JPH0730449A - Receiver - Google Patents
ReceiverInfo
- Publication number
- JPH0730449A JPH0730449A JP16932893A JP16932893A JPH0730449A JP H0730449 A JPH0730449 A JP H0730449A JP 16932893 A JP16932893 A JP 16932893A JP 16932893 A JP16932893 A JP 16932893A JP H0730449 A JPH0730449 A JP H0730449A
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- interference
- filters
- filter
- interference wave
- 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.)
- Pending
Links
Landscapes
- Noise Elimination (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は複数チャネルを有する
無線システムの受信機、さらに詳しくは該受信機の耐干
渉特性の改善に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver of a radio system having a plurality of channels, and more particularly to improvement of interference resistance of the receiver.
【０００２】[0002]
【従来の技術】図６は、ダブルスーパーヘテロダイン形
受信機の構成を示すブロック図であり、図において、１
は受信アンテナ、２は高周波増幅部で、受信信号からこ
の無線システムの受信周波数帯域内の信号を増幅，ろ波
する。３は第１混合器で、高周波増幅部２からの出力と
受信チャネルに対応する第１局部発振器４からの周波数
を混合して第１中間周波信号を得る。５は第１中間周波
増幅器で、第１中間周波信号を増幅，ろ波する。６は第
２混合器で、増幅，ろ波された第１中間周波信号と第２
局部発振器７からの周波数を混合して第２中間周波信号
を得る。８は第２中間周波数を中心周波数とする受信帯
域制限用フィルタ、９はフィルタ８を通過した信号を増
幅する増幅器、１０は受信電界強度に比例した直流電圧
を発生する検波回路、１１は復調部である。2. Description of the Related Art FIG. 6 is a block diagram showing the structure of a double superheterodyne receiver.
Is a receiving antenna, and 2 is a high-frequency amplifier, which amplifies and filters a signal within the reception frequency band of this wireless system from the received signal. A first mixer 3 mixes the output from the high frequency amplifier 2 and the frequency from the first local oscillator 4 corresponding to the reception channel to obtain a first intermediate frequency signal. A first intermediate frequency amplifier 5 amplifies and filters the first intermediate frequency signal. 6 is a second mixer for amplifying and filtering the first intermediate frequency signal and the second
The frequencies from the local oscillator 7 are mixed to obtain a second intermediate frequency signal. Reference numeral 8 is a reception band limiting filter having a second intermediate frequency as a center frequency, 9 is an amplifier for amplifying a signal passed through the filter 8, 10 is a detection circuit for generating a DC voltage proportional to the received electric field strength, and 11 is a demodulation section. Is.
【０００３】次に動作について説明する。この種の受信
機の動作は良く知られているが、受信アンテナ１で受信
された信号は、高周波増幅部２，第１混合器３，第１中
間周波増幅器５，第２混合器６を経て、中心周波数ｆ0
の第２中間周波信号となる。すなわち、この無線システ
ムで使用する周波数帯域以外の信号は、高周波増幅部２
でろ波され、使用周波数帯域内であっても受信したい信
号以外の信号は、第１中間周波増幅器５および帯域制限
用フィルタ８でろ波され、周波数ｆ0 の受信したい信号
を得ている。然しながら上述のような従来の受信機で
は、希望する信号の周波数に近接する周波数の信号は、
帯域制限用フィルタ８でもろ波しきれずに、干渉波とし
て復調部１１の復調特性を劣化させてしまう。Next, the operation will be described. Although the operation of this type of receiver is well known, the signal received by the receiving antenna 1 passes through the high frequency amplifier 2, the first mixer 3, the first intermediate frequency amplifier 5, and the second mixer 6. , Center frequency f 0
Of the second intermediate frequency signal. That is, signals other than the frequency band used in this wireless system are transferred to the high frequency amplifier 2
Signals other than the signal that is filtered and is not to be received even within the used frequency band are filtered by the first intermediate frequency amplifier 5 and the band limiting filter 8 to obtain the signal to be received at the frequency f 0 . However, in the conventional receiver as described above, the signal of the frequency close to the frequency of the desired signal is
The band-limiting filter 8 cannot completely filter, and deteriorates the demodulation characteristics of the demodulation unit 11 as an interference wave.
【０００４】[0004]
【発明が解決しようとする課題】上記のように従来の受
信機では帯域制限用フィルタの減衰特性によって耐干渉
量が決まってしまい、干渉波の存在によって復調特性が
劣化した場合には通信チャネルを切り換えて干渉を回避
しており、周波数の有効利用という面で無駄があった。As described above, in the conventional receiver, the amount of interference resistance is determined by the attenuation characteristic of the band limiting filter, and when the demodulation characteristic is deteriorated by the presence of the interference wave, the communication channel is changed. Switching was done to avoid interference, and there was a waste of effective use of frequencies.
【０００５】この発明はかかる問題点を解決するために
なされたものであり、耐干渉特性を改善することによ
り、干渉回避のためのチャネル切り換えを少なくし、周
波数の有効利用が図れる受信機を提供することを目的と
している。The present invention has been made in order to solve the above problems, and provides a receiver capable of reducing the channel switching for avoiding interference and improving the effective use of frequency by improving the interference resistance. The purpose is to do.
【０００６】[0006]
【課題を解決するための手段】この発明に係わる受信機
は、中間周波回路で受信帯域を制限するフィルタとし
て、その中心周波数がそれぞれ周波数（ｆ0 ）、周波数
（ｆ0 ＋Δｆ）、周波数（ｆ0 −Δｆ）の３つのフィル
タを備え、それぞれのフィルタに受信信号を通したとき
の受信電界強度の差異を測定し、この測定結果から干渉
波の有無および干渉周波数の高低を判断することを特徴
とする（但し、ｆ0 は中間周波数、Δｆは所定の周波数
偏差である）。In the receiver according to the present invention, as a filter for limiting a reception band in an intermediate frequency circuit, its center frequency is frequency (f 0 ), frequency (f 0 + Δf), frequency (f 0 ). 0- Δf) is provided with three filters, the difference in received electric field strength when the received signal is passed through each filter is measured, and the presence or absence of an interference wave and the level of the interference frequency are determined from the measurement result. (However, f 0 is an intermediate frequency and Δf is a predetermined frequency deviation).
【０００７】また、中間周波回路で受信帯域を制限する
フィルタとして、中心周波数をそれぞれ（ｆ0 ＋Δ
ｆ）、（ｆ0 −Δｆ）とする２つのフィルタを備え、そ
れぞれのフィルタに受信信号を通したときの受信電界強
度の差異を測定し、この測定結果から干渉波の有無およ
び干渉周波数の高低を判断することを特徴とする。Further, as a filter for limiting the reception band in the intermediate frequency circuit, the center frequencies are respectively (f 0 + Δ
f) and (f 0 −Δf) are provided, the difference in the received electric field strength when the received signal is passed through each filter is measured, and the presence or absence of the interference wave and the high and low of the interference frequency are measured from the measurement results. It is characterized by determining.
【０００８】また、所定のスレッショルドレベルを設定
し、このレベルを越える差異がある場合にのみ干渉波が
存在すると判断することを特徴とする。Further, it is characterized in that a predetermined threshold level is set and it is judged that an interference wave exists only when there is a difference exceeding this level.
【０００９】また、これらの手段により干渉波の有無お
よび干渉周波数の高低を判断した結果から複数のフィル
タのうち干渉波の影響が最も少ないフィルタを選択して
当該フィルタを通した信号を復調することを特徴とす
る。Further, from the results of judging the presence or absence of an interference wave and the level of the interference frequency by these means, a filter having the least influence of the interference wave is selected from a plurality of filters and the signal passed through the filter is demodulated. Is characterized by.
【００１０】さらに、復調部内にＡＦＣ機能を備え、こ
のＡＦＣ機能が有効である最大の偏移量を±Δｆ1 とし
た場合、複数のフィルタの減衰特性をそれぞれ等しく
し、且つ、これらのフィルタの中心周波数の差異の最大
を±Δｆ1 としたことを特徴とする。Further, when the demodulation unit has an AFC function and the maximum deviation amount for which the AFC function is effective is ± Δf 1 , the attenuation characteristics of a plurality of filters are made equal to each other, and It is characterized in that the maximum difference between the center frequencies is ± Δf 1 .
【００１１】[0011]
【作用】この発明における受信機は上述のような構成と
することにより、変調方式、変調度、伝送速度を問わ
ず、この種の受信機すべてにおいて干渉波の存在の有
無、干渉周波数の高低を判断でき、且つ、より干渉量の
小さいフィルタを選択することで耐干渉特性を改善で
き、干渉回避のためのチャネル切り換えを少なくでき
る。また、復調部内のＡＦＣにより復調特性の劣化も抑
えられる。By configuring the receiver according to the present invention as described above, regardless of the modulation method, the modulation degree, and the transmission speed, the presence or absence of interference waves and the high and low interference frequencies are present in all receivers of this type. By selecting a filter that can be determined and has a smaller amount of interference, it is possible to improve the anti-interference characteristic and reduce the channel switching for avoiding interference. Further, deterioration of demodulation characteristics can be suppressed by the AFC in the demodulation unit.
【００１２】[0012]
【実施例】実施例１．以下、この発明の実施例を図面を
用いて説明する。図１はこの発明の一実施例を示すブロ
ック図であり、ダブルスーパーヘテロダイン形の受信機
に実施した例を示す。図１において、１は受信アンテ
ナ、２は高周波増幅部で、この無線システムの受信周波
数帯域内の信号を増幅，ろ波する。３は第１混合器で、
高周波増幅部２からの出力と受信チャネルに対応する第
１局部発振器４からの周波数を混合して第１中間周波信
号を得る。５は第１中間周波増幅器で、第１中間周波信
号を増幅，ろ波する。６は第２混合器で、増幅，ろ波さ
れた第１中間周波信号と第２局部発振器７からの周波数
を混合して第２中間周波信号を得る。EXAMPLES Example 1. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, which is an example implemented in a double superheterodyne type receiver. In FIG. 1, reference numeral 1 is a receiving antenna, and 2 is a high-frequency amplifier, which amplifies and filters a signal within the receiving frequency band of this wireless system. 3 is the first mixer,
The output from the high frequency amplifier 2 and the frequency from the first local oscillator 4 corresponding to the reception channel are mixed to obtain a first intermediate frequency signal. A first intermediate frequency amplifier 5 amplifies and filters the first intermediate frequency signal. A second mixer 6 mixes the amplified and filtered first intermediate frequency signal and the frequency from the second local oscillator 7 to obtain a second intermediate frequency signal.
【００１３】８は第２中間周波数（以後ｆ0 とする）を
中心周波数とする受信帯域制限用フィルタ、８ａは中心
周波数をｆ0 ＋Δｆとする受信帯域制限用フィルタ、８
ｂは中心周波数をｆ0 −Δｆとする受信帯域制限用フィ
ルタ、９は受信帯域制限用フィルタ８からの信号を増幅
する増幅器、９ａはフィルタ８ａからの信号を増幅する
増幅器、９ｂはフィルタ８ｂからの信号を増幅する増幅
器、１０は増幅器９からの出力の受信電界強度に比例し
た直流電圧を発生させる検波回路、１０ａは増幅器９ａ
からの出力の受信電界強度に比例した直流電圧を発生さ
せる検波回路、１０ｂは増幅器９ｂからの出力の受信電
界強度に比例した直流電圧を発生させる検波回路、１１
は無線システムの変調方式に対応した復調部で、ＡＦＣ
(Automa-tic Frequency Control)機能を備え、このＡＦ
Ｃがｆ±Δｆ1 の周波数偏差までの受信信号に対して良
好な復調特性を有するとすると、上記フィルタ８ａ，８
ｂのΔｆをこのＡＦＣのΔｆ1 と一致させるように構成
する。復調部１１が周波数変調波の復調を行う復調部で
あるとき、その周波数弁別回路の中心周波数がｆ0 でな
い場合が多い。このような場合は復調部１１内に局部発
振器を設けて信号の中心周波数をｆ0 から上記周波数弁
別回路の中心周波数に変換して復調を行っている。信号
の中心周波数がｆ0 からずれている場合は周波数弁別回
路でこの偏差を検出し、検出した偏差により復調部１１
内の局部発振器の発振周波数をフィードバック制御すれ
ばよい。２１は切換制御回路、２２は切換スイッチで、
後述するように、各増幅器１０，１０ａ，１０ｂそれぞ
れの出力から干渉波の有無およびその干渉量を判定し、
増幅器９，９ａ，９ｂの各出力のうち、一番干渉波の影
響を受けていない出力を復調部１１へ接続する。Reference numeral 8 is a reception band limiting filter having a second intermediate frequency (hereinafter referred to as f 0 ) as a center frequency, 8a is a reception band limiting filter having a center frequency as f 0 + Δf, 8
b is a reception band limiting filter having a center frequency of f 0 −Δf, 9 is an amplifier for amplifying the signal from the reception band limiting filter 8, 9a is an amplifier for amplifying the signal from the filter 8a, and 9b is from the filter 8b. An amplifier for amplifying the signal of 10 is a detection circuit for generating a DC voltage proportional to the received electric field strength of the output from the amplifier 9, and 10a is an amplifier 9a.
A detection circuit for generating a DC voltage proportional to the received electric field strength of the output from the amplifier 10b, a detection circuit for generating a DC voltage proportional to the received electric field strength of the output from the amplifier 9b, 11
Is a demodulation unit corresponding to the modulation system of the wireless system, and AFC
With the (Automa-tic Frequency Control) function, this AF
Assuming that C has a good demodulation characteristic for a received signal up to a frequency deviation of f ± Δf 1 , the filters 8a, 8
The Δf of b is configured to match the Δf 1 of this AFC. When the demodulator 11 is a demodulator that demodulates a frequency-modulated wave, the center frequency of the frequency discriminating circuit is often not f 0 . In such a case, a local oscillator is provided in the demodulator 11 to convert the center frequency of the signal from f 0 to the center frequency of the frequency discriminating circuit for demodulation. When the center frequency of the signal deviates from f 0, the frequency discriminating circuit detects this deviation, and the demodulation unit 11 uses the detected deviation.
The oscillation frequency of the local oscillator in the inside may be feedback-controlled. 21 is a changeover control circuit, 22 is a changeover switch,
As will be described later, the presence or absence of an interference wave and the amount of interference are determined from the output of each amplifier 10, 10a, 10b,
Of the outputs of the amplifiers 9, 9a, 9b, the output least affected by the interference wave is connected to the demodulation unit 11.
【００１４】次に動作について説明する。図２は、受信
帯域制限用フィルタ８，８ａ，８ｂの周波数特性例を示
す図であり、図に示すように、フィルタ８，８ａ，８ｂ
はそれぞれ中心周波数がΔｆずつ異なる以外は、同一の
特性を有する。ここで、増幅器９，９ａ，９ｂの出力を
仮にＳ０，Ｓ＋，Ｓ−、検波回路１０，１０ａ，１０ｂ
の出力を仮にＥ０，Ｅ＋，Ｅ−とすると、受信信号に干
渉波が存在せず、希望する信号周波数のみの場合、受信
電界強度の測定値は、Ｅ０＞Ｅ＋＝Ｅ−となり、これに
よりスイッチ２２は増幅器９の出力Ｓ０を選択する。Next, the operation will be described. FIG. 2 is a diagram showing an example of frequency characteristics of the reception band limiting filters 8, 8a, 8b. As shown in the figure, the filters 8, 8a, 8b are shown.
Have the same characteristics except that the center frequencies differ by Δf. Here, the outputs of the amplifiers 9, 9a, 9b are temporarily S0, S +, S-, and the detection circuits 10, 10a, 10b.
Assuming that the output of E is E0, E +, E-, if there is no interference wave in the received signal and only the desired signal frequency is obtained, the measured value of the received electric field strength becomes E0> E + = E-, which causes the switch 22 selects the output S0 of the amplifier 9.
【００１５】また、受信信号に干渉波が存在する場合、
例えば、希望する信号周波数より高い周波数の干渉波が
存在する場合、受信電界強度の測定値はＥ＋＞Ｅ０＞Ｅ
−となり、これによりスイッチ２２は増幅器９ｂの出力
Ｓ−を選択する。増幅器９ｂの出力Ｓ−は、フィルタ８
ｂの周波数特性により、フィルタ８より高い方の周波数
がΔｆ分制限されており、従って高い周波数の干渉波は
このフィルタ８ｂでろ波され、希望する信号周波数のみ
が復調部１１へ入力される。復調部１１は上述のように
ｆ±Δｆ1 の周波数偏差までの受信信号に対して良好な
復調特性を有するＡＦＣ機能を備えており、従って、フ
ィルタ８，８ａ，８ｂの減衰特性をそれぞれ等しくし、
且つ、これらのフィルタの中心周波数の差異の最大を±
Δｆ1 とすることで、このＡＦＣにより復調特性の劣化
が抑えられ、従って干渉波の影響の少ない復調信号が得
られる。If an interference wave is present in the received signal,
For example, when there is an interference wave with a frequency higher than the desired signal frequency, the measured value of the received electric field strength is E +>E0> E.
-, Which causes the switch 22 to select the output S- of the amplifier 9b. The output S- of the amplifier 9b is the filter 8
Due to the frequency characteristic of b, the frequency higher than that of the filter 8 is limited by Δf. Therefore, the interference wave of higher frequency is filtered by this filter 8b, and only the desired signal frequency is input to the demodulation unit 11. The demodulation unit 11 has the AFC function having a good demodulation characteristic for the received signal up to the frequency deviation of f ± Δf 1 as described above, and therefore the attenuation characteristics of the filters 8, 8a, 8b are made equal to each other. ,
And the maximum difference between the center frequencies of these filters is ±
By setting Δf 1 , it is possible to suppress the deterioration of the demodulation characteristics by this AFC, and thus to obtain a demodulated signal that is less affected by the interference wave.
【００１６】また、逆に希望する信号周波数より低い周
波数の干渉波が存在する場合には、受信電界強度の測定
値はＥ−＞Ｅ０＞Ｅ＋となり、スイッチ２２が増幅器９
ａの出力Ｓ＋を選択することにより、同様にして干渉波
の影響の少ない復調信号が得られる。なお、干渉波が存
在しない場合でも受信信号の内容によって、Ｅ−とＥ＋
とに多少の差異が生じるため、実際には予め有意な差と
認められるスレッショルドレベルを設定しておき、この
レベルを越える差異がある場合に干渉波有りと判断して
上記動作を行い、越えなければ干渉波なしとしてＳ０を
選択するようにすれば、より安定した動作を行わせるこ
とができる。On the contrary, when an interference wave having a frequency lower than the desired signal frequency is present, the measured value of the received electric field strength is E->E0> E +, and the switch 22 causes the amplifier 9 to operate.
By selecting the output S + of a, similarly, a demodulated signal less affected by the interference wave can be obtained. Even if there is no interference wave, depending on the content of the received signal, E- and E +
Therefore, a threshold level that is recognized as a significant difference is actually set in advance, and if there is a difference that exceeds this level, it is judged that there is an interference wave, the above operation is performed, and it must be exceeded. For example, if S0 is selected as no interference wave, more stable operation can be performed.
【００１７】実施例２．なお、上記実施例１ではフィル
タ−増幅器−検波回路を３組の構成としたが、図３に示
すように３個のフィルタ８，８ａ，８ｂの前後に同期し
て動作するスイッチ２２１，２２２を設けて、増幅器
９、検波器１０を共通化してもよい。この場合、切換制
御部２１１は干渉波を監視するために、時分割でスイッ
チ２２１，２２２を切替え、それぞれのフィルタを通過
したときの受信電界強度をそれぞれ記憶して上述の比較
を行い、その結果から適切なフィルタを選択する。Example 2. In the first embodiment, the filter-amplifier-detector circuit is composed of three sets. However, as shown in FIG. 3, the switches 221 and 222 that operate before and after the three filters 8, 8a and 8b are provided. Alternatively, the amplifier 9 and the detector 10 may be provided in common. In this case, in order to monitor the interference wave, the switching control unit 211 switches the switches 221 and 222 in a time division manner, stores the received electric field strengths when passing through the respective filters, and performs the above-mentioned comparison. Select the appropriate filter from.
【００１８】実施例３．また、上記実施例２の構成にお
いて、スイッチ２２１を省略することもできる。この構
成を図４に示す。この場合、切換制御部２１１はスイッ
チ２２２の入力を順次切り換えて、検波器１０の出力変
化を比較し、検波器１０の出力の最小になる入力を選択
することになる。Example 3. Further, the switch 221 may be omitted in the configuration of the second embodiment. This configuration is shown in FIG. In this case, the switching control unit 211 sequentially switches the inputs of the switch 222, compares the output changes of the detector 10, and selects the input that minimizes the output of the detector 10.
【００１９】実施例４．また、上記実施例１ではフィル
タ−増幅器−検波回路を３組の構成としたが、干渉波の
有無を判定するには８ａと８ｂの２つのフィルタで充分
であり、また干渉波が無い場合には、ＡＦＣ機能により
フィルタ８ａを選択してもフィルタ８ｂを選択しても、
フィルタ８を選択したときと復調性能に変わりはないの
で、フィルタ−増幅器−検波回路の構成を、フィルタ８
ａ−増幅器９ａ−検波回路１０ａとフィルタ８ｂ−増幅
器９ｂ−検波回路１０ｂの２組とし、フィルタ８−増幅
器９−検波回路１０を省略することもできる。この構成
を図５に示す。Example 4. In the first embodiment, the filter-amplifier-detector circuit is composed of three sets. However, two filters 8a and 8b are sufficient to determine the presence or absence of an interference wave, and when there is no interference wave. , Whether selecting filter 8a or filter 8b by the AFC function,
Since the demodulation performance is the same as when the filter 8 is selected, the configuration of the filter-amplifier-detection circuit is
It is also possible to use two sets of a-amplifier 9a-detection circuit 10a and filter 8b-amplifier 9b-detection circuit 10b, and omit the filter 8-amplifier 9-detection circuit 10. This structure is shown in FIG.
【００２０】[0020]
【発明の効果】以上のようにこの発明によれば、中心周
波数の異なる３つのフィルタを受信帯域制限用フィルタ
として用いることにより、干渉波の有無および干渉周波
数の高低を判別できるという効果がある。As described above, according to the present invention, the presence or absence of an interference wave and the level of the interference frequency can be discriminated by using three filters having different center frequencies as the reception band limiting filters.
【００２１】また、この判別結果によって、干渉量が最
も小さくなるフィルタを選択して復調することで耐干渉
特性が改善され、周波数の有効利用が図れるという効果
がある。Further, according to the result of this discrimination, by selecting the filter with the smallest amount of interference and demodulating, the anti-interference characteristic is improved, and there is an effect that the frequency can be effectively used.
【００２２】なお、この発明の受信機は、変調方式、変
調度、伝送速度によらず実施することができる。The receiver of the present invention can be implemented irrespective of the modulation method, modulation degree, and transmission rate.
【図１】この発明の実施例１を示すブロック図である。FIG. 1 is a block diagram showing a first embodiment of the present invention.
【図２】この発明におけるフィルタの周波数特性を示す
図である。FIG. 2 is a diagram showing frequency characteristics of a filter according to the present invention.
【図３】この発明の実施例２を示すブロック図である。FIG. 3 is a block diagram showing a second embodiment of the present invention.
【図４】この発明の実施例３を示すブロック図である。FIG. 4 is a block diagram showing a third embodiment of the present invention.
【図５】この発明の実施例４を示すブロック図である。FIG. 5 is a block diagram showing a fourth embodiment of the present invention.
【図６】従来の受信機の構成の一例を示すブロック図で
ある。FIG. 6 is a block diagram showing an example of a configuration of a conventional receiver.
１ 受信アンテナ ２ 高周波増幅部 ３ 第１混合器 ４ 第１局部発振器 ５ 第１中間周波増幅器 ６ 第２混合器 ７ 第２局部発振器 ８，８ａ，８ｂ 受信帯域制限フィルタ ９，９ａ，９ｂ 増幅器 １０，１０ａ，１０ｂ 検波回路 １１ 復調部 ２１ 切換制御回路 ２２ 切換スイッチ ２１１ 切換制御部 ２２１，２２２ 切換スイッチ DESCRIPTION OF SYMBOLS 1 receiving antenna 2 high frequency amplification part 3 1st mixer 4 1st local oscillator 5 1st intermediate frequency amplifier 6 2nd mixer 7 2nd local oscillator 8,8a, 8b reception band limiting filter 9,9a, 9b amplifier 10, 10a, 10b Detection circuit 11 Demodulation unit 21 Changeover control circuit 22 Changeover switch 211 Changeover control unit 221, 222 Changeover switch
Claims (5)
ルタとして、その中心周波数がそれぞれ周波数（ｆ
0 ）、周波数（ｆ0 ＋Δｆ）、周波数（ｆ0 −Δｆ）の
（但し、ｆ0 は中間周波数、Δｆは所定量の周波数偏
差）、３つのフィルタを備え、 それぞれのフィルタに受信信号を通したときの受信電界
強度の差異を測定し、この測定結果から干渉波の有無お
よび干渉周波数の高低を判断する手段、 を備えたことを特徴とする受信機。1. As a filter for limiting a reception band in an intermediate frequency circuit, its center frequency is a frequency (f
0 ), frequency (f 0 + Δf), and frequency (f 0 −Δf) (where f 0 is an intermediate frequency and Δf is a predetermined amount of frequency deviation), three filters are provided, and the received signal is passed through each filter. A receiver comprising means for measuring a difference in received electric field strength at the time, and determining the presence or absence of an interference wave and the level of the interference frequency from the measurement result.
ルタとして、中間周波数をｆ0 、所定量の周波数偏差を
Δｆとする場合、中心周波数をそれぞれ（ｆ0 ＋Δ
ｆ）、（ｆ0 −Δｆ）とする２つのフィルタを備え、 それぞれのフィルタに受信信号を通したときの受信電界
強度の差異を測定し、この測定結果から干渉波の有無お
よび干渉周波数の高低を判断する手段、 を備えたことを特徴とする受信機。2. As a filter for limiting a reception band in an intermediate frequency circuit, when the intermediate frequency is f 0 and a predetermined amount of frequency deviation is Δf, the center frequency is (f 0 + Δ).
f) and (f 0 −Δf) are provided, and the difference in received electric field strength when the received signal is passed through each filter is measured. From the measurement result, the presence or absence of an interference wave and the high and low of the interference frequency are measured. A receiver having means for judging.
を判断する手段は、所定のスレッショルドレベルを設定
し、このレベルを越える差異がある場合にのみ干渉波が
存在すると判断することを特徴とする請求項第１項また
は第２項記載の受信機。3. The means for determining the presence or absence of an interference wave based on the difference in the electric field strength sets a predetermined threshold level, and determines that the interference wave exists only when there is a difference exceeding this level. The receiver according to claim 1 or 2.
周波数の高低を判断した結果から上記複数のフィルタの
うち干渉波の影響が最も少ないフィルタを選択して当該
フィルタを通した信号を復調する手段、 を備えたことを特徴とする請求項第１項，第２項，また
は第３項記載の受信機。4. A means for demodulating a signal passed through the filter by selecting a filter having the least influence of the interference wave from the plurality of filters based on the result of the presence / absence of the interference wave and the level of the interference frequency determined by the means. The receiver according to claim 1, 2, or 3, characterized in that.
機能を有し、このＡＦＣ機能が有効である最大の変位量
を±Δｆ1 とした場合、上記複数のフィルタの減衰特性
をそれぞれ等しくし、且つ、これらのフィルタの中心周
波数の差異の最大をｆ0 ±Δｆ1 としたことを特徴とす
る請求項第４項記載の受信機。5. AFC (Automatic Frequency Control)
When the maximum displacement amount that has a function and this AFC function is effective is ± Δf 1 , the attenuation characteristics of the plurality of filters are made equal to each other, and the maximum difference between the center frequencies of these filters is f. 5. The receiver according to claim 4, wherein 0 ± Δf 1 is set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16932893A JPH0730449A (en) | 1993-07-08 | 1993-07-08 | Receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16932893A JPH0730449A (en) | 1993-07-08 | 1993-07-08 | Receiver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0730449A true JPH0730449A (en) | 1995-01-31 |
Family
ID=15884518
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16932893A Pending JPH0730449A (en) | 1993-07-08 | 1993-07-08 | Receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0730449A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1079601A (en) * | 1996-09-02 | 1998-03-24 | Nec Corp | Filter |
| JP2010508755A (en) * | 2006-11-01 | 2010-03-18 | トムソン ライセンシング | Co-channel interference canceller |
-
1993
- 1993-07-08 JP JP16932893A patent/JPH0730449A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1079601A (en) * | 1996-09-02 | 1998-03-24 | Nec Corp | Filter |
| JP2010508755A (en) * | 2006-11-01 | 2010-03-18 | トムソン ライセンシング | Co-channel interference canceller |
| US8290464B2 (en) | 2006-11-01 | 2012-10-16 | Thomson Licensing | Co-channel interference remover |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0430469B1 (en) | A signal quality detecting circuit for FM receivers | |
| JP3298911B2 (en) | Wireless receiver | |
| US5598430A (en) | Analog/digital receiver | |
| US6826418B2 (en) | Radio circuit and control method of radio circuit | |
| JPH06509691A (en) | Adjacent channel controller for radio receivers | |
| JPH0544209B2 (en) | ||
| US6356746B1 (en) | Direct converting receiver | |
| CA2089259C (en) | Transient suppression circuit for a time domain duplex transceiver | |
| US4726073A (en) | Receiver including a multipath transmission detector | |
| JP3992521B2 (en) | Adjacent interference detection apparatus and method, and broadcast receiving apparatus capable of using the method | |
| AU784709B2 (en) | Method and circuit for avoiding band interferance wave in receiver | |
| KR100717438B1 (en) | Fm receiver with bandwidth control means | |
| JPH07231273A (en) | Tuner for receiving satellite broadcast | |
| JPH0730449A (en) | Receiver | |
| JP4121410B2 (en) | Signal detecting apparatus and receiving apparatus capable of using the apparatus | |
| JP3220920B2 (en) | AM receiver | |
| JP3675138B2 (en) | Receiving machine | |
| JPS6141321Y2 (en) | ||
| JP3157283B2 (en) | Receiving machine | |
| JPS59147546A (en) | Receiver | |
| JPH0897738A (en) | Radio receiver | |
| JP3157281B2 (en) | Receiving machine | |
| JPS6259938B2 (en) | ||
| JP2005175784A (en) | Fm radio receiver | |
| JP2009105729A (en) | Fm radio receiver |