in that a combined gain of the negative gain of the attenuator and the negative gain of the second amplifier corresponds to the positive gain of the first amplifier. 請求項１に記載のレーダ受信機において、
前記減衰器の負の利得を、前記第２の増幅器の前記正の利得に対応させたことを特徴とするレーダ受信機。 The radar receiver according to claim 1, wherein
A radar receiver, wherein a negative gain of the attenuator is made to correspond to the positive gain of the second amplifier.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013124993A (en) * 2011-12-15 2013-06-24 Furuno Electric Co Ltd Radar receiver and radar system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11174143A (en) * 1997-12-11 1999-07-02 Mitsubishi Electric Corp Method and device for controlling dynamic range
JP2000137071A (en) * 1998-10-30 2000-05-16 Japan Radio Co Ltd Radar device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11174143A (en) * 1997-12-11 1999-07-02 Mitsubishi Electric Corp Method and device for controlling dynamic range
JP2000137071A (en) * 1998-10-30 2000-05-16 Japan Radio Co Ltd Radar device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013124993A (en) * 2011-12-15 2013-06-24 Furuno Electric Co Ltd Radar receiver and radar system

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