JPH04365229A - Pulse noise removing circuit - Google Patents
Pulse noise removing circuitInfo
- Publication number
- JPH04365229A JPH04365229A JP14196191A JP14196191A JPH04365229A JP H04365229 A JPH04365229 A JP H04365229A JP 14196191 A JP14196191 A JP 14196191A JP 14196191 A JP14196191 A JP 14196191A JP H04365229 A JPH04365229 A JP H04365229A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- noise
- gate
- pulse
- pulse noise
- 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.)
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- 230000005684 electric field Effects 0.000 claims abstract description 29
- 238000001514 detection method Methods 0.000 claims abstract description 20
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 claims abstract description 13
- 239000003990 capacitor Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 2
- 101710162453 Replication factor A Proteins 0.000 description 1
- 102100035729 Replication protein A 70 kDa DNA-binding subunit Human genes 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
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Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、ＦＭラジオ受信機で受
信された受信信号中に含まれるパルスノイズを除去する
ためのパルスノイズ除去回路に関するもので、特に弱電
界受信時における情報量の減少を防止せんとするもので
ある。[Industrial Application Field] The present invention relates to a pulse noise removal circuit for removing pulse noise contained in a received signal received by an FM radio receiver, and particularly relates to a reduction in the amount of information when receiving a weak electric field. The aim is to prevent this.
【０００２】0002
【従来の技術】耳障りなパルスノイズを除去する為、受
信信号中に含まれるパルスノイズを検出し、少なくとも
前記パルスノイズの発生期間中、信号路に配置されるゲ
ート回路を制御し、ノイズの発生を防止するパルスノイ
ズ除去回路が知られている。しかして、このようなパル
スノイズ除去回路においては、パルスノイズに応じて動
作するゲート信号発生回路を備えており、該ゲート信号
発生回路から発生するゲート信号のパルス幅に対応する
期間中、パルスノイズの除去が行われる。[Prior Art] In order to remove unpleasant pulse noise, the pulse noise contained in a received signal is detected, and a gate circuit placed in a signal path is controlled at least during the period in which the pulse noise is generated. Pulse noise removal circuits that prevent this are known. However, such a pulse noise removal circuit includes a gate signal generation circuit that operates according to the pulse noise, and during a period corresponding to the pulse width of the gate signal generated from the gate signal generation circuit, the pulse noise is removed. is removed.
【０００３】0003
【発明が解決しようとする課題】従来のパルスノイズ除
去回路は、ゲート信号のパルス幅がパルスノイズを効果
的に除去し得る所定値に、例えば４０μＳに固定されて
いた。このパルスノイズ除去回路は、自動車のイグニッ
ションノイズ等のパルスノイズを効果的に除去すること
ができる。In the conventional pulse noise removal circuit, the pulse width of the gate signal is fixed to a predetermined value that can effectively remove pulse noise, for example, 40 μS. This pulse noise removal circuit can effectively remove pulse noise such as automobile ignition noise.
【０００４】しかしながら、弱電界受信時においては、
前記パルスノイズ除去回路が過変調ノイズ等によって誤
動作するという問題が生じる。即ち、弱電界受信時には
、弱電界ノイズのレベルが大になるが、この弱電界ノイ
ズは、ノイズＡＧＣによりそのレベルが抑圧され、パル
スノイズ検出回路で検出されない。ところが、弱電界時
に過変調ノイズが混入すると、弱電界ノイズに過変調ノ
イズが重畳されてパルス的となり、しかもこのノイズが
パルスノイズよりも大なる頻度で発生する。この疑似パ
ルスノイズは、パルスノイズ検出回路で検出され、ゲー
トを頻繁に開閉する。その為、ゲートの開期間中必要な
情報が失われるという問題が生じる。However, when receiving a weak electric field,
A problem arises in that the pulse noise removal circuit malfunctions due to overmodulation noise or the like. That is, when receiving a weak electric field, the level of weak electric field noise increases, but the level of this weak electric field noise is suppressed by the noise AGC and is not detected by the pulse noise detection circuit. However, when overmodulation noise is mixed in when the electric field is weak, the overmodulation noise is superimposed on the weak electric field noise and becomes pulse-like, and this noise occurs more frequently than the pulse noise. This pseudo pulse noise is detected by a pulse noise detection circuit, which frequently opens and closes the gate. Therefore, a problem arises in that necessary information is lost while the gate is open.
【０００５】最近は、パルスノイズによる受信妨害より
も、上述の疑似パルスノイズによる情報消失のほうがよ
り問題となってきた。[0005] Recently, information loss due to the above-mentioned pseudo pulse noise has become more of a problem than reception interference due to pulse noise.
【０００６】[0006]
【課題を解決するための手段】本発明は、上述の点に鑑
み成されたもので、疑似パルスノイズに対しても効果の
あるパルスノイズ除去回路を提供せんとするもので、パ
ルスノイズ検出回路と、ゲート信号発生回路と、ゲ−ト
回路と、受信信号の電界強度又は受信信号中に含まれる
連続ノイズの量に応じてゲート信号発生回路を制御する
制御回路とを備える点を特徴とする。[Means for Solving the Problems] The present invention has been made in view of the above-mentioned points, and it is an object of the present invention to provide a pulse noise removal circuit that is also effective against pseudo pulse noise. and a gate signal generation circuit, a gate circuit, and a control circuit that controls the gate signal generation circuit according to the electric field strength of the received signal or the amount of continuous noise contained in the received signal. .
【０００７】[0007]
【作用】本発明によれば、中強電界時には、ゲート信号
発生回路の出力パルス幅を大（約４０μＳ）とすること
が出来るので、イグニッションノイズ等の比較的発生周
期の長いパルスノイズを有効に除去することができる。
又、弱電界時には、ゲート信号発生回路の出力パルス幅
を小（約２０μＳ）とすることが出来るので、頻度の高
い過変調ノイズ等に起因する情報消失を防止できる。[Operation] According to the present invention, the output pulse width of the gate signal generation circuit can be made large (approximately 40 μS) during medium-strong electric fields, so that pulse noise with a relatively long generation period, such as ignition noise, can be effectively processed. Can be removed. Furthermore, in the case of a weak electric field, the output pulse width of the gate signal generation circuit can be made small (approximately 20 μS), so that information loss caused by frequently occurring overmodulation noise can be prevented.
【０００８】[0008]
【実施例】図１は、本発明の一実施例を示す回路図で、
（１）は受信アンテナ、（２）はアンテナ（１）に受信
されたＲＦ信号を増幅するＲＦ増幅回路、（３）はＲＦ
増幅回路（２）の出力信号と局部発振回路（４）の出力
信号とを混合する混合回路、（５）は混合回路（３）の
出力ＩＦ信号を増幅するＩＦ増幅回路、（６）はＩＦ増
幅回路の出力ＩＦ信号をＦＭ検波するＦＭ検波回路、（
７）はＦＭ検波回路（６）の出力端に接続されたバッフ
ァ回路、（８）はバッファ回路（７）の出力信号中に含
まれるパルスノイズを除去するゲート回路、（９）はＦ
Ｍ検波回路（６）の出力信号中に含まれる高周波ノイズ
成分を通過させるハイパスフィルター、（１０）はパル
スノイズ検出回路、（１１）はハイパスフィルタ（９）
の出力信号中に含まれる連続ノイズに応じてＡＧＣを行
うノイズＡＧＣ回路、（１２）はパルスノイズ検出回路
（１０）の出力信号に応じて動作する単安定マルチバイ
ブレータ、（１３）は受信信号の電界強度を示す信号を
発生する制御回路、（１４）は制御回路（１３）の出力
信号に応じて単安定マルチバイブレータ（１１）の時定
数を切換える時定数切換回路である。尚、単安定マルチ
バイブレータ（１２）と時定数切換回路（１４）とは、
ゲート信号発生回路を構成している。[Embodiment] FIG. 1 is a circuit diagram showing an embodiment of the present invention.
(1) is a receiving antenna, (2) is an RF amplifier circuit that amplifies the RF signal received by antenna (1), and (3) is an RF
A mixing circuit that mixes the output signal of the amplifier circuit (2) and an output signal of the local oscillation circuit (4), (5) an IF amplifier circuit that amplifies the output IF signal of the mixing circuit (3), and (6) an IF FM detection circuit that FM detects the output IF signal of the amplifier circuit, (
7) is a buffer circuit connected to the output terminal of the FM detection circuit (6), (8) is a gate circuit that removes pulse noise contained in the output signal of the buffer circuit (7), and (9) is an F
A high-pass filter that passes high-frequency noise components contained in the output signal of the M detection circuit (6), (10) a pulse noise detection circuit, and (11) a high-pass filter (9).
(12) is a monostable multivibrator that operates according to the output signal of the pulse noise detection circuit (10); (13) is a noise AGC circuit that performs AGC according to the continuous noise contained in the output signal of the received signal; The control circuit (14) that generates a signal indicating the electric field strength is a time constant switching circuit that switches the time constant of the monostable multivibrator (11) according to the output signal of the control circuit (13). Furthermore, the monostable multivibrator (12) and time constant switching circuit (14) are as follows.
It constitutes a gate signal generation circuit.
【０００９】次に動作を説明する。アンテナ（１）に受
信された信号は、ＲＦ増幅回路（２）で増幅されたのち
混合回路（３）において局部発振回路（４）の出力信号
と混合され、ＩＦ信号に変換される。前記ＩＦ信号は、
ＩＦ増幅回路（５）で増幅され、ＦＭ検波回路（６）で
ＦＭ検波される。その後、ＦＭ検波回路（６）の出力信
号は、バッファ回路（７）及びゲート回路（８）を介し
て出力端子に導出される。Next, the operation will be explained. The signal received by the antenna (1) is amplified by the RF amplifier circuit (2), mixed with the output signal of the local oscillation circuit (4) in the mixing circuit (3), and converted into an IF signal. The IF signal is
The signal is amplified by the IF amplifier circuit (5) and subjected to FM detection by the FM detection circuit (6). Thereafter, the output signal of the FM detection circuit (6) is led out to the output terminal via the buffer circuit (7) and the gate circuit (8).
【００１０】ＦＭ検波回路（６）の出力信号中の高周波
ノイズ成分は、ハイパスフィルター（９）を通過し、パ
ルスノイズ検出回路（１０）に印加され、そこでパルス
ノイズの検出が行われる。パルスノイズ検出回路（１０
）に対しては、ノイズＡＧＣ回路（１１）によって連続
ノイズレベルに応じたＡＧＣがかけられているので、パ
ルスノイズ検出回路（１０）は所定レベル以上のパルス
ノイズのみを検出することができる。検出されたパルス
ノイズは、単安定マルチバイブレータ（１２）にトリガ
として印加される。その為、単安定マルチバイブレータ
（１２）の出力には、検出されたパルスノイズのタイミ
ングを持ち、所定のパルス幅を持ったゲート信号が発生
する。The high-frequency noise component in the output signal of the FM detection circuit (6) passes through a high-pass filter (9) and is applied to a pulse noise detection circuit (10), where pulse noise is detected. Pulse noise detection circuit (10
), the noise AGC circuit (11) applies AGC according to the continuous noise level, so the pulse noise detection circuit (10) can detect only pulse noise of a predetermined level or higher. The detected pulse noise is applied as a trigger to the monostable multivibrator (12). Therefore, a gate signal having the timing of the detected pulse noise and a predetermined pulse width is generated at the output of the monostable multivibrator (12).
【００１１】ところで、単安定マルチバイブレータ（１
２）の時定数は、時定数切換回路（１４）の出力に応じ
て切換わる。今、受信信号の電界強度が中または強であ
るとすれば、電界強度を検出する制御回路（１３）の出
力信号は、第１の値（例えばＬ）となり、時定数切換回
路（１４）の出力信号も第１の値となり、単安定マルチ
バイブレータ（１２）の時定数は比較的長い第１の値（
例えば４０μＳ）となる。その為、ゲート信号のパルス
幅（４０μＳ）が、パルスノイズを効果的に除去し得る
値となり、図１のパルスノイズ除去回路は、除去機能を
十分に発揮する。By the way, monostable multivibrator (1
The time constant 2) is switched according to the output of the time constant switching circuit (14). Now, if the electric field strength of the received signal is medium or strong, the output signal of the control circuit (13) that detects the electric field strength will be the first value (for example, L), and the output signal of the control circuit (13) that detects the electric field strength will be the first value (for example, L). The output signal also has the first value, and the time constant of the monostable multivibrator (12) has a relatively long first value (
For example, 40 μS). Therefore, the pulse width (40 μS) of the gate signal is a value that can effectively remove pulse noise, and the pulse noise removal circuit shown in FIG. 1 fully exhibits its removal function.
【００１２】一方、受信信号の電界強度が弱くなると、
制御回路（１３）の出力信号が第２の値（たとえばＨ）
となり、時定数切換回路（１４）の値も第２の値となり
、単安定マルチバイブレータ（１２）の時定数は比較的
短い第２の値（例えば２０μＳ）となる。その為、弱電
界受信時に、過変調ノイズ等が発生し、単安定マルチバ
イブレータ（１２）が動作し、ゲート回路（８）が動作
したとしても、信号及びノイズの遮断期間が短くなり、
情報の消失量が少なくなる。一般に、弱電界受信時には
、ノイズ量が多くなるので、パルスノイズの除去よりも
情報の確保を優先したほうが、聴取者に対し良好な受信
を提供し得る。On the other hand, when the electric field strength of the received signal becomes weaker,
The output signal of the control circuit (13) has a second value (for example, H)
Therefore, the value of the time constant switching circuit (14) also becomes the second value, and the time constant of the monostable multivibrator (12) becomes a relatively short second value (for example, 20 μS). Therefore, when receiving a weak electric field, overmodulation noise etc. occur, and even if the monostable multivibrator (12) operates and the gate circuit (8) operates, the signal and noise interruption period will be shortened.
The amount of information lost is reduced. Generally, when receiving a weak electric field, the amount of noise increases, so giving priority to ensuring information over removing pulse noise can provide listeners with better reception.
【００１３】上述の説明においては、受信信号が弱電界
であることを、受信信号の電界強度を検出する制御回路
（１３）を用いて検出している。しかしながら、弱電界
の検出は、他の方法、例えば、ノイズＡＧＣ回路を用い
ることによっても検出することができる。即ち、図１に
示す如く、弱電界時に大となる連続ノイズをノイズＡＧ
Ｃ回路（１１）から取り出し、制御回路（１３’）でそ
のレベルを検出して制御信号を発生すれば、弱電界時に
時定数切換回路（１４）を制御することができ、制御回
路（１３）を用いた場合と全く同じ結果を得ることがで
きる。In the above description, the fact that the received signal has a weak electric field is detected using a control circuit (13) that detects the electric field strength of the received signal. However, the detection of weak electric fields can also be detected in other ways, for example by using a noise AGC circuit. In other words, as shown in Figure 1, the continuous noise that becomes large when the electric field is weak is converted into noise AG.
If the level is detected by the control circuit (13') and a control signal is generated from the C circuit (11), the time constant switching circuit (14) can be controlled in the case of a weak electric field, and the control circuit (13) You can get exactly the same results as using .
【００１４】図２は、図１の単安定マルチバイブレータ
（１２）及び時定数切換回路（１４）の具体回路例を示
す回路図である。図２において、入力端子（１５）には
、図１のパルスノイズ検出回路（１０）の出力信号が印
加される。前記入力端子（１５）に信号が印加されると
、トランジスタ（１６）がオンし、コンデンサ（１７）
の充電が行われる。コンデンサ（１７）が放電している
初期状態においては、トランジスタ（１８）がオフ、ト
ランジスタ（１９）がオンとなっている。その為、トラ
ンジスタ（２０）がオン、トランジスタ（２１）がオフ
となり、出力端子（２２）にＬレベルの出力信号が発生
している。コンデンサ（１７）の充電が進みトランジス
タ（１８）のベース電圧がトランジスタ（１９）のベー
ス電圧を越えると、トランジスタ（１８）がオン、トラ
ンジスタ（１９）がオフとなり、トランジスタ（２０）
がオフ、トランジスタ（２１）がオンとなって、出力端
子（２２）にＨレベルの出力信号が発生する。その後、
コンデンサ（１７）の電荷は、抵抗（２３）を介して放
電され、トランジスタ（１８）のベ−ス電圧がトランジ
スタ（１９）のベース電圧よりも低下すると、再びトラ
ンジスタ（１８）がオフ、トランジスタ（１９）がオン
となり、トランジスタ（２０）がオン、トランジスタ（
２１）がオフとなって、出力信号がＬレベルとなる。コ
ンデンサ（１７）と抵抗（２３）との放電時定数は、約
４０μＳに設定されているので、出力端子（２２）に得
られる出力信号のパルス幅も約４０μＳとなる。FIG. 2 is a circuit diagram showing a specific circuit example of the monostable multivibrator (12) and time constant switching circuit (14) of FIG. 1. In FIG. 2, the output signal of the pulse noise detection circuit (10) of FIG. 1 is applied to the input terminal (15). When a signal is applied to the input terminal (15), the transistor (16) turns on and the capacitor (17)
charging is performed. In the initial state where the capacitor (17) is discharging, the transistor (18) is off and the transistor (19) is on. Therefore, the transistor (20) is turned on, the transistor (21) is turned off, and an L level output signal is generated at the output terminal (22). When the capacitor (17) is charged and the base voltage of the transistor (18) exceeds the base voltage of the transistor (19), the transistor (18) turns on, the transistor (19) turns off, and the transistor (20) turns on.
is off, the transistor (21) is turned on, and an H-level output signal is generated at the output terminal (22). after that,
The charge in the capacitor (17) is discharged through the resistor (23), and when the base voltage of the transistor (18) becomes lower than the base voltage of the transistor (19), the transistor (18) is turned off again and the transistor ( 19) turns on, transistor (20) turns on, transistor (
21) is turned off, and the output signal becomes L level. Since the discharge time constant of the capacitor (17) and the resistor (23) is set to about 40 μS, the pulse width of the output signal obtained at the output terminal (22) is also about 40 μS.
【００１５】中強電界受信時には、図１の制御回路（１
３）の出力信号がＬレベルとなっているので、トランジ
スタ（２４）がオフとなり、コンデンサ（１７）の放電
時定数は上述の如くコンデンサ（１７）の容量と抵抗（
２３）の抵抗値とによって定まる。又、弱電界受信時に
は、制御回路（１３）の出力信号がＨレベルとなるので
、トランジスタ（２４）がオンとなり、コンデンサ（１
７）の放電時定数は、コンデンサ（１７）の容量と抵抗
（２３）及び（２５）の並列抵抗値とによって定まる。
抵抗（２５）の抵抗値を適切に定めれば、弱電界受信時
におけるコンデンサ（１７）の放電時定数を２０μＳに
することができ、出力端子（２２）に得られる出力信号
のパルス幅を約２０μＳにすることができる。When receiving a medium-strong electric field, the control circuit (1
Since the output signal of 3) is at the L level, the transistor (24) is turned off, and the discharge time constant of the capacitor (17) is determined by the capacitance of the capacitor (17) and the resistance (
23). Furthermore, when receiving a weak electric field, the output signal of the control circuit (13) becomes H level, so the transistor (24) turns on and the capacitor (1
The discharge time constant of 7) is determined by the capacitance of the capacitor (17) and the parallel resistance value of the resistors (23) and (25). If the resistance value of the resistor (25) is appropriately determined, the discharge time constant of the capacitor (17) when receiving a weak electric field can be set to 20 μS, and the pulse width of the output signal obtained at the output terminal (22) can be made approximately It can be set to 20 μS.
【００１６】[0016]
【発明の効果】以上述べた如く、本発明によれば、パル
スノイズを検出したとき、受信信号の電界強度に応じて
ゲート駆動用のパルスの幅を変更することができるので
、中強電界時にはパルス幅を広くしてパルスノイズを確
実に除去することができ、弱電界時にはパルス幅を狭く
して情報の不要な消失を防止できる。As described above, according to the present invention, when pulse noise is detected, the width of the gate driving pulse can be changed according to the electric field strength of the received signal. Pulse noise can be reliably removed by widening the pulse width, and when the electric field is weak, the pulse width can be narrowed to prevent unnecessary loss of information.
【図１】本発明の一実施例を示す回路図[Fig. 1] Circuit diagram showing one embodiment of the present invention
【図２】図１の
単安定マルチバイブレータ（１２）及び時定数切換回路
（１４）の具体回路例を示す回路図[Figure 2] A circuit diagram showing a specific circuit example of the monostable multivibrator (12) and time constant switching circuit (14) in Figure 1.
（８） ゲート回路
（１０） パルスノイズ検出回路
（１１） ノイズＡＧＣ回路
（１２） 単安定マルチバイブレータ（１３） 制
御回路
（１４） 時定数切換回路(8) Gate circuit (10) Pulse noise detection circuit (11) Noise AGC circuit (12) Monostable multivibrator (13) Control circuit (14) Time constant switching circuit
Claims (2)
ためのパルスノイズ除去回路であって、受信信号中に含
まれるパルスノイズを検出する検出回路と、該検出回路
の出力信号に応じてゲ−ト信号を発生するゲート信号発
生回路と、前記ゲート信号に応じてパルスノイズを除去
するゲ−ト回路と、受信信号の電界強度または受信信号
中に含まれる連続ノイズに応じて前記ゲート信号発生回
路を制御する制御回路とからなるパルスノイズ除去回路
。1. A pulse noise removal circuit for removing pulse noise in a received signal, the circuit comprising: a detection circuit for detecting pulse noise contained in the received signal; a gate signal generation circuit that generates a gate signal; a gate circuit that removes pulse noise according to the gate signal; and a gate signal generation circuit that removes pulse noise according to the electric field strength of the received signal or continuous noise contained in the received signal. A pulse noise removal circuit consisting of a control circuit and a control circuit.
ルチバイブレータからなり、前記制御回路は前記単安定
マルチバイブレータの時定数を制御することを特徴とす
る請求項１記載のパルスノイズ除去回路。2. The pulse noise removal circuit according to claim 1, wherein the gate signal generation circuit includes a monostable multivibrator, and the control circuit controls a time constant of the monostable multivibrator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3141961A JP2680746B2 (en) | 1991-06-13 | 1991-06-13 | Pulse noise removal circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3141961A JP2680746B2 (en) | 1991-06-13 | 1991-06-13 | Pulse noise removal circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04365229A true JPH04365229A (en) | 1992-12-17 |
| JP2680746B2 JP2680746B2 (en) | 1997-11-19 |
Family
ID=15304154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3141961A Expired - Lifetime JP2680746B2 (en) | 1991-06-13 | 1991-06-13 | Pulse noise removal circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2680746B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6788923B2 (en) * | 2000-02-23 | 2004-09-07 | Mitsubishi Denki Kabushiki Kaisha | Receiver noise reduction with expanding gated pulses |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3009542U (en) * | 1994-09-28 | 1995-04-04 | 瀧定株式会社 | Hanging hook |
-
1991
- 1991-06-13 JP JP3141961A patent/JP2680746B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3009542U (en) * | 1994-09-28 | 1995-04-04 | 瀧定株式会社 | Hanging hook |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6788923B2 (en) * | 2000-02-23 | 2004-09-07 | Mitsubishi Denki Kabushiki Kaisha | Receiver noise reduction with expanding gated pulses |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2680746B2 (en) | 1997-11-19 |
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