JPH0659101B2 - Polarizer control circuit for satellite receiver - Google Patents
Polarizer control circuit for satellite receiverInfo
- Publication number
- JPH0659101B2 JPH0659101B2 JP21821185A JP21821185A JPH0659101B2 JP H0659101 B2 JPH0659101 B2 JP H0659101B2 JP 21821185 A JP21821185 A JP 21821185A JP 21821185 A JP21821185 A JP 21821185A JP H0659101 B2 JPH0659101 B2 JP H0659101B2
- Authority
- JP
- Japan
- Prior art keywords
- output
- circuit
- polarizer
- polarization
- filter
- 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
Links
- 230000010287 polarization Effects 0.000 claims description 67
- 238000001514 detection method Methods 0.000 claims description 21
- 230000003321 amplification Effects 0.000 claims description 2
- 230000002238 attenuated effect Effects 0.000 claims description 2
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 2
- 230000007257 malfunction Effects 0.000 description 7
- 238000001228 spectrum Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 239000000969 carrier Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
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Description
【発明の詳細な説明】 産業上の利用分野 本発明は衛星より送られてくる偏波面の異なる複数のテ
レビジョン信号を受信する衛星放送受信機の偏波器制御
回路に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizer control circuit of a satellite broadcast receiver that receives a plurality of television signals having different polarization planes transmitted from a satellite.
従来の技術 従来より、米国等４GHz帯（Ｃバンド）の衛星放送（テ
レビジョン信号）は、偏波面が垂直と水平の２種類の信
号から成っている。例えば１つの衛星から２４チャンネ
ル（3.72〜4.18GHz）のテレビ信号が発射されている
時、奇数チャンネルは垂直、偶数チャンネルは水平の偏
波面で送られる。（逆の偏波面の衛星もある）各チャン
ネルは占有帯域４０MHzで、ＣＨスペースは２０MHzであ
り、偏波面を切換えて、混信を防いでいる。受信アンテ
ナの焦点に設けられた偏波器で、垂直又は水平のいずれ
かの偏波面の信号を取り出し、偏波器の後方に設けられ
た低雑音コンバータ（ＬＮＢ）へ伝える構成となってい
る。第３図は上述した従来の衛星放送受信機の構成を示
すものである。第３図において、１はアンテナ、２は偏
波器、３はＬＮＢ、４ａ，４ｂはＬＮＢ３，偏波器２の
支柱で、支柱４ｂに沿って、信号ケーブル及び偏波器３
への電力，制御信号伝送線５が設置されている。６はア
ンテナ１の支柱で、アンテナ１の抑角及び方向（東向或
は西向）が変化できる事は言うでもない。７は衛星放送
受信機であり、以下の構成要素から成っている。８は２
ｎｄミキサーとも呼ばれるチューナーで、ＬＮＢ３で3.
72〜4.18GHzの中心周波数の２４波を９７０〜１４３０M
Hzの２４波に変換し、チューナ８で、その中の一波に同
調する。チューナー８の出力は５１０MHzのＩＦ周波数
で、帯域は例えば２５MHzある。９は映像中間波増幅回
路（以下ＩＦ回路という）で、帯域通過波器(B.P.F)
を含んでいる。１０は広帯域のＦＭ検波回路で、例えば
ＰＬＬ検波が使われる。１１はＦＭ検波回路１０の出力
中の音声搬送波をＦＭ検波する音声検波回路で、この音
声検波回路１１の出力を音声信号処理回路１３で適当な
レベルと、周波数特性に変換し、出力すると共にＲＦコ
ンバータ１４へ音声信号処理回路１３の出力を供給す
る。一方、映像信号処理回路１２では、4.2MHz以上の高
域成分と、エネルギー拡散信号を除去し、適当なレベル
で出力すると共にＲＦコンバータ14へ映像信号処理回路
１２の出力を供給する。１５は自動偏波制御回路で、偏
波面を変化させて、最適点で停止させる。2. Description of the Related Art Conventionally, satellite broadcasting (television signals) in the 4 GHz band (C band) such as the United States is composed of two types of signals whose polarization planes are vertical and horizontal. For example, when a television signal of 24 channels (3.72 to 4.18 GHz) is emitted from one satellite, the odd channel is sent in the vertical polarization plane and the even channel is sent in the horizontal polarization plane. Each channel (there are also satellites with opposite polarization planes) has an occupied band of 40 MHz and CH space is 20 MHz, and the polarization planes are switched to prevent interference. A polarizer provided at the focal point of the receiving antenna takes out a signal on either a vertical or horizontal polarization plane and transmits it to a low noise converter (LNB) provided behind the polarizer. FIG. 3 shows the configuration of the conventional satellite broadcast receiver described above. In FIG. 3, 1 is an antenna, 2 is a polarizer, 3 is an LNB, 4a and 4b are LNB3, and a pillar of the polarizer 2 is provided. A signal cable and a polarizer 3 are provided along the pillar 4b.
A power and control signal transmission line 5 is installed. Needless to say, 6 is a column of the antenna 1, and the angle of depression and direction (eastward or westward) of the antenna 1 can be changed. Reference numeral 7 is a satellite broadcast receiver, which is composed of the following components. 8 is 2
This tuner is also called the nd mixer, and LNB3 is 3.
24 waves of 72 to 4.18 GHz center frequency 970 to 1430 M
It is converted into 24 waves of Hz, and the tuner 8 tunes to one of the waves. The output of the tuner 8 has an IF frequency of 510 MHz and the band is, for example, 25 MHz. Reference numeral 9 is a video intermediate wave amplifier circuit (hereinafter referred to as IF circuit), which is a band pass wave filter (BPF).
Is included. Reference numeral 10 is a wideband FM detection circuit, for example, PLL detection is used. Reference numeral 11 is a voice detection circuit for performing FM detection on the voice carrier being output from the FM detection circuit 10. The voice signal processing circuit 13 converts the output of the voice detection circuit 11 into an appropriate level and frequency characteristic, and outputs the RF signal. The output of the audio signal processing circuit 13 is supplied to the converter 14. On the other hand, the video signal processing circuit 12 removes the high frequency component of 4.2 MHz or more and the energy diffusion signal, outputs the signal at an appropriate level, and supplies the output of the video signal processing circuit 12 to the RF converter 14. Reference numeral 15 is an automatic polarization control circuit which changes the plane of polarization and stops it at the optimum point.
自動偏波制御回路１５の１例を第４図に示す。先ず希望
波をＮチャンネルとする。送られて来る信号（Ｎ−
１），Ｎ，（Ｎ＋１）のスペクトルはＩＦ帯で考える
時、第５図(A)の如く等しいレベルとする。この場合、
（Ｎ−１）チャンネルの中心が４９０MHz，（Ｎ＋１）
チャンネルの中心が５３０MHzになるものとする。偏波
器２の偏波面が、垂直と水平のほゞ中間にある時、信号
が第５図(B)の如き帯域通過波器を通ると、ＩＦ回路
９の出力は第５図(C)の如くになる。Ｎチャンネルの信
号が垂直偏波とすると、偏波器２の偏波面が垂直になる
と、第５図(A)の点線の如く、隣接チャンネルの信号は
約１５dB低下する。（偏波器の分離度を１５dBとした
時）従って、帯域通過波器を通ると、第５図(D)の如
きスペクトルとなる。An example of the automatic polarization control circuit 15 is shown in FIG. First, the desired wave is set to N channel. Signal sent (N-
The spectra of 1), N, and (N + 1) have the same level as shown in FIG. 5 (A) when considered in the IF band. in this case,
Center of (N-1) channel is 490 MHz, (N + 1)
The center of the channel shall be 530MHz. When the plane of polarization of the polarizer 2 is approximately in the middle between the vertical and horizontal directions, and the signal passes through a bandpass wave filter as shown in Fig. 5 (B), the output of the IF circuit 9 is shown in Fig. 5 (C). It becomes like. If the N-channel signal is vertically polarized and the plane of polarization of the polarizer 2 is vertical, the signal of the adjacent channel is reduced by about 15 dB as indicated by the dotted line in FIG. 5 (A). (When the degree of separation of the polarizer is set to 15 dB) Therefore, when passing through the band pass wave filter, a spectrum as shown in Fig. 5 (D) is obtained.
以上の説明では、通常のテレビ信号のＦＭの周波数変移
が平均して約１０MHz程度と考えてスペクトルを図示し
てある。以下の各図においても同様である。一方、偏波
器２の偏波面と、第３図１６のＡＧＣ検波回路の出力の
関係は第７図(A)の実線で示される。ＡＧＣ検波回路１
６は、ＩＦ回路９の出力に比例したＤＣ電圧を発生さ
せ、チューナー８のＩＦ回路９を利得制御し、ＩＦ回路
９の入力、出力を一定に保つ。即ち、ＩＦ回路９にはＡ
ＧＣをかけない。従って、偏波面が垂直になって、信号
振幅が最大となる時、ＡＧＣ検波回路１６の出力は最大
となる。即ち、基準点０度から、水平方向に−４５度以
上偏波器２の偏波面（ポラローターの時はプローブ）を
まわした点、即ち第７図のＳＴから、偏波面を変化さ
せ、水平（−４５度），０度，垂直（＋４５度）と変化
し、垂直より更に行過ぎた点第７図ＥＮＤで、１回の偏
波面の掃引が終るものとすると、理想的な動作状態では
第７図(A)の実線の如く変化する。同様に、水平偏波の
信号を受信する時の偏波面の角度とＡＧＣ検波回路１６
の出力の関係は第７図(A)の点線となる。第７図(A)の点
線或は実線の関係が得られるのは理想的な状態である
が、この時の動作を第４図，第７図(A)と共に述べる。
希望波がＮチャンネルとすると、チャンネルＮを指定す
ると、３入力ＮＯＲゲート２１の出力は低レベルとなっ
て、フリップフロップ２０をセットし、そのＱ出力が高
レベルとなって、スイープ電圧発生回路１９から、鋸歯
状波電圧又は三角波を発生させる。一方、３入力ＮＯＲ
ゲート２１の出力はピークホールド回路１７へ伝えら
れ、ホールドされている電圧を放電する。スイープ電圧
発生回路１９の出力電圧の変化に伴い偏波器２の偏波面
が変化する。偏波器２として、フェロフィールドと呼ば
れる形式のものを使う時は、スイープ電圧を増幅して用
いる。ポラロータと呼ばれる形式のものはパルス幅に比
較して偏波面の回転角が決まるので、スイープ電圧をパ
ルスゼネレータ２２でパルス幅に変換して、偏波器２へ
供給する。ここではポラロータを考える。第７図(A)の
ＳＴから偏波面を変化させ、＋４５度で、ＡＧＣ電圧が
最大値になったとすると、このピーク電圧ＰＶをピーク
ホールド回路１７でピークホールドする。スイープ電圧
はＥＮＤに達すると再びＳＴから同じ変化をする。この
時、レベル比較器１８で、ＡＧＣ検波回路１６の出力と
ピークホールド回路１７の出力を比較し、一致した時負
パルスを出力し、フリップフロップ２０をリセットす
る。フリップフロップ２０のＱ出力が低レベルになっ
て、スイープ電圧発生回路１９のスイープ電圧は発生し
なくなり、かつ、偏波器のロータをまわすＤＣパワーも
ＤＣ電圧供給回路２３から供給されなくなる。（ＤＣ電
圧供給回路２３はフリップフロップ２０のＱ出力が高レ
ベルの間のみ偏波器２へＤＣパワーを供給する）従っ
て、ポラロータの偏波面は、最適位置の＋４５度で停止
する。次に、希望波が隣接ＣＨより４〜５dB弱い場合を
考える。（現実にこういう状態がアメリカでは発生して
いる。）偏波器の偏波面が水平，垂直の中間にある時、
或は偏波器２が無い時、チューナー８の出力側で、第６
図(D)の如きスペクトルとなる。この時、前の状態の偏
波面が水平で、今度が垂直だとすると、偏波器の偏波面
変化が始まらない時は、チューナー８の出力は第６図
(A)の如くであり、帯域通過波器を通った後でも第６
図(D)の如きスペクトルとなる。このような状態の時、
偏波面をＳＴから変化させ始めると、第７図(B)の一点
鎖線の如くＰＨ′がピークになって、ＰＶ′より高くな
ったり、ＰＶ′の方がＰＨ′より高くても、正規のＰＶ
より手前でピークになる事が有る。この時は、チューナ
ー８の出力は第６図(C)の如くなる。隣接波の影響が少
ない時は、第７図(B)の実線又は破線となり第７図(A)の
場合と同じように最適偏波面が決められる。電源ＯＮ時
及び手動でスイープ開始を指示した時も、前述の如く動
作する。In the above description, the spectrum is illustrated assuming that the frequency shift of the FM of a normal television signal is about 10 MHz on average. The same applies to the following figures. On the other hand, the relationship between the polarization plane of the polarizer 2 and the output of the AGC detection circuit of FIG. 3 is shown by the solid line in FIG. 7 (A). AGC detection circuit 1
6 generates a DC voltage proportional to the output of the IF circuit 9, controls the gain of the IF circuit 9 of the tuner 8, and keeps the input and output of the IF circuit 9 constant. That is, the IF circuit 9 has A
Do not apply GC. Therefore, when the plane of polarization becomes vertical and the signal amplitude becomes maximum, the output of the AGC detection circuit 16 becomes maximum. That is, from the reference point 0 degrees, the polarization plane of the polarizer 2 (probe in the case of a polar rotor) is rotated horizontally by -45 degrees or more from the reference point, that is, from the ST of FIG. It changes from (-45 degrees), 0 degrees, to vertical (+45 degrees), and when it goes beyond the vertical, at point END in FIG. 7, assuming that one sweep of the polarization plane ends, in an ideal operating state It changes as shown by the solid line in Fig. 7 (A). Similarly, when the horizontal polarization signal is received, the angle of the polarization plane and the AGC detection circuit 16
The output relationship is shown by the dotted line in Fig. 7 (A). It is in an ideal state that the relationship between the dotted line and the solid line in FIG. 7 (A) is obtained. The operation at this time will be described with reference to FIGS. 4 and 7 (A).
When the desired wave is the N channel, when the channel N is designated, the output of the 3-input NOR gate 21 becomes low level, sets the flip-flop 20, and its Q output becomes high level, and the sweep voltage generating circuit 19 To generate a sawtooth voltage or a triangular wave. On the other hand, 3-input NOR
The output of the gate 21 is transmitted to the peak hold circuit 17, and the held voltage is discharged. The polarization plane of the polarizer 2 changes as the output voltage of the sweep voltage generating circuit 19 changes. When using a type called a ferrofield as the polarizer 2, a sweep voltage is amplified and used. Since the rotation angle of the plane of polarization is determined in comparison with the pulse width in the type called polara, the sweep voltage is converted into the pulse width by the pulse generator 22 and supplied to the polarizer 2. Here we consider a polarota. Changing the polarization from the ST of FIG. 7 (A), at + 45 degrees, the AGC voltage and reaches the maximum value, the peak-hold the peak voltage P V peak-hold circuit 17. When the sweep voltage reaches END, it changes from ST again. At this time, the level comparator 18 compares the output of the AGC detection circuit 16 with the output of the peak hold circuit 17, outputs a negative pulse when they match, and resets the flip-flop 20. The Q output of the flip-flop 20 becomes a low level, the sweep voltage of the sweep voltage generating circuit 19 is not generated, and the DC power for rotating the rotor of the polarizer is also not supplied from the DC voltage supply circuit 23. (The DC voltage supply circuit 23 supplies DC power to the polarizer 2 only while the Q output of the flip-flop 20 is at a high level.) Therefore, the polarization plane of the polar rotor stops at +45 degrees which is the optimum position. Next, consider a case where the desired wave is 4 to 5 dB weaker than the adjacent CH. (In reality, such a situation occurs in the United States.) When the polarization plane of the polarizer is in the middle between horizontal and vertical,
Or when there is no polarizer 2, the output side of the tuner 8
The spectrum is as shown in Figure (D). At this time, assuming that the polarization plane in the previous state is horizontal and this time it is vertical, the output of the tuner 8 is output when the polarization plane of the polarizer does not start to change.
It is like (A), and even after passing through the bandpass wave
The spectrum is as shown in Figure (D). In this situation,
And begins to change the polarization from ST, 'it becomes peak, P V' P H as a dashed line Figure 7 (B) or higher than, and P V 'towards the P H' higher than Also a regular PV
It may peak before this. At this time, the output of the tuner 8 is as shown in FIG. 6 (C). When the influence of adjacent waves is small, the solid or broken line in FIG. 7 (B) results and the optimum plane of polarization is determined as in the case of FIG. 7 (A). Even when the power is turned on or when the sweep start is manually instructed, the operation is performed as described above.
なお、いわゆる地上波妨害が、５００MHz，５２０MHz付
近にあれば、その影響１２より第７図のＰＨ，ＰＶ以外
の点でＡＧＣ電圧が最大ととなり最適偏波面を設定でき
ない。Incidentally, so-called ground wave interference, 500 MHz, if in the vicinity of 520 MHz, P H of Figure 7 from its effects 12, AGC voltage at a point other than P V can not set up a next optimum polarization.
発明が解決しようとする問題点 しかしながら上記した構成では、電波の強弱，妨害波等
のため、以下のような誤動作する事が多いという問題点
を有していた。Problems to be Solved by the Invention However, the above-described configuration has a problem in that the following malfunctions often occur due to the strength and weakness of radio waves, interfering waves, and the like.
(1)隣接チャンネル信号の影響による誤動作。(1) Malfunction due to the influence of adjacent channel signal.
(2)隣接チャンネルと希望波信号の入力差による誤動
作。(2) Malfunction due to input difference between adjacent channel and desired wave signal.
(3)地上波妨害による誤動作。(3) Malfunction due to ground wave interference.
本発明は上記した問題点に鑑み、上記の各誤動作を起こ
さない衛星放送受信機の偏波器制御回路を提供すること
を目的とする。In view of the above problems, it is an object of the present invention to provide a polariser control circuit for a satellite broadcast receiver that does not cause each of the above malfunctions.
問題点を解決するための手段 本発明は上記した問題点を解決するもので、偏波面を選
ぶ偏波器を最適な状態に設定する偏波面制御回路と、前
記偏波面制御回路へ前記偏波器の偏波面が最適状態であ
ることを示す制御信号を供給する偏波器の偏波面の状態
判別回路とを設け、前記偏波器を制御し、偏波面を変化
させている間のみ映像信号中間周波増幅回路段の帯域
波器の通過帯域幅を通常動作状態に比べ狭帯域とした構
成となっている。Means for Solving the Problems The present invention is to solve the above-mentioned problems, and a polarization plane control circuit that sets a polarizer that selects a polarization plane in an optimum state, and the polarization plane control circuit is provided with the polarization plane control circuit. A polarization state determination circuit for the polarization plane that supplies a control signal indicating that the polarization plane is in the optimum state is provided, and the video signal is controlled only while controlling the polarization plane and changing the polarization plane. The pass band width of the band pass filter in the intermediate frequency amplifier circuit stage is narrower than that in the normal operation state.
作用 本発明は上記した構成により帯域波器を２段直列と
し、偏波器の偏波面を制御している間のみ、リレーを動
作させ、波器を２段直列とし、隣接キャリアを減衰さ
せ、誤動作を除くものである。Action The present invention has two stages of band wave filters in series with the above configuration, operates the relay only while controlling the polarization plane of the polarizer, sets the wave filters in two stages in series, and attenuates adjacent carriers. This excludes malfunctions.
実施例 以下、本発明の実施例につき図面を参照しながら説明す
る。第１図は本発明の一実施例における衛星放送受信機
の偏波面制御回路の回路ブロック図を示すものである。
尚、図中第４図と同一部は同一番号を付し、従来例と同
一の動作をするので説明は省く。Embodiments Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram of a polarization plane control circuit of a satellite broadcast receiver according to an embodiment of the present invention.
In the figure, the same parts as those in FIG.
第１図において、９１は第２図(A)の特性で、第５図
(B)，第６図(B)と同じ特性の第１帯域通過波器(B.P.
F)、９２は第２図(B)の特性の第２帯域通過波器(B.P.
F)でB.P.F９１より狭い帯域になっている。２４Ｓは偏
波器２に電力が供給されている間のみ、端子ａ−ｃ間が
短絡となるスイッチで、２４Ｌはリレーのコイルであ
り、ＤＣ電圧供給回路２３の出力が存在する時、スイッ
チ２４Ｓの端子ａ−ｃ間を短絡させる。９Ａは映像中間
周波増幅回路（以下ＩＦ回路という）である。B.P.F９
１の出力は第２図(A)の実線で示す出力であり、B.P.F９
２の出力は、第２図(A),(B)の実線を重ね合わせた特性
の出力となる。受信希望波がＮチャンネルで偏波面が垂
直で、（Ｎ−１），（Ｎ＋１）チャンネルより５dB弱い
信号とし、直前に受信していたチャンネルが水平偏波で
あったとする。受信チャンネルをＮチャンネルに指定し
た直後、チューナー８の出力で考えると、第２図(C)の
如きスペクトルとなり、希望波のピークＰ1は、隣接チ
ャンネルのピークＰ0，Ｐ2より２０dB低い。しかし、B.
P.F９２の出力では、Ｐ0，Ｐ2はＰ1に対し、約４０dB減
衰し、第２図(D)の如く、希望波のＰ1レベルはＰ0，Ｐ2
より２０dB高くなる。もし希望波と隣接チャンネルが同
一の信号レベルであれば、Ｐ1はＰ0，Ｐ2よりB.P.F９２
の出力では２５dB高くなる。この状態で、第７図のＳＴ
からスイープ電圧発生回路１９のスイープ電圧を変化さ
せ、偏波器２の偏波面を変化させると、第７図(A)の実
線の如きＡＧＣ電圧の変化が得られ、垂直偏波面の位置
即ち＋４５度で偏波器２の偏波面が停止し、正しく偏波
面の設定ができる。偏波面が正しく設定されると、ＤＣ
電圧供給回路２３のＤＣ出力パワーが無くなり、リレー
２４Ｌに電流が流れなくなり、スイッチ２４Ｓの端子ｂ
−ｃ間は短絡となり、ＩＦ回路９ＡへはB.P.F９１の出
力が伝わる。この時、B.P.F９１の出力は第５図(D)の如
く、希望波が隣接チャンネルより２０dB以上高いレベル
となる。第５図(D)では、希望波が隣接チャンネルと同
一レベルの場合を示し、希望波が隣接チャンネルよりB.
P.F９１の出力で３０dB強くなっているが、希望波が隣
接チャンネルより５dB弱くても、B.P.F９１の出力で希
望波が、隣接チャンネルより２５dB強くなる事は、第５
図(A),(B),(D)より明らかである。電源ＯＮ時及び手動
スイッチで偏波面をスイープさせる場合も同じ動作をす
る事は明らかである。In FIG. 1, 91 is the characteristic of FIG. 2 (A), and FIG.
(B), 1st band pass wave device (BP
F) and 92 are second band pass wave filters (BP) having the characteristics shown in FIG. 2 (B).
F) has a narrower band than BPF91. 24S is a switch that short-circuits terminals a and c only while power is being supplied to the polarizer 2, 24L is a coil of a relay, and when the output of the DC voltage supply circuit 23 is present, the switch 24S The terminals a and c are short-circuited. Reference numeral 9A is a video intermediate frequency amplifier circuit (hereinafter referred to as IF circuit). BPF9
The output of 1 is the output shown by the solid line in FIG.
The output of 2 is the output of the characteristic in which the solid lines in FIGS. 2 (A) and 2 (B) are superimposed. It is assumed that the desired wave to be received is the N channel, the plane of polarization is vertical, and the signal is 5 dB weaker than the (N-1) and (N + 1) channels, and the channel received immediately before is the horizontal polarization. When the output of the tuner 8 is considered immediately after the reception channel is designated as the N channel, the spectrum is as shown in FIG. 2 (C), and the peak P 1 of the desired wave is 20 dB lower than the peaks P 0 and P 2 of the adjacent channels. But B.
At the output of P.F92, P 0 and P 2 are attenuated by about 40 dB with respect to P 1 , and the P 1 level of the desired wave is P 0 and P 2 as shown in FIG. 2 (D).
20 dB higher than that. If the desired wave and the adjacent channel have the same signal level, P 1 is calculated from P 0 and P 2 by the BPF 92.
The output is 25 dB higher. In this state, ST of FIG.
When the sweep voltage of the sweep voltage generating circuit 19 is changed to change the polarization plane of the polarizer 2, a change in the AGC voltage as shown by the solid line in FIG. 7 (A) is obtained, and the position of the vertical polarization plane, that is, +45. After that, the polarization plane of the polarizer 2 stops, and the polarization plane can be set correctly. When the plane of polarization is set correctly, DC
The DC output power of the voltage supply circuit 23 disappears, the current stops flowing through the relay 24L, and the terminal b of the switch 24S.
A short circuit occurs between −c and the output of the BPF 91 is transmitted to the IF circuit 9A. At this time, the output of the BPF 91 becomes a level in which the desired wave is higher than the adjacent channel by 20 dB or more, as shown in FIG. 5 (D). FIG. 5 (D) shows the case where the desired wave is at the same level as the adjacent channel, and the desired wave is B.
The output of P.F91 is 30 dB stronger, but even if the desired wave is 5 dB weaker than the adjacent channel, the desired wave is 25 dB stronger than the adjacent channel at the output of BPF91.
It is clear from Figures (A), (B) and (D). It is clear that the same operation is performed when the power is turned on and when the plane of polarization is swept by the manual switch.
以上の説明では偏波器２の偏波面が希望波の偏波面と逆
の状態から始まる場合を述べたが、偏波器２の偏波面と
希望波の偏波面が一致した状態、即ちチューナー８の出
力が第５図(C)のようなスペクトル関係で始まっても、
偏波器２の偏波面を変化させれば、第２図(C)のような
状態がある。しかし、いずれの場合も第２図(B)に示す
特性のフィルターにより、ＡＧＣ検波回路１６の入力は
偏波面切替中は、希望波が隣接波より十分高いレベルで
あるので、第７図(A)の実線又は破線の関係が得られ偏
波器２の偏波面は希望波の偏波面と一致する。In the above description, the case where the polarization plane of the polarizer 2 starts in a state opposite to the polarization plane of the desired wave has been described. However, the polarization plane of the polarizer 2 and the polarization plane of the desired wave match, that is, the tuner 8 Even if the output of starts with the spectrum relationship as shown in Fig. 5 (C),
If the plane of polarization of the polarizer 2 is changed, there will be a state as shown in FIG. However, in either case, the desired wave is at a sufficiently higher level than the adjacent wave while the polarization plane is being switched at the input of the AGC detection circuit 16 by the filter having the characteristics shown in FIG. The relationship of the solid line or the broken line is obtained, and the polarization plane of the polarizer 2 matches the polarization plane of the desired wave.
ＡＧＣ検波回路１６の出力をチューナー８のＩＦ回路９
Ａへ加えて、利得の調整を行なうので、偏波面設定用の
別の検波回路は不要である。The output of the AGC detection circuit 16 is fed to the IF circuit 9 of the tuner 8.
Since the gain is adjusted in addition to A, another detection circuit for setting the polarization plane is unnecessary.
発明の効果 以上のように本発明によれば以下の優れた効果を奏する
ことができる。EFFECTS OF THE INVENTION As described above, according to the present invention, the following excellent effects can be achieved.
(1)偏波器を設定する短い時間のみ帯域波器の帯域を
狭くするので、偏波器設定終了後は、良好な映像信号を
得る事ができる為に適当な帯域に戻る。(1) Band The band of the wave filter is narrowed only for a short time when the polarizer is set. Therefore, after the polarization setting is completed, a good video signal can be obtained and the band returns to an appropriate band.
(2)隣接チャンネルの信号が希望波より５dB程度強くて
も、その影響を受けず偏波面の設定ができる。(2) Even if the signal of the adjacent channel is about 5 dB stronger than the desired wave, the plane of polarization can be set without being affected by it.
(3)帯域通過特性から明らかな如く、５２０MHz，５００
MHzに地上波妨害があっても、約５dB軽減した状態で、
偏波面の設定が行えるので、誤動作が軽減される。(3) As is clear from the bandpass characteristics, 520MHz, 500
Even if there is ground wave interference at MHz, with about 5 dB reduced,
Since the plane of polarization can be set, malfunctions are reduced.
(4)ＡＧＣ検波の入力信号の帯域が、偏波面設定時以外
はＦＭ検波の入力信号と同一であり、周波数変移の大き
な信号に対しても、正しいＡＧＣ電圧を出力し得る。(4) The band of the input signal for AGC detection is the same as the input signal for FM detection except when the polarization plane is set, and a correct AGC voltage can be output even for a signal with a large frequency shift.
第１図は本発明の一実施例における衛星放送受信機の偏
波器制御回路のブロック図、第２図は同帯域通過波器
の特性図、第３図は従来の衛星放送受信機のブロック
図、第４図は同偏波器制御回路のブロック図、第５図，
第６図は同動作説明のための特性図、第７図は同ＡＧＣ
電圧と偏波面の関係を示す特性図である。 ２……偏波器、８……チューナー、９Ａ……中間周波増
幅回路、１０……ＦＭ検波回路、１６……ＡＧＣ検波回
路、１７……ピークホールド回路、１８……レベル比較
器、１９……スイープ電圧発生回路、２０……フリップ
フロップ、２１……３入力ＮＯＲゲート、２２……パル
ス発生器、２３……ＤＣ電圧供給回路、９１……第１帯
域通過波器、９２……第２帯域通過波器。FIG. 1 is a block diagram of a polariser control circuit of a satellite broadcast receiver in one embodiment of the present invention, FIG. 2 is a characteristic diagram of the same band pass wave device, and FIG. 3 is a block of a conventional satellite broadcast receiver. Fig. 4 is a block diagram of the same polariser control circuit, Fig. 5,
FIG. 6 is a characteristic diagram for explaining the same operation, and FIG. 7 is the same AGC.
It is a characteristic view which shows the relationship between a voltage and a polarization plane. 2 ... Polarizer, 8 ... Tuner, 9A ... Intermediate frequency amplification circuit, 10 ... FM detection circuit, 16 ... AGC detection circuit, 17 ... Peak hold circuit, 18 ... Level comparator, 19 ... ... Sweep voltage generation circuit, 20 ... Flip-flop, 21 ... 3-input NOR gate, 22 ... Pulse generator, 23 ... DC voltage supply circuit, 91 ... First band pass wave generator, 92 ... Second Bandpass wave device.
Claims (1)
有し、テレビジョン映像信号により周波数変調された高
周波信号を受信する衛星放送受信機の偏波器制御回路に
おいて、 偏波面を変化させて前記２種類の偏波面のいずれか一方
の偏波面の信号のみを選択する偏波器と、前記偏波器の
偏波面が変化している間のみ映像中間周波増幅段の帯域
通過ろ波器の通過帯域幅を中心から約±１０MHz離れた
点で、通常動作時の通過特性より約１０dB減衰した狭帯
域にする、直列に接続された第１の帯域ろ波器と第２の
帯域ろ波器と、前記第１の帯域ろ波器の出力と前記第２
の帯域ろ波器の出力とを切り換えて出力する切換手段
と、前記切換手段の出力を入力する映像中間周波増幅回
路と、前記映像中間周波増幅回路の出力を検波するＡＧ
Ｃ検波回路と、前記ＡＧＣ検波回路の出力電圧のピーク
値を保持するピークホールド回路と、前記ＡＧＣ検波回
路の出力と前記ピークホールド回路の保持電圧とを比較
するレベル比較回路とを備え、前記偏波器の偏波面が変
化しているときは前記切換手段は前記第２の帯域ろ波器
からの出力を前記映像中間周波増幅回路に出力し、また
前記レベル比較器によって前記ＡＧＣ検波回路の出力と
前記ピークホールド回路の出力が等しいと判断され前記
偏波器の偏波面が固定されたときは前記切換手段は前記
第１の帯域ろ波器からの出力を前記映像中間周波増幅回
路に出力することを特徴とする衛星放送受信機の偏波器
制御回路。Claim: What is claimed is: 1. A polarization control circuit of a satellite broadcasting receiver, which has two types of polarization planes transmitted from a satellite and receives a high frequency signal frequency-modulated by a television video signal. And a polarizer that selects only a signal of one of the two polarization planes, and a band-pass filter of the video intermediate frequency amplification stage only while the polarization plane of the polarizer is changing. The first bandpass filter and the second bandpass filter connected in series make the pass band width of the filter about ± 10MHz away from the center, and make it a narrow band that is attenuated by about 10dB from the pass characteristic during normal operation. Wave filter, the output of the first bandpass filter and the second band filter
Switching means for switching and outputting the output of the band-pass filter, a video intermediate frequency amplifier circuit for inputting the output of the switching means, and an AG for detecting the output of the video intermediate frequency amplifier circuit.
A C detection circuit, a peak hold circuit that holds the peak value of the output voltage of the AGC detection circuit, and a level comparison circuit that compares the output of the AGC detection circuit and the held voltage of the peak hold circuit. When the polarization plane of the wave filter is changing, the switching means outputs the output from the second bandpass filter to the video intermediate frequency amplifying circuit, and the level comparator outputs the output of the AGC detecting circuit. And the output of the peak hold circuit is determined to be equal, and the polarization plane of the polarizer is fixed, the switching means outputs the output from the first bandpass filter to the video intermediate frequency amplifier circuit. Polarizer control circuit for satellite broadcasting receiver characterized by the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21821185A JPH0659101B2 (en) | 1985-10-01 | 1985-10-01 | Polarizer control circuit for satellite receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21821185A JPH0659101B2 (en) | 1985-10-01 | 1985-10-01 | Polarizer control circuit for satellite receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6277786A JPS6277786A (en) | 1987-04-09 |
| JPH0659101B2 true JPH0659101B2 (en) | 1994-08-03 |
Family
ID=16716361
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21821185A Expired - Lifetime JPH0659101B2 (en) | 1985-10-01 | 1985-10-01 | Polarizer control circuit for satellite receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0659101B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06105974B2 (en) * | 1985-11-15 | 1994-12-21 | 松下電器産業株式会社 | Polarizer control device |
| JP2508461B2 (en) * | 1986-07-14 | 1996-06-19 | ソニー株式会社 | Satellite receiver |
| JPH0197609U (en) * | 1987-12-19 | 1989-06-29 | ||
| JPH0289485A (en) * | 1988-09-27 | 1990-03-29 | Fujitsu General Ltd | satellite broadcast receiver |
| JP2809658B2 (en) * | 1988-12-27 | 1998-10-15 | 三菱電機株式会社 | Satellite line polarization setting device |
-
1985
- 1985-10-01 JP JP21821185A patent/JPH0659101B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6277786A (en) | 1987-04-09 |
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