JPH0346236U - - Google Patents
Info
- Publication number
- JPH0346236U JPH0346236U JP10542289U JP10542289U JPH0346236U JP H0346236 U JPH0346236 U JP H0346236U JP 10542289 U JP10542289 U JP 10542289U JP 10542289 U JP10542289 U JP 10542289U JP H0346236 U JPH0346236 U JP H0346236U
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- control means
- electric field
- field strength
- signal
- 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
- 230000005684 electric field Effects 0.000 claims description 5
- 238000001514 detection method Methods 0.000 claims 4
- 230000010355 oscillation Effects 0.000 claims 2
- 238000010586 diagram Methods 0.000 description 3
- 230000005236 sound signal Effects 0.000 description 1
Landscapes
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
- Circuits Of Receivers In General (AREA)
Description
第１図は、この考案による自動周波数微調装置
の機能ブロツク図、第２図は、この考案による自
動周波数微調装置が適用された衛星放送システム
の受信機の構成ブロツク図、第３図は、この考案
による自動周波数微調装置の基本動作、処理の流
れを示すフローチヤートである。
１……アンテナ、２……ＲＦ増幅器、３……混
合器、４……局部発振器、５……復調器、６……
映像信号処理器、７……電界強度検出器、８……
ＰＣＭ音声信号処理器、９……Ｄ／Ａ変換器、１
０……ＬＰＦ、１１……直流電圧検出器、１２…
…同期信号検出器、１３……プロセツサ、１４…
…基準発振器、１５……位相比較器、１６……１
／Ｎ分周器、１７……フイルタ。
Fig. 1 is a functional block diagram of the automatic frequency fine tuning device according to this invention, Fig. 2 is a configuration block diagram of a receiver of a satellite broadcasting system to which the automatic frequency fine tuning device according to this invention is applied, and Fig. 3 is a functional block diagram of the automatic frequency fine tuning device according to this invention. This is a flowchart showing the basic operation and processing flow of the invented automatic frequency fine tuning device. 1... Antenna, 2... RF amplifier, 3... Mixer, 4... Local oscillator, 5... Demodulator, 6...
Video signal processor, 7... Electric field strength detector, 8...
PCM audio signal processor, 9...D/A converter, 1
0...LPF, 11...DC voltage detector, 12...
...Synchronization signal detector, 13...Processor, 14...
...Reference oscillator, 15...Phase comparator, 16...1
/N frequency divider, 17...filter.
Claims (1)
器により分周した分周信号と基準発振器からの基
準信号との位相比較結果に基づいて前記局部発振
器の局発周波数を制御するＰＬＬ回路手段と、 入力信号の復調信号の直流成分レベルを検出す
る直流レベル検出手段と、 前記直流レベル検出手段で得られた直流レベル
に応じて前記１／Ｎ分周器の分周比を制御する第
１の制御手段と、 前記入力信号の同期外れを検出する同期外れ検
出手段と、 前記同期外れが検出される前記局発周波数の上
限周波数の下限周波数とを求め、前記上限周波数
と下限周波数とに基づいて適正な周波数を定め、
この適正周波数により前記分周比を制御する第２
の制御手段と、 前記復調信号から電界強度を検出する電界強度
検出手段と、 前記電界強度検出手段で検出された電界強度が
所定の閾値以上のとき前記第１の制御手段を駆動
せしめ、前記閾値以下のとき前記第２の制御手段
を駆動せしめる第３の制御手段とを備えて成るこ
とを特徴とする自動周波数微調装置。[Claims for Utility Model Registration] Based on the phase comparison result between the frequency-divided signal obtained by dividing the local frequency signal from the local oscillator by a 1/N frequency divider and the reference signal from the reference oscillator, PLL circuit means for controlling the oscillation frequency; DC level detection means for detecting the DC component level of the demodulated signal of the input signal; a first control means for controlling a frequency division ratio; an out-of-synchronization detection means for detecting an out-of-synchronization of the input signal; and a lower limit frequency of the upper limit frequency of the local oscillation frequency at which the out-of-synchronization is detected; Determine an appropriate frequency based on the upper limit frequency and lower limit frequency,
A second circuit that controls the frequency division ratio based on this appropriate frequency.
a control means; an electric field strength detection means for detecting electric field strength from the demodulated signal; and a control means for driving the first control means when the electric field strength detected by the electric field strength detection means is equal to or higher than a predetermined threshold; An automatic frequency fine tuning device comprising: third control means for driving the second control means in the following cases.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10542289U JPH0346236U (en) | 1989-09-11 | 1989-09-11 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10542289U JPH0346236U (en) | 1989-09-11 | 1989-09-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0346236U true JPH0346236U (en) | 1991-04-30 |
Family
ID=31654184
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10542289U Pending JPH0346236U (en) | 1989-09-11 | 1989-09-11 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0346236U (en) |
-
1989
- 1989-09-11 JP JP10542289U patent/JPH0346236U/ja active Pending
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