JPS6320679U - - Google Patents
Info
- Publication number
- JPS6320679U JPS6320679U JP11211286U JP11211286U JPS6320679U JP S6320679 U JPS6320679 U JP S6320679U JP 11211286 U JP11211286 U JP 11211286U JP 11211286 U JP11211286 U JP 11211286U JP S6320679 U JPS6320679 U JP S6320679U
- Authority
- JP
- Japan
- Prior art keywords
- signal
- apl
- intermediate frequency
- gain
- gain control
- 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
- 238000001514 detection method Methods 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 claims 2
- 238000010586 diagram Methods 0.000 description 2
- 230000005684 electric field Effects 0.000 description 1
Landscapes
- Television Receiver Circuits (AREA)
Description
第１図はこの考案の一実施例を示す回路図、第
２図は従来の自動周波数制御回路を示す回路図で
ある。
２１……第２の周波数変換器、２２……自動利
得制御回路、２３……ＦＭ復調回路、２７……マ
イコン、２９……受信電界判定比較器、３０……
ＡＰＬ検出回路。
FIG. 1 is a circuit diagram showing an embodiment of this invention, and FIG. 2 is a circuit diagram showing a conventional automatic frequency control circuit. 21... Second frequency converter, 22... Automatic gain control circuit, 23... FM demodulation circuit, 27... Microcomputer, 29... Received electric field determination comparator, 30...
APL detection circuit.
Claims (1)
る周波数変換手段と、前記第１の中間周波信号を
入力しこれより利得制御電圧を得て、上記第１の
中間周波信号の利得を所定の値に調節し第２の中
間周波信号として出力する自動利得制御手段と、
前記第２の中間周波信号をＦＭ復調する復調手段
と、この復調手段の出力する復調信号より平均輝
度レベル（ＡＰＬ）を検出するＡＰＬ検出手段と
、前記利得制御電圧と基準電圧とを比較する比較
手段と、前記ＡＰＬ検出手段の出力するＡＰＬ信
号及び前記比較手段の出力する比較結果信号の供
給を受け、前記利得制御電圧が基準電圧を上回る
場合に前記ＡＰＬ信号に応じて前記周波数変換手
段を制御する制御手段とを具備することを特徴と
する自動周波数制御回路。 a frequency conversion means for converting a high frequency video signal into a first intermediate frequency signal; inputting the first intermediate frequency signal and obtaining a gain control voltage therefrom; and controlling the gain of the first intermediate frequency signal to a predetermined value. automatic gain control means for adjusting the gain and outputting it as a second intermediate frequency signal;
demodulation means for FM demodulating the second intermediate frequency signal; APL detection means for detecting an average luminance level (APL) from a demodulated signal output from the demodulation means; and a comparison for comparing the gain control voltage and a reference voltage. means, receiving an APL signal output from the APL detection means and a comparison result signal output from the comparison means, and controlling the frequency conversion means in accordance with the APL signal when the gain control voltage exceeds a reference voltage. An automatic frequency control circuit characterized by comprising: a control means for controlling the frequency;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11211286U JPS6320679U (en) | 1986-07-23 | 1986-07-23 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11211286U JPS6320679U (en) | 1986-07-23 | 1986-07-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6320679U true JPS6320679U (en) | 1988-02-10 |
Family
ID=30992674
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11211286U Pending JPS6320679U (en) | 1986-07-23 | 1986-07-23 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6320679U (en) |
-
1986
- 1986-07-23 JP JP11211286U patent/JPS6320679U/ja active Pending
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