JPH084236B2 - Receiving machine - Google Patents
Receiving machineInfo
- Publication number
- JPH084236B2 JPH084236B2 JP62328114A JP32811487A JPH084236B2 JP H084236 B2 JPH084236 B2 JP H084236B2 JP 62328114 A JP62328114 A JP 62328114A JP 32811487 A JP32811487 A JP 32811487A JP H084236 B2 JPH084236 B2 JP H084236B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- frequency
- amplifier
- high frequency
- intermediate frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Superheterodyne Receivers (AREA)
- Noise Elimination (AREA)
- Circuits Of Receivers In General (AREA)
Description
この発明は、妨害信号によって生じる相互変調作用に
基づく受信妨害を防止できる受信機に関する。The present invention relates to a receiver capable of preventing reception interference due to an intermodulation effect caused by an interference signal.
従来の受信機の要部ブロック回路図を第２図に示す。 第２図において、ANT1で受信されたANT入力信号は、
フイルタを備えたANT回路２を経て、AGC制御される高周
波増幅器３で適宜に増幅されて混合器４に与えられる。
混合器４には局部発振器５から局部発振信号が与えら
れ、高周波増幅器３からの信号が局部発振信号と混合さ
れて中間周波信号に変換される。中間周波信号は中間周
波フイルタ６により所定周波数fIFの中間周波信号のみ
が抽出されて、中間周波増幅器７および増幅器８に与え
られて適宜に増幅される。なお、混合器４と局部発振器
５により第一の周波数変換手段が構成されている。 増幅器８によって増幅された中間周波信号は、レベル
検波器９に供給され、レベル検波器９によりその大きさ
に応じた直流信号に変換されてAGC回路10に与えられ、A
GC回路10で適宜なAGC電圧に変換される。このAGC電圧を
与えられて高周波増幅器３の増幅度がAGC制御される。
なお、増幅器８、レベル検波器９、AGC回路10でAGC検出
回路11が構成されている。FIG. 2 shows a block circuit diagram of a main part of a conventional receiver. In Figure 2, the ANT input signal received by ANT1 is
After passing through the ANT circuit 2 equipped with a filter, it is appropriately amplified by the AGC-controlled high frequency amplifier 3 and given to the mixer 4.
A local oscillation signal is applied to the mixer 4 from the local oscillator 5, and the signal from the high frequency amplifier 3 is mixed with the local oscillation signal and converted into an intermediate frequency signal. Only the intermediate frequency signal of the predetermined frequency fIF is extracted by the intermediate frequency filter 6 from the intermediate frequency signal, and the intermediate frequency signal is given to the intermediate frequency amplifier 7 and the amplifier 8 and appropriately amplified. The mixer 4 and the local oscillator 5 constitute a first frequency conversion means. The intermediate frequency signal amplified by the amplifier 8 is supplied to the level detector 9, is converted into a DC signal according to the magnitude thereof by the level detector 9, and is applied to the AGC circuit 10,
It is converted into an appropriate AGC voltage by the GC circuit 10. The amplification degree of the high frequency amplifier 3 is AGC controlled by being supplied with this AGC voltage.
The amplifier 8, the level detector 9, and the AGC circuit 10 constitute an AGC detection circuit 11.
ところで、入力信号中には一般に強度が受信希望信号
よりも大きな妨害信号が含まれている。この妨害信号は
高周波増幅器３にその飽和強度を超えて加わる。そし
て、この妨害信号は中間周波フイルタ６で減衰され、高
周波増幅器３の増幅度は、受信希望信号が適宜な強度に
なるように制御されるために、受信希望信号よりも強度
が大きな妨害信号は混合器４にもその飽和強度を超えて
加わることになる。そこで、妨害信号は高周波増幅器３
または混合器４においてクリップされて歪み、相互変調
信号が発生する。 この相互変調信号の周波数が受信希望信号の周波数と
同じであれば、これを中間周波フイルタ６で阻止できず
混信が生じて受信品質が損なわれる。そのうえ相互変調
信号の強度が受信希望信号の強度よりも大きければ、高
周波増幅器３の増幅度はこの相互変調信号の強度に応じ
て制御される。すなわち高周波増幅器３の増幅度は受信
希望信号の強度に関わらず低減され、中間周波増幅器７
に供給される受信希望信号の強度が低下し、受信感度が
不足するという問題があった。 そこでこの発明の目的は、受信希望信号と同じ周波数
の相互変調信号が発生せず、受信希望信号が適宜な強度
で中間周波増幅器７に供給される受信機を提供すること
にある。By the way, the input signal generally contains an interfering signal whose strength is larger than that of the desired signal to be received. This disturbing signal is applied to the high frequency amplifier 3 in excess of its saturation strength. This interfering signal is attenuated by the intermediate frequency filter 6, and the amplification degree of the high frequency amplifier 3 is controlled so that the desired reception signal has an appropriate strength. The saturation strength will be added to the mixer 4 as well. Therefore, the interfering signal is the high frequency amplifier 3
Alternatively, the signal is clipped and distorted in the mixer 4 to generate an intermodulation signal. If the frequency of this intermodulation signal is the same as the frequency of the desired reception signal, this cannot be blocked by the intermediate frequency filter 6, interference occurs and the reception quality is impaired. Moreover, if the strength of the intermodulation signal is larger than the strength of the desired reception signal, the amplification degree of the high frequency amplifier 3 is controlled according to the strength of the intermodulation signal. That is, the amplification degree of the high frequency amplifier 3 is reduced regardless of the intensity of the desired signal to be received, and the intermediate frequency amplifier 7
There is a problem in that the strength of the desired reception signal supplied to the device decreases and the reception sensitivity becomes insufficient. Therefore, an object of the present invention is to provide a receiver in which an intermodulation signal having the same frequency as the desired reception signal is not generated and the desired reception signal is supplied to the intermediate frequency amplifier 7 with an appropriate intensity.
かかる問題を解決するために、この発明による受信機
は、受信希望信号によりAGC制御される高周波増幅器
と、この高周波増幅器で増幅された信号を局部発振信号
と混合することにより中間周波信号に変換する第一の周
波数変換手段を備えて受信機において、可変減衰手段
と、この可変減衰手段を通過した信号を分配する分配手
段と、この分配された信号を局部発振信号と混合するこ
とにより第二の中間周波信号に変換する第二の周波数変
換手段と、第二の中間周波信号のうち受信希望信号によ
る中間周波信号を除去するIF除去手段と、このIF除去手
段を通過した残余信号を歪ませる歪発生手段と、この歪
発生手段で発生し受信希望信号による中間周波信号と同
じ周波数の相互変調信号を抽出するIM抽出手段と、この
IM抽出手段による抽出信号の強度に応じた減衰度制御電
圧を前記可変減衰手段に与える減衰器駆動回路を備え、
前記高周波増幅器の前段に前記分配手段と前記可変減衰
手段を介装したことを特徴としている。In order to solve such a problem, a receiver according to the present invention converts a high frequency amplifier which is AGC controlled by a desired signal to be received and an intermediate frequency signal by mixing a signal amplified by the high frequency amplifier with a local oscillation signal. In the receiver provided with the first frequency converting means, the variable attenuating means, the distributing means for distributing the signal passing through the variable attenuating means, and the second oscillating signal by mixing the distributed signal with the local oscillation signal. Second frequency converting means for converting to an intermediate frequency signal, IF removing means for removing an intermediate frequency signal of the second intermediate frequency signal due to the desired reception signal, and distortion for distorting the residual signal passing through this IF removing means Generating means, IM extracting means for extracting an intermodulation signal having the same frequency as the intermediate frequency signal generated by the distortion generating means and the desired reception signal, and
An attenuator drive circuit that provides the variable attenuation means with an attenuation control voltage according to the strength of the extracted signal by the IM extraction means,
It is characterized in that the distribution means and the variable attenuation means are provided in a stage preceding the high frequency amplifier.
入力信号は、相互変調検出回路で検出された相互変調
信号、すなわち受信希望信号と同じ周波数の相互変調信
号の強度に応じて可変減衰手段によって減衰された後、
高周波増幅器に入力される。 したがって、受信希望信号と同じ周波数の相互変調信
号を生じるような強度の大きい妨害信号が受信機に入力
されても、妨害信号は可変減衰手段によって適宜な強度
に減衰され、強度が大きいまま高周波増幅器に加わるこ
とがないので、高周波増幅器や混合器において相互変調
信号が生じない。 また、高周波増幅器の増幅器は受信希望信号の強度に
応じて制御され、受信希望信号は高周波増幅器によつて
適宜な強度に増幅される。The input signal is attenuated by the variable attenuator according to the intensity of the intermodulation signal detected by the intermodulation detection circuit, that is, the intermodulation signal having the same frequency as the desired reception signal,
Input to high frequency amplifier. Therefore, even if an interfering signal having a high intensity that produces an intermodulation signal having the same frequency as the desired signal to be received is input to the receiver, the interfering signal is attenuated to an appropriate intensity by the variable attenuator, and the high frequency amplifier keeps the intensity high. Therefore, no intermodulation signal is generated in the high frequency amplifier or mixer. Further, the amplifier of the high frequency amplifier is controlled according to the strength of the desired signal to be received, and the desired signal to be received is amplified by the high frequency amplifier to an appropriate strength.
以下に、第１図を参照してこの発明を説明する。第１
図はこの発明の一実施例による受信機の要部回路ブロッ
ク図である。なお第１図において、第２図に図示した従
来の受信機と同じ回路素子には、同じ符号を付けて重複
する説明を省略する。 この発明による受信機は、ANT入力信号に含まれた妨
害信号によって発生することが予測される相互変調信号
を強制的に発生させて、これを検出するための相互変調
検出回路を備え、高周波増幅器３に入力されるANT入力
信号を、相互変調信号の強度に応じて適宜な強度に減衰
制御するものである。 そこで、ANT回路２と高周波増幅器３の間に、可変減
衰手段である可変減衰器22と、分配器12を順次に介装
し、分配器12の一方の分配出力端に相互変調検出回路13
と減衰器駆動回路21を順次に接続し、減衰器駆動回路21
の出力を可変減衰器22に供給するように構成している。
そして相互変調検出回路13は、高周波増幅器14と、混合
器15と、IF除去フイルタ16と、歪発生増幅器17と、IM抽
出フイルタ18と、増幅器19と、レベル検波器20とから成
っている。 この受信機において、分配器12により分配されたATN
入力信号が相互変調検出回路13に入力され、高周波増幅
器14により増幅された後、混合器15に与えられる。混合
器15には局部発振器５から局部発振信号が与えられ、高
周波増幅器14から与えられた信号が局部発振信号と混合
されて第二の中間周波信号に変換され、IF除去フイルタ
16に与えられる。なお、混合器15と局部発振器５により
第二の周波数変換手段が構成されている。また、IF除去
フイルタ16は例えばFM受信機であれば、所定周波数10.7
MHzの中間周波信号を除去するものであり、セラミック
フイルタ等のバンドエリミネータまたはトラップであ
る。 IF除去フイルタ16で所定周波数fIFの中間周波信号を
除去された残余信号は複数の妨害信号を含んでおり、こ
れを歪発生増幅器17で歪ませることにより、相互変調
（以下、IMと略称する）信号を発生させる。歪発生増幅
器17の出力信号はIM抽出フイルタ18に入力される。IM抽
出フイルタ18は所定周波数fIFの信号を抽出するもので
ある。 したがって歪発生増幅器17の出力信号に所定周波数fI
FのIM信号が存在すれば、そのIM信号はIM抽出フイルタ1
8で抽出され、次の増幅器19で増幅されてレベル検波器2
0において強度電圧が検出される。強度電圧は減衰器駆
動回路21に導かれ、減衰器駆動回路21において強度電圧
に応じた減衰度制御電圧が生成され、これを可変減衰器
22に供給する。可変減衰器22はPINダイオード等の大入
力信号に対しても直線的な減衰特性を示す素子で構成さ
れ、減衰度制御電圧に応じてANT入力信号を減衰させる
ものである。 かかる構成の受信機において、希望信号よりも大きな
強度の妨害信号が入力信号に含まれており、歪発生増幅
器17において所定周波数fIFのIM信号が発生する場合
は、IM抽出フイルタ18でIM信号が抽出され、このIM信号
の強度に応じた減衰度制御電圧により、可変減衰器22が
減衰動作をする。このため入力信号は減衰されて高周波
増幅器３に加わるので、妨害信号によって高周波増幅器
３および混合器４が飽和せず、これらにおいてIM信号が
発生しない。したがって高周波増幅器の増幅度は受信希
望信号の強度に応じて制御され、受信希望信号は高周波
増幅器によつて適宜な強度に増幅される。 一方、希望信号よりも大きな強度の妨害信号が入力信
号に含まれていても、歪発生増幅器17において所定周波
数fIFのIM信号が発生しない場合は、IM抽出フイルタ18
でIM信号が抽出されない。このため可変減衰器22は減衰
動作をせず、ANT入力信号は減衰されずに高周波増幅器
３に加わる。この場合は、高周波増幅器３においてIM信
号が発生したとしても、その周波数は所定周波数fIFと
は異なり、IM信号は中間周波フイルタ６で除去される。
したがって高周波増幅器の増幅度は受信希望信号の強度
に応じて制御され、受信希望信号は高周波増幅器によつ
て適宜な強度に増幅される。 なお、上記の実施例において、第一の周波数交換手段
と第二の周波数交換手段とで局部発振器５を共用してい
るが、第二の周波数交換手段用の局部発振器を別個に用
意しても良く、また分配器12は、可変減衰器22と高周波
増幅器３の間であれば何れの箇所に設けても良い。The present invention will be described below with reference to FIG. First
FIG. 3 is a circuit block diagram of a main part of a receiver according to an embodiment of the present invention. Note that, in FIG. 1, the same circuit elements as those of the conventional receiver shown in FIG. A receiver according to the present invention includes an intermodulation detection circuit for forcibly generating an intermodulation signal that is predicted to be generated by an interfering signal included in an ANT input signal, and detecting the intermodulation signal. The ANT input signal input to 3 is controlled to be attenuated to an appropriate intensity according to the intensity of the intermodulation signal. Therefore, a variable attenuator 22 that is a variable attenuator and a distributor 12 are sequentially interposed between the ANT circuit 2 and the high frequency amplifier 3, and the intermodulation detection circuit 13 is provided at one distribution output end of the distributor 12.
And attenuator drive circuit 21 are connected in sequence, and attenuator drive circuit 21
Is configured to be supplied to the variable attenuator 22.
The intermodulation detection circuit 13 includes a high frequency amplifier 14, a mixer 15, an IF removal filter 16, a distortion generation amplifier 17, an IM extraction filter 18, an amplifier 19, and a level detector 20. In this receiver, the ATN distributed by the distributor 12
The input signal is input to the intermodulation detection circuit 13, amplified by the high frequency amplifier 14, and then given to the mixer 15. A local oscillation signal is supplied from the local oscillator 5 to the mixer 15, the signal supplied from the high frequency amplifier 14 is mixed with the local oscillation signal and converted into a second intermediate frequency signal, and the IF removal filter is supplied.
Given to 16. The mixer 15 and the local oscillator 5 form a second frequency conversion means. If the IF removal filter 16 is, for example, an FM receiver, it has a predetermined frequency of 10.7.
It removes the intermediate frequency signal of MHz and is a band eliminator or trap such as a ceramic filter. The residual signal from which the intermediate frequency signal of the predetermined frequency fIF is removed by the IF removal filter 16 contains a plurality of interfering signals, which are distorted by the distortion generating amplifier 17 to be intermodulated (hereinafter abbreviated as IM). Generate a signal. The output signal of the distortion generating amplifier 17 is input to the IM extraction filter 18. The IM extraction filter 18 extracts a signal of a predetermined frequency fIF. Therefore, the output signal of the distortion generating amplifier 17 has a predetermined frequency fI.
If there is an IM signal of F, that IM signal is the IM extraction filter 1
Level detector 2 extracted at 8 and amplified at the next amplifier 19
At 0 the intensity voltage is detected. The intensity voltage is guided to the attenuator drive circuit 21, and the attenuator drive circuit 21 generates an attenuation degree control voltage according to the intensity voltage.
Supply to 22. The variable attenuator 22 is composed of an element that exhibits a linear attenuation characteristic even for a large input signal such as a PIN diode, and attenuates the ANT input signal according to the attenuation control voltage. In the receiver having such a configuration, when the input signal includes an interfering signal having an intensity higher than the desired signal, and the IM signal of the predetermined frequency fIF is generated in the distortion generating amplifier 17, the IM signal is output by the IM extraction filter 18. The variable attenuator 22 performs an attenuating operation by the attenuation degree control voltage that is extracted and depends on the intensity of the IM signal. Therefore, the input signal is attenuated and added to the high frequency amplifier 3, so that the interference signal does not saturate the high frequency amplifier 3 and the mixer 4, and no IM signal is generated in these. Therefore, the amplification degree of the high frequency amplifier is controlled according to the strength of the desired reception signal, and the desired reception signal is amplified to a proper strength by the high frequency amplifier. On the other hand, if the IM signal of the predetermined frequency fIF is not generated in the distortion generating amplifier 17 even if the input signal includes an interfering signal having an intensity higher than the desired signal, the IM extraction filter 18
IM signal is not extracted in. Therefore, the variable attenuator 22 does not perform the attenuation operation, and the ANT input signal is not attenuated and is added to the high frequency amplifier 3. In this case, even if the IM signal is generated in the high frequency amplifier 3, its frequency is different from the predetermined frequency fIF, and the IM signal is removed by the intermediate frequency filter 6.
Therefore, the amplification degree of the high frequency amplifier is controlled according to the strength of the desired reception signal, and the desired reception signal is amplified to a proper strength by the high frequency amplifier. Although the local oscillator 5 is shared by the first frequency exchanging means and the second frequency exchanging means in the above embodiment, the local oscillator for the second frequency exchanging means may be prepared separately. Also, the distributor 12 may be provided at any place between the variable attenuator 22 and the high frequency amplifier 3.
この発明の受信機によれば、受信希望信号と同じ周波
数の相互変調信号を高周波増幅器３および混合器４にお
いて発生させるような妨害信号が入力させた時、これを
高周波増幅器３の前段で検出し、可変減衰器22で減衰さ
せて高周波増幅器３に入力するようにしたので、高周波
増幅器３および混合器４において、受信希望信号と同じ
周波数の相互変調信号が発生せず、相互変調信号による
受信障害が発生しない。 また、実施例のように、入力信号を中間周波信号に変
換した後に相互変調信号を発生させる構成にしたので、
相互変調検出回路13に可変同調回路を設ける必要がな
く、また、第一および第二の周波数変換手段において局
部発振器５を共用でき、局部発振器５を共用することに
よって回路構成が簡易であり、至って安価に実現できる
という実用的に大きな効果が得られる。 さらに、第一および第二の周波数変換手段において局
部発振器５を共用することによって、第二の周波数変換
手段で検出する相互変調信号の周波数が、第一の周波数
変換手段で発生することが予想される相互変調信号の周
波数と完全に一致し、精度の良い制御ができると云う効
果がえられる。According to the receiver of the present invention, when the interfering signal that causes the intermodulation signal having the same frequency as the reception desired signal to be generated in the high frequency amplifier 3 and the mixer 4, this is detected in the preceding stage of the high frequency amplifier 3. Since it is attenuated by the variable attenuator 22 and input to the high frequency amplifier 3, the high frequency amplifier 3 and the mixer 4 do not generate the intermodulation signal having the same frequency as the desired reception signal, and the reception failure due to the intermodulation signal occurs. Does not occur. Further, as in the embodiment, since the intermodulation signal is generated after converting the input signal into the intermediate frequency signal,
It is not necessary to provide a variable tuning circuit in the intermodulation detection circuit 13, and the local oscillator 5 can be shared by the first and second frequency conversion means. By sharing the local oscillator 5, the circuit configuration is simple, A large practical effect is obtained that can be realized at low cost. Furthermore, by sharing the local oscillator 5 in the first and second frequency converting means, it is expected that the frequency of the intermodulation signal detected by the second frequency converting means will be generated in the first frequency converting means. The frequency of the intermodulation signal is completely matched, and an effect that the control can be performed with high precision can be obtained.
第１図はこの発明の受信機の一実施例の要部回路ブロッ
ク図であり、第２図は従来の受信機の要部回路ブロック
図である。 ３、14……高周波増幅器 ４、15……混合器 ５……局部発振器 ６……中間周波フイルタ ７……中間周波増幅器 ８、19……増幅器 ９、20……レベル検波器 10……AGC回路 11……AGC検出回路 12……分配器 13……相互変調検出回路 16……IF除去フイルタ 17……歪発生増幅器 18……IM抽出フイルタ 21……減衰器駆動回路 22……可変減衰器。FIG. 1 is a circuit block diagram of essential parts of an embodiment of a receiver of the present invention, and FIG. 2 is a circuit block diagram of essential parts of a conventional receiver. 3,14 …… High frequency amplifier 4,15 …… Mixer 5 …… Local oscillator 6 …… Intermediate frequency filter 7 …… Intermediate frequency amplifier 8,19 …… Amplifier 9,20 …… Level detector 10 …… AGC circuit 11 …… AGC detection circuit 12 …… Distributor 13 …… Intermodulation detection circuit 16 …… IF elimination filter 17 …… Distortion generation amplifier 18 …… IM extraction filter 21 …… Attenuator drive circuit 22 …… Variable attenuator.
Claims (2)
増幅器と、この高周波増幅器で増幅された信号を局部発
振信号と混合することにより中間周波信号に変換する第
一の周波数変換手段を備えた受信機において、可変減衰
手段と、この可変減衰手段を通過した信号を分配する分
配手段と、この分配された信号を局部発振信号と混合す
ることにより第二の中間周波信号に変換する第二の周波
数変換手段と、第二の中間周波信号のうち受信希望信号
による中間周波信号を除去するIF除去手段と、このIF除
去手段を通過した残余信号を歪ませる歪発生手段と、こ
の歪発生手段で発生し受信希望信号による中間周波信号
と同じ周波数の相互変調信号を抽出するIM抽出手段と、
このIM抽出手段による抽出信号の強度に応じた減衰度制
御電圧を前記可変減衰手段に与える減衰器駆動回路を備
え、前記高周波増幅器の前段に前記可変減衰手段と前記
分配手段を介装したことを特徴とする受信機。1. A reception comprising a high frequency amplifier which is AGC controlled by a desired reception signal, and first frequency conversion means for converting the signal amplified by this high frequency amplifier with a local oscillation signal into an intermediate frequency signal. A variable attenuation means, a distribution means for distributing the signal passed through the variable attenuation means, and a second frequency for converting the distributed signal into a second intermediate frequency signal by mixing with the local oscillation signal. Converting means, IF removing means for removing an intermediate frequency signal of the second desired intermediate frequency signal due to the desired reception signal, distortion generating means for distorting the residual signal passing through this IF removing means, and this distortion generating means IM extraction means for extracting an intermodulation signal having the same frequency as the intermediate frequency signal by the desired reception signal,
It is provided with an attenuator drive circuit for providing the variable attenuation means with an attenuation control voltage according to the intensity of the signal extracted by the IM extraction means, and the variable attenuation means and the distribution means are provided in the preceding stage of the high frequency amplifier. Characteristic receiver.
二の周波数変換手段の局部発振信号は共通の局部発振器
から供給されることを特徴とする特許請求の範囲第１項
に記載の受信機。2. The local oscillation signal of the first frequency conversion means and the local oscillation signal of the second frequency conversion means are supplied from a common local oscillator. Receiving machine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62328114A JPH084236B2 (en) | 1987-12-24 | 1987-12-24 | Receiving machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62328114A JPH084236B2 (en) | 1987-12-24 | 1987-12-24 | Receiving machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01170121A JPH01170121A (en) | 1989-07-05 |
| JPH084236B2 true JPH084236B2 (en) | 1996-01-17 |
Family
ID=18206647
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62328114A Expired - Lifetime JPH084236B2 (en) | 1987-12-24 | 1987-12-24 | Receiving machine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH084236B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0437317A (en) * | 1990-06-01 | 1992-02-07 | Toyo Commun Equip Co Ltd | Method for preventing suppression of sensitivity and crosstalk of receiver |
| US20040043733A1 (en) * | 2002-08-27 | 2004-03-04 | Delphi Technologies, Inc. | Enhanced automatic gain control |
| KR102586051B1 (en) * | 2015-12-18 | 2023-10-06 | (주)디오시스 | Therapy apparatus for diabetic foot ulcers using laser diode |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60160731A (en) * | 1984-02-01 | 1985-08-22 | Fujitsu Ten Ltd | Device for decreasing disturbance of intermodulation of receiver |
-
1987
- 1987-12-24 JP JP62328114A patent/JPH084236B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01170121A (en) | 1989-07-05 |
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