JPH0125447B2 - - Google Patents
Info
- Publication number
- JPH0125447B2 JPH0125447B2 JP56130454A JP13045481A JPH0125447B2 JP H0125447 B2 JPH0125447 B2 JP H0125447B2 JP 56130454 A JP56130454 A JP 56130454A JP 13045481 A JP13045481 A JP 13045481A JP H0125447 B2 JPH0125447 B2 JP H0125447B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- voltage
- search
- circuit
- channel
- 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
Links
- 238000001514 detection method Methods 0.000 claims description 37
- 230000003321 amplification Effects 0.000 claims description 11
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 2
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 3
- 230000001960 triggered effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J1/00—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
- H03J1/0008—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor
- H03J1/0091—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor provided with means for scanning over a band of frequencies
Landscapes
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
Description
【発明の詳細な説明】
この発明はテレビジヨン受像機の探局装置の改
良に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a station searching device for a television receiver.
まず従来の探局装置を第１図により説明する。
図において、１１は電子チユーナ、１２は映像中
間周波フイルタ、１３は映像中間周波増幅回路、
１４は映像検波回路、１５はAFT検波回路、１
６は同期分離回路、１７はテレビ信号判別検出回
路、１８はAFT―UP，DOWN信号発生回路、
１９はAFTコントロール回路、２０はプリセツ
トコントロール回路、２１はチユーニングクロツ
クジエネレータ回路、２２はインフオメーシヨン
カウンタ、２３はアドレス入力コントロール回
路、２４は同調電圧記憶回路、２５はＤ／Ａ（デ
ジタル―アナログ）コンバータ回路、２６は同調
電圧積分回路である。またａは映像中間周波信
号、ｂはAFT検波出力、ｃは映像検波出力、ｄ
はAFT―UP信号、ｅはAFT―DOWN信号、ｆ
は同期信号、ｇは受像機のフライバツク信号、ｈ
はテレビ信号判別信号、h′はAFT信号、ｋはア
ドレス信号、ｌはチユーナ同調電圧信号、ｍはチ
ユーナ同調電圧、ｉは探局トリガ信号、ｊは探
局、通常モード切替信号、２７は探局トリガスイ
ツチ、２８は探局、通常モード切替スイツチであ
る。 First, a conventional station searching device will be explained with reference to FIG.
In the figure, 11 is an electronic tuner, 12 is a video intermediate frequency filter, 13 is a video intermediate frequency amplification circuit,
14 is a video detection circuit, 15 is an AFT detection circuit, 1
6 is a synchronization separation circuit, 17 is a TV signal discrimination detection circuit, 18 is an AFT-UP, DOWN signal generation circuit,
19 is an AFT control circuit, 20 is a preset control circuit, 21 is a tuning clock generator circuit, 22 is an information counter, 23 is an address input control circuit, 24 is a tuning voltage storage circuit, and 25 is a D/A ( 26 is a tuned voltage integration circuit. Also, a is the video intermediate frequency signal, b is the AFT detection output, c is the video detection output, and d
is AFT-UP signal, e is AFT-DOWN signal, f
is the synchronization signal, g is the flyback signal of the receiver, h
is a television signal discrimination signal, h' is an AFT signal, k is an address signal, l is a tuner tuning voltage signal, m is a tuner tuning voltage, i is a search trigger signal, j is a search station, normal mode switching signal, and 27 is a search signal. The station trigger switch 28 is a station search/normal mode changeover switch.
さて、切替スイツチ２８が探局モード（ｊ＝＋
Ｂ）の時、VHF―LOWバンドでしかも電子チユ
ーナ１１が最低の同調電圧で受信できるテレビ信
号がアンテナより入力され、同時にアドレス信号
ｋがアドレス入力コントロール回路２３に加わつ
てあるアドレスを選局している状態にあつて、探
局トリガスイツチ２７を押すと、ｉ＝＋Ｂのトリ
ガパルスがプリセツトコントロール回路２０に加
わり、チユーニングクロツクジエネレータ回路２
１のクロツクをスタートさせ、Ｄ／Ａコンバータ
回路２５の出力ｌを上昇させる。この出力ｌは同
調電圧積分回路２６で積分されて電子チユーナ１
１に加わり、チユーナ同調電圧ｍがテレビ信号の
同調電圧になつた時映像中間周波信号ａを得る。
この信号ａは映像中間周波フイルタ１２を経由し
映像中間周波増幅回路１３で増幅され、一方は
AFT検波回路１５に入力されてAFT検波出力ｂ
を出力し、他方は映像検波回路１４に入力されて
映像検波出力ｃを出力し、さらに同期分離回路１
６を経て同期信号ｆとなりテレビ信号判別検出回
路１７に入力されてフライバツク信号ｇとアンド
ゲートされ、テレビ信号判別信号ｈを出力する。
またAFT検波出力ｂはAFT―UP，DOWN信号
発生回路１８であらかじめ設定された電圧VH，
VLと比較され、ｂ≧VHの時、AFT―UP信号ｄ
＝LOW（以下Ｌと略す）、AFT―DOWN信号ｅ
＝High（以下Ｈと略す）を出力し、ｂ≦VLの時、
ｄ＝Ｈ，ｅ＝Ｌを出力する。AFTコントロール
回路１９には出力ｄ，ｅ，ｈが入力され、同調電
圧ｍを上昇させてテレビ信号を捕えた時は一般
に、AFT検波出力ｂは、VL＜ｂ＜VH→ｂ＞VH→
VL＜ｂ＜VH→ｂ＜VL→VL＜ｂ＜VHの順序で変化
する。これに伴つてAFT―UP信号ｄは、Ｈ→Ｌ
→Ｈ→Ｈとなり、AFT―DOWN信号ｅは、Ｈ→
Ｈ→Ｌ→Ｈと変化し、またｈは、Ｌ→Ｈ→Ｈ→Ｌ
と変化し、AFTコントロール回路１９で出力ｄ
とｈ，ｅとｈがアンドゲートされてプリセツトコ
ントロール回路２０に入力され、ここで信号ｄが
Ｌ→Ｈに変化した時の同調電圧信号ｌと信号ｅが
Ｈ→Ｌに変化した時の同調電圧信号ｌから最適同
調電圧を計算し、チユーニングクロツクジエネレ
ータ回路２１の上昇動作を停止して最適同調点に
設定し最終的に信号ｌを積分して電子チユーナ１
１に加え、最適同調点の映像中間周波信号ａを得
る。 Now, the changeover switch 28 is set to the search mode (j=+
At the time of B), a TV signal in the VHF-LOW band that the electronic tuner 11 can receive at the lowest tuning voltage is input from the antenna, and at the same time, the address signal k is applied to the address input control circuit 23 to tune a certain address. When the search trigger switch 27 is pressed in this state, a trigger pulse of i=+B is applied to the preset control circuit 20, and the tuning clock generator circuit 2
1 clock is started, and the output l of the D/A converter circuit 25 is increased. This output l is integrated by the tuning voltage integration circuit 26 and is then integrated into the electronic tuner 1.
1, and when the tuner tuning voltage m becomes the tuning voltage of the television signal, a video intermediate frequency signal a is obtained.
This signal a passes through a video intermediate frequency filter 12 and is amplified by a video intermediate frequency amplification circuit 13;
Input to AFT detection circuit 15 and AFT detection output b
The other is input to the video detection circuit 14 to output the video detection output c, and the synchronous separation circuit 1
6, it becomes a synchronizing signal f, which is input to a television signal discrimination and detection circuit 17, where it is AND gated with a flyback signal g, and outputs a television signal discrimination signal h.
In addition, the AFT detection output b is a voltage V H , which is set in advance by the AFT-UP, DOWN signal generation circuit 18.
When compared with V L , when b≧V H , AFT-UP signal d
= LOW (hereinafter abbreviated as L), AFT-DOWN signal e
=High (hereinafter abbreviated as H) is output, and when b≦V L ,
Output d=H, e=L. Outputs d, e, and h are input to the AFT control circuit 19, and when the tuning voltage m is increased to capture a television signal, the AFT detection output b is generally V L <b<V H →b>V H →
It changes in the order of V L < b < V H → b < V L → V L < b < V H. Along with this, the AFT-UP signal d changes from H to L.
→H→H, AFT-DOWN signal e is H→
Changes from H→L→H, and h changes from L→H→H→L
The AFT control circuit 19 outputs d.
and h, e and h are AND gated and input to the preset control circuit 20, where the tuning voltage signal l when the signal d changes from L to H and the tuning voltage signal l when the signal e changes from H to L The optimum tuning voltage is calculated from the voltage signal l, the rising operation of the tuning clock generator circuit 21 is stopped, the optimum tuning point is set, and the signal l is finally integrated to tune the electronic tuner 1.
In addition to 1, a video intermediate frequency signal a at the optimum tuning point is obtained.
このように探局動作はテレビ信号を捕える度に
停止するので、次に探局動作を開始する時は探局
トリガスイツチ２７をオンにし、ｉ＝＋Ｂとして
以下テレビ信号を捕えるまで同調電圧ｍを上昇さ
せる。テレビ信号を捕えた時の動作は前述の通り
であり、さらにその都度探局トリガスイツチ２７
をオンにしてｉ＝＋Ｂとするトリガ入力を加える
と、同調電圧ｍはUHFバンドの最大電圧まで上
昇した後停止する機能になつており、これによつ
て探局動作は停止しつぎに同調電圧信号ｌを
VHF―LOWバンドの最低チヤンネル用の最小電
圧に設定して、プリセツトコントロール回路２０
は探局動作からフアインチユーニングの動作に入
るようになる。すなわち、AFTコントロール回
路１９およびプリセツトコントロール回路２０の
動作は探局動作とフアインチユーニング動作の２
つに分れ、探局動作中の時はｄ＝Ｌ，ｅ＝Ｈ→ｄ
＝Ｈ，ｅ＝ＬでAFT情報が変化し、この変化の
期間中ｈ＝Ｈであれば、前記回路１９，２０はこ
のAFT情報ｄ，ｅを有効として探局動作を停止
し、フアインチユーニング動作に移る。またこれ
以外のｄ，ｅ，ｈの信号の関係であればAFT情
報ｄ，ｅを無効として探局動作を続け、結果とし
て信号ｌを上昇させる。またフアインチユーニン
グ動作は探局動作以外の場合ｈ＝Ｈで、ｄ＝Ｈ，
ｅ＝Ｌの組合せか（組合せＡとする）、ｈ＝Ｈで、
ｄ＝Ｌ，ｅ＝Ｈの組合せ（組合せＢとする）の時
のみ出力ｄ，ｅのAFT情報を有効とし、組合せ
Ａのときはチユーニングクロツクジエネレータ回
路２１をして信号ｌを下げる方向向に働かせ組合
せＢのときはその逆に働かせ、Ａ，Ｂ以外の組合
せを無効とする動作である。 In this way, the search operation stops every time a TV signal is captured, so when starting the search operation next time, turn on the search trigger switch 27, set i=+B, and then adjust the tuning voltage m until the TV signal is captured. raise. The operation when a TV signal is captured is as described above, and the search trigger switch 27 is activated each time.
When you turn on and apply a trigger input that sets i=+B, the tuning voltage m rises to the maximum voltage in the UHF band and then stops.As a result, the station searching operation stops and the tuning voltage signal l
Set the preset control circuit 20 to the minimum voltage for the lowest channel of the VHF-LOW band.
starts to move from station searching operation to fine tuning operation. In other words, the AFT control circuit 19 and preset control circuit 20 operate in two ways: station searching operation and fine tuning operation.
When station searching is in progress, d=L, e=H→d
= H, e = L, the AFT information changes, and if h = H during this change period, the circuits 19 and 20 validate the AFT information d and e and stop the station searching operation, and the fine inch user Move on to the cleaning operation. If the relationship between the signals d, e, and h is other than this, the AFT information d and e are invalidated and the station searching operation is continued, resulting in an increase in the signal l. In addition, in the case of fine inch euning operation other than station searching operation, h=H, d=H,
The combination e=L (set as combination A), h=H,
The AFT information of outputs d and e is valid only in the combination of d=L and e=H (combination B), and in the case of combination A, the tuning clock generator circuit 21 is used to lower the signal l. This is an operation that works in the opposite direction and works in the opposite direction for combination B, making combinations other than A and B invalid.
ところで、今、切替スイツチ２８は探局モード
に接続され、信号ｌは最小でバンドがVHF―
LOWに設定され、フアインチユーニング動作に
回路１９，２０が入つた時、信号ｌが最小で電子
チユーナ１１がテレビ信号を受信可能なわけであ
るから、この直後ｈ，ｄ，ｅの信号の組合せは
Ａ，Ｂどちらかの組合せとなり組合せＢの場合は
信号ｌを上昇させるが、組合せＡの場合は信号ｌ
を最低電圧より下げる方向に働き、結果として最
大電圧になり、バンドはVHF―LOWからUHF
に変化する。そのため次に探局モードの状態でト
リガスイツチ２７がオンになり、ｉ＝＋Ｂのトリ
ガで回路２０がトリガされても、信号ｌが最大で
バンドがUHFとなつているため、探局動作の停
止→バンド＝VHF−LOW，ｌ＝最小→電子チユ
ーナ１１がVHF―LOWのあるチヤンネルをとら
える→ｄ，ｅ，ｈ組合せＡとなる→ｌ＝最大、バ
ンド＝UHFという動作となり結局何度探局トリ
ガ信号を加えてもUHF→VHF―LOWに探局を
実施することができないという欠点があつた。 By the way, the changeover switch 28 is now connected to the search mode, and the signal l is at its minimum and the band is VHF-
When the circuits 19 and 20 are set to LOW and the circuits 19 and 20 enter the fine tune operation, the signal l is at its minimum and the electronic tuner 11 can receive the television signal, so immediately after this, the signals h, d, and e are The combination is either A or B. In the case of combination B, the signal l increases, but in the case of combination A, the signal l increases.
works in the direction of lowering the voltage below the minimum voltage, resulting in the maximum voltage, and the band changes from VHF-LOW to UHF.
Changes to Therefore, even if the trigger switch 27 is turned on next time in the search mode and the circuit 20 is triggered by the trigger of i=+B, the search operation will stop because the signal l is at its maximum and the band is UHF. → Band = VHF-LOW, l = minimum → Electronic tuner 11 catches a certain channel of VHF-LOW → d, e, h combination becomes A → l = maximum, band = UHF, and in the end, how many times is the search trigger The drawback was that even if a signal was added, it was not possible to search from UHF to VHF-LOW.
したがつて、この発明の目的は、自動探局動作
がUHFバンドで同調電圧が最大に達した後、探
局動作が停止しバンドがVHF―LOWバンドに変
化し同調電圧が最低に設定される自動探局操置と
VHF―LOWバンドにおいて同調電圧が最低付近
でVHF―LOWバンドのテレビ信号が受信できる
電子チユーナおよび中間周波信号処理回路を具備
している探局装置において、最低の同調電圧で受
信できるVHF―LOWバンドのテレビ局が放送
中、自動探局動作がUHFバンドの最大同調電圧
に達した後、バンドが確実にVHF―LOWに変化
し同調電圧を最低に設定でき次に自動探局動作を
開始させた時、VHF―LOWバンドの最低同調電
圧から自動探局できるようにしたテレビジヨン受
像機の探局装置を提供することである。 Therefore, the purpose of this invention is to set the automatic station searching operation to the lowest tuning voltage after the tuning voltage reaches the maximum in the UHF band, the station searching operation stops, the band changes to the VHF-LOW band, and the tuning voltage is set to the lowest level. Automatic station search and operation
In the VHF-LOW band, the VHF-LOW band can receive television signals at the lowest tuning voltage in a station search device equipped with an electronic tuner and an intermediate frequency signal processing circuit that can receive TV signals in the VHF-LOW band at a tuning voltage near the lowest. When the TV station is broadcasting, after the automatic station search operation reaches the maximum tuning voltage of the UHF band, the band will definitely change to VHF-LOW and the tuning voltage can be set to the lowest value.The next time you start the automatic station search operation. To provide a station searching device for a television receiver that can automatically search from the lowest tuning voltage of the VHF-LOW band.
この発明のテレビジヨン受像機の探局装置は、
同調電圧の変化に従つてVHF―LOWバンドの最
低チヤンネルからUHFバンドの最高チヤンネル
まで順次選局しかつUHFバンドの最高チヤンネ
ルに達した次にはVHF―LOWバンドの最低チヤ
ンネルを選局しVHF―LOWバンドの最低チヤン
ネルに達した次にはUHFバンドの最高チヤンネ
ルを選局するテレビジヨン受像機の探局装置にお
いて、前記同調電圧が供給され選局チヤンネルが
制御される電子チユーナと、この電子チユーナの
出力電圧を処理する中間周波増幅処理回路と、こ
の中間周波増幅処理回路の中間周波出力信号の周
波数と所定中間周波数との差を検出するAFT検
波回路と、前記中間周波増幅処理回路の検波出力
信号がテレビ信号であることを判断するテレビ信
号検出回路と、前記同調電圧をVHF―LOWバン
ドの最低チヤンネル用の最小電圧からUHFバン
ドの最高チヤンネル用の最大電圧まで順次変化さ
せて自動探局し前記AFT検波回路の出力と前記
テレビ信号検出回路の出力とに応じてテレビ信号
受信時に探局を停止するとともにUHFバンドの
最高チヤンネル用の最大電圧に達すると探局動作
を停止しかつVHF―LOWバンドの最低チヤンネ
ル用の最小電圧に設定して自動探局を終了しその
後は前記AFT検波回路の出力によりフアインチ
ユーニング制御される通常選局を行う自動探局処
理回路と、使用者の操作によつてこの自動探局処
理回路に探局スタート信号を供給して自動探局動
作を開始させる探局トリガスイツチと、使用者の
操作によつて前記探局処理回路の動作を自動探局
動作と通常選局動作とに切替える切替スイツチ
と、前記切替スイツチが自動探局動作側に切替え
られておりかつ自動探局を終了してVHF―LOW
バンドの最低チヤンネル用の最小電圧に設定され
ている状態のときに前記AFT検波回路の出力を
前記自動探局処理回路に供給することを禁止する
規制回路とを備えたことを特徴とするものであ
る。 The station searching device for a television receiver of this invention includes:
As the tuning voltage changes, tune in from the lowest channel of the VHF-LOW band to the highest channel of the UHF band, and when the highest channel of the UHF band is reached, tune to the lowest channel of the VHF-LOW band, and then tune to the lowest channel of the VHF-LOW band. In a television receiver's search device that selects the highest channel of the UHF band after reaching the lowest channel of the LOW band, there is an electronic tuner to which the tuning voltage is supplied to control the channel selection, and this electronic tuner. an intermediate frequency amplification processing circuit that processes the output voltage of the intermediate frequency amplification processing circuit; an AFT detection circuit that detects the difference between the frequency of the intermediate frequency output signal of the intermediate frequency amplification processing circuit and a predetermined intermediate frequency; and a detection output of the intermediate frequency amplification processing circuit. A television signal detection circuit that determines that the signal is a television signal, and automatic station searching by sequentially changing the tuning voltage from the minimum voltage for the lowest channel of the VHF-LOW band to the maximum voltage for the highest channel of the UHF band. Depending on the output of the AFT detection circuit and the output of the TV signal detection circuit, the station search is stopped when a TV signal is received, and when the maximum voltage for the highest channel of the UHF band is reached, the station search operation is stopped and the VHF-LOW An automatic station searching processing circuit that completes automatic station searching by setting the minimum voltage for the lowest channel of the band, and then performs normal tuning controlled by the output of the AFT detection circuit, and a user operation. a search trigger switch that supplies a search start signal to the automatic station search processing circuit to start the automatic station search operation; and a search trigger switch that starts the automatic station search operation by supplying a search start signal to the automatic station search processing circuit; and a changeover switch that switches between normal station selection operation, and the changeover switch is switched to the automatic station search operation side and the automatic station search is ended and VHF-LOW is selected.
and a regulation circuit that prohibits the output of the AFT detection circuit from being supplied to the automatic station search processing circuit when the voltage is set to the minimum voltage for the lowest channel of the band. be.
この発明の一実施例を第２図に示す。図におい
て、３１は第１図の回路１２〜１４，１６を含ん
だ中間周波増幅処理回路、３２は回路１９〜２５
を含んだ自動探局処理回路である。また回路１
１，１５，１７，１８，２６およびスイツチ２
７，２８は第１図と同じである。また、４１，４
４はスイツチングトランジスタ、４２，４３，４
５はそれらのベースバイアス抵抗であり、なお信
号ｉは回路３２の入出力端子と接続され探局動作
中はＨ、それ以外はＬである。トランジスタ４
１，４４を含む規制回路Ｑは、ｉ＝Ｌ，ｊ＝Ｈの
時（すなわち探局モードで探局動作以外のとき）
のみトランジスタ４１をスイツチング（オン）す
るアンドゲートである。またｒはAFT検波回路
１５をいわゆるAFTオフにする信号である。こ
の場合、規制回路Ｑによつてｒ＝Ｌになれば、
AFT検波出力ｂはAFT―UP，DOWN信号発生
回路１８の設定電圧VL，VHとVL＜ｂ＜VHに設定
される。次に回路動作について説明する。従来例
で説明した条件、すなわちアンテナ入力にVHF
―LOWバンドで同調電圧ｍが最低で受信可能な
テレビ信号が入力されている状態で切替スイツチ
２８がオンになり、ｊ＝＋Ｂの状態でさらにトリ
ガスイツチ２７が瞬時オンとなつてｉ＝＋Ｂに瞬
時になり自動探局処理回路３２を探局状態にトリ
ガする。これにより信号ｌ、同調電圧ｍは上昇し
テレビ信号をとらえては停止するがその都度ｉ＝
＋Ｂのパルスを加えれば、探局動作となる。回路
３２の信号ｉが加わる端子は入出力端子となつて
おり探局中はｉ＝Ｈであり、しかもｊ＝Ｈのた
め、トランジスタ４１はオフ、したがつてｒ＝Ｈ
となり、AFT検波回路１５は信号ａに対する
AFT検波信号ｂを出力する。同調電圧ｍがUHF
の最大に達している時、先に説明したように探局
動作は停止し、ｌ，ｍ＝最低、バンド＝VHF―
LOWに設定され、これによりｉ＝Ｌに変化する。
この時、規制回路Ｑの入力ｊ，ｉはｊ＝Ｈ，ｉ＝
Ｌとなるためトランジスタ４１はオンとなり、ｒ
＝Ｌとなるので、VL＜ｂ＜VHとなる。したがつ
てVHF―LOWバンドの最小の同調電圧ｍでテレ
ビ信号(11)を受信しても、回路３２はｈ＝Ｈになつ
ているがAFT情報ｄ，ｅがＨとなり伝達されな
い。このため、ｌ，ｍが最小→最大、バンドが
VHF―LOW→UHFに変化することはない。つ
まり次に探局トリガを加えればVHF―LOWバン
ドの同調電圧ｍが最低値から探局されることとな
る。 An embodiment of this invention is shown in FIG. In the figure, 31 is an intermediate frequency amplification processing circuit including the circuits 12 to 14 and 16 in FIG. 1, and 32 is the circuit 19 to 25.
This is an automatic station search processing circuit that includes Also circuit 1
1, 15, 17, 18, 26 and switch 2
7 and 28 are the same as in FIG. Also, 41,4
4 is a switching transistor, 42, 43, 4
Reference numeral 5 designates their base bias resistors, and the signal i is connected to the input/output terminal of the circuit 32 and is H during the station searching operation and L otherwise. transistor 4
The regulation circuit Q including 1 and 44 operates when i=L and j=H (i.e., when station search mode is not in operation)
This is an AND gate that only switches (turns on) the transistor 41. Further, r is a signal for turning off the AFT detection circuit 15. In this case, if r=L due to the regulation circuit Q, then
The AFT detection output b is set to the set voltages V L and V H of the AFT-UP and DOWN signal generation circuit 18 such that V L < b < V H . Next, the circuit operation will be explained. The conditions explained in the conventional example, that is, VHF at the antenna input.
- The selector switch 28 is turned on when a receivable TV signal is input with the lowest tuning voltage m in the LOW band, and when j = +B, the trigger switch 27 is turned on instantaneously and i = +B. The automatic station search processing circuit 32 is instantly triggered to the station search state. As a result, the signal l and the tuning voltage m rise, catch the TV signal, and then stop, but each time i=
Adding a +B pulse will result in station searching operation. The terminal to which the signal i of the circuit 32 is applied is an input/output terminal, and during station searching, i=H, and since j=H, the transistor 41 is off, so r=H.
Therefore, the AFT detection circuit 15 detects the signal a for the signal a.
Outputs AFT detection signal b. Tuning voltage m is UHF
When the maximum is reached, the search operation stops as explained earlier, l, m = minimum, band = VHF
It is set to LOW, which changes i=L.
At this time, the inputs j and i of the regulation circuit Q are j=H, i=
Since it becomes L, the transistor 41 turns on, and r
=L, so V L < b < V H. Therefore, even if the television signal (11) is received at the minimum tuning voltage m of the VHF-LOW band, h=H in the circuit 32, but the AFT information d, e becomes H and is not transmitted. Therefore, l and m are minimum → maximum, and the band is
There is no change from VHF-LOW to UHF. In other words, if a search trigger is applied next time, the VHF-LOW band tuning voltage m will be searched from the lowest value.
以上のように、この発明のテレビジヨン受像機
の探局装置は、同調電圧を変えて種々の放送電波
を受信できる電子チユーナと、中間周波数と設定
周波数との差を検波するAFT検波回路と、中間
検波増幅回路と映像検波回路から出力される映像
信号と受像機のフライバツクパルス信号によつて
テレビ信号と判断するテレビ信号検出回路と、使
用者によつてトリガされる探局スタート信号によ
り出力電圧が滑らかに上下し、その出力電圧を、
前記電子チユーナの同調電圧として使用し、その
出力を上下することにより、放送電波を探局して
テレビ信号を捕えると、前記テレビ信号検出回路
から出力される探局ストツプ信号とAFT検波回
路の出力電圧によつて最適同調電圧を得て出力電
圧が一定になり、最終的には放送電波を受信した
状態を維持するような出力電圧を発生する回路と
その出力電圧を記憶する自動探局処理回路を具備
したテレビジヨン受像機の探局装置において、前
記電子チユーナがVHFのLOWバンドでしかも同
調電圧の最低付近でVHFのLOWチヤンネルの最
低チヤンネルの放送信号が受信でき、前記探局動
作がUHFの最大同調電圧で探局動作が停止する
機能になつている場合、同調電圧の最大かつバン
ドがUHFの状態で探局スタート信号を加えた時
バンドがVHFのLOWに同調電圧が最大から最低
に変化するように、探局モードで探局中以外の時
にAFT検波回路のAFT情報をオフにする回路を
設けたため、探局スタート操作により確実に最低
同調電圧のVHF―LOWバンドから自動探局でき
るという効果がある。 As described above, the station searching device for a television receiver of the present invention includes an electronic tuner that can receive various broadcast waves by changing the tuning voltage, an AFT detection circuit that detects the difference between an intermediate frequency and a set frequency, A TV signal detection circuit that determines that it is a TV signal based on the video signal output from the intermediate detection amplifier circuit and the video detection circuit and the flyback pulse signal of the receiver, and a search start signal that is triggered by the user. The voltage rises and falls smoothly, and the output voltage
It is used as the tuning voltage of the electronic tuner, and by raising and lowering its output, when the broadcast radio waves are searched and a TV signal is captured, the search stop signal output from the TV signal detection circuit and the output of the AFT detection circuit are generated. A circuit that generates an output voltage that obtains the optimal tuning voltage depending on the voltage, makes the output voltage constant, and ultimately maintains the condition of receiving broadcast radio waves, and an automatic station search processing circuit that stores the output voltage. In the station searching device for a television receiver, the electronic tuner is capable of receiving the broadcast signal of the lowest channel of the VHF LOW channel in the VHF LOW band and near the lowest tuning voltage, and the station searching operation is performed in the UHF LOW band. If the function is such that the search operation stops at the maximum tuning voltage, when the search start signal is applied when the tuning voltage is maximum and the band is UHF, the tuning voltage will change from the maximum to the minimum when the band becomes VHF LOW. In order to do this, we have installed a circuit that turns off the AFT information of the AFT detection circuit when not searching in station search mode, so automatic station searching can be performed reliably from the VHF-LOW band with the lowest tuning voltage by the search start operation. effective.
第１図は従来例の回路図、第２図はこの発明の
一実施例の回路図である。
１１…電子チユーナ、１５…AFT検波回路、
１７…テレビ信号検出回路、２７…探局トリガス
イツチ、３１…中間周波増幅処理回路、３２…自
動探局処理回路、Ｑ…規制回路。
FIG. 1 is a circuit diagram of a conventional example, and FIG. 2 is a circuit diagram of an embodiment of the present invention. 11...Electronic tuner, 15...AFT detection circuit,
17... Television signal detection circuit, 27... Search trigger switch, 31... Intermediate frequency amplification processing circuit, 32... Automatic search processing circuit, Q... Regulation circuit.
Claims (1)
の最低チヤンネルからUHFバンドの最高チヤン
ネルまで順次選局しかつUHFバンドの最高チヤ
ンネルに達した次にはVHF―LOWバンドの最低
チヤンネルを選局しVHF―LOWバンドの最低チ
ヤンネルに達した次にはUHFバンドの最高チヤ
ンネルを選局するテレビジヨン受像機の探局装置
において、前記同調電圧が供給され選局チヤンネ
ルが制御される電子チユーナと、この電子チユー
ナの出力電圧を処理する中間周波増幅処理回路
と、この中間周波増幅処理回路の中間周波出力信
号の周波数と所定中間周波数との差を検出する
AFT検波回路と、前記中間周波増幅処理回路の
検波出力信号がテレビ信号であることを判断する
テレビ信号検出回路と、前記同調電圧をVHF―
LOWバンドの最低チヤンネル用の最小電圧から
UHFバンドの最高チヤンネル用の最大電圧まで
順次変化させて自動探局し前記AFT検波回路の
出力と前記テレビ信号検出回路の出力とに応じて
テレビ信号受信時に探局を停止するとともに
UHFバンドの最高チヤンネル用の最大電圧に達
すると探局動作を停止しかつVHF―LOWバンド
の最低チヤンネル用の最小電圧に設定して自動探
局を終了しその後は前記AFT検波回路の出力に
よりフアインチユーニング制御される通常選局を
行う自動探局処理回路と、使用者の操作によつて
この自動探局処理回路に探局スタート信号を供給
して自動探局動作を開始させる探局トリガスイツ
チと、使用者の操作によつて前記探局処理回路の
動作を自動探局動作と通常選局動作とに切替える
切替スイツチと、前記切替スイツチが自動探局動
作側に切替えられておりかつ自動探局を終了して
VHF―LOWバンドの最低チヤンネル用の最小電
圧に設定されている状態のときに前記AFT検波
回路の出力を前記自動探局処理回路に供給するこ
とを禁止する規制回路とを備えたことを特徴とす
るテレビジヨン受像機の探局装置。1 As the tuning voltage changes, tune in from the lowest channel of the VHF-LOW band to the highest channel of the UHF band, and when the highest channel of the UHF band is reached, select the lowest channel of the VHF-LOW band, and then tune to the lowest channel of the VHF-LOW band. - In a television receiver's search device that selects the highest channel of the UHF band after reaching the lowest channel of the LOW band, the electronic tuner to which the tuning voltage is supplied to control the channel selection, and this electronic An intermediate frequency amplification processing circuit that processes the output voltage of the tuner, and detecting the difference between the frequency of the intermediate frequency output signal of this intermediate frequency amplification processing circuit and a predetermined intermediate frequency.
an AFT detection circuit; a television signal detection circuit that determines that the detected output signal of the intermediate frequency amplification processing circuit is a television signal;
From the minimum voltage for the lowest channel of the LOW band
Automatically searches for stations by sequentially changing the voltage up to the maximum voltage for the highest channel of the UHF band, and stops searching when a TV signal is received according to the output of the AFT detection circuit and the output of the TV signal detection circuit.
When the maximum voltage for the highest channel of the UHF band is reached, the station search operation is stopped and the automatic station search is terminated by setting the voltage to the minimum voltage for the lowest channel of the VHF-LOW band. An automatic station search processing circuit that performs normal station selection under inch-unning control, and a station search trigger that supplies a search start signal to this automatic station search processing circuit and starts automatic station search operation according to the user's operation. a switch, a changeover switch for switching the operation of the station search processing circuit between an automatic station search operation and a normal station selection operation according to a user's operation; Finish the search
and a regulation circuit that prohibits the output of the AFT detection circuit from being supplied to the automatic station search processing circuit when the voltage is set to the minimum voltage for the lowest channel of the VHF-LOW band. A station searching device for television receivers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13045481A JPS5831612A (en) | 1981-08-19 | 1981-08-19 | Station search device for television receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13045481A JPS5831612A (en) | 1981-08-19 | 1981-08-19 | Station search device for television receiver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5831612A JPS5831612A (en) | 1983-02-24 |
| JPH0125447B2 true JPH0125447B2 (en) | 1989-05-17 |
Family
ID=15034616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13045481A Granted JPS5831612A (en) | 1981-08-19 | 1981-08-19 | Station search device for television receiver |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5831612A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4776038A (en) * | 1987-01-21 | 1988-10-04 | Rca Licensing Corporation | Automatic air/cable mode selection apparatus for a television tuner |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51140506A (en) * | 1975-05-30 | 1976-12-03 | Toshiba Corp | Auto-tuning device |
| JPS5643824A (en) * | 1979-09-19 | 1981-04-22 | Hitachi Ltd | Channel selector |
-
1981
- 1981-08-19 JP JP13045481A patent/JPS5831612A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51140506A (en) * | 1975-05-30 | 1976-12-03 | Toshiba Corp | Auto-tuning device |
| JPS5643824A (en) * | 1979-09-19 | 1981-04-22 | Hitachi Ltd | Channel selector |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5831612A (en) | 1983-02-24 |
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