JPH0320537U - - Google Patents
Info
- Publication number
- JPH0320537U JPH0320537U JP8132089U JP8132089U JPH0320537U JP H0320537 U JPH0320537 U JP H0320537U JP 8132089 U JP8132089 U JP 8132089U JP 8132089 U JP8132089 U JP 8132089U JP H0320537 U JPH0320537 U JP H0320537U
- Authority
- JP
- Japan
- Prior art keywords
- signal
- circuit
- intermediate frequency
- phase detection
- frequency 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
- 238000001514 detection method Methods 0.000 claims description 10
- 230000010355 oscillation Effects 0.000 claims description 8
- 238000010586 diagram Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
Landscapes
- Television Receiver Circuits (AREA)
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
Description
第１図はこの考案の一実施例のブロツク回路図
、第２図は従来のＡＦＴ回路のブロツク回路図で
ある。
１……映像中間周波変換回路、３……映像搬送
波増幅回路、４……基準中間周波信号発振回路、
５，８……位相検波回路、６……局部発振回路、
７……第２の中間周波信号発振回路、９……低域
通過フイルタ、１０……フイードバツク・ループ
回路。なお、各図中、同一符号は同一、または相
当部分を示す。
FIG. 1 is a block circuit diagram of an embodiment of this invention, and FIG. 2 is a block circuit diagram of a conventional AFT circuit. 1... Video intermediate frequency conversion circuit, 3... Video carrier amplification circuit, 4... Reference intermediate frequency signal oscillation circuit,
5, 8... Phase detection circuit, 6... Local oscillation circuit,
7... Second intermediate frequency signal oscillation circuit, 9... Low pass filter, 10... Feedback loop circuit. In each figure, the same reference numerals indicate the same or corresponding parts.
Claims (1)
変換して映像中間周波信号に変換し、この映像中
間周波信号から抽出した映像搬送波信号を第１の
位相検波回路で基準中間周波信号と比較して位相
検波を行い、この位相検波信号を局部発振回路に
負帰還して上記位相検波信号が零となるように局
部発信信号の周波数を制御するように構成された
ＡＦＴ回路において、第２の中間周波信号発信回
路と、この回路から出力される第２の中間周波信
号と上記抽出された映像搬送波信号とを入力とす
る第２の位相検波回路と、この回路から出力され
る位相検波信号から映像信号による変調成分を除
去する低域通過フイルタとで構成され、上記低域
通過フイルタの出力信号を上記第２の中間周波信
号発振回路に負帰還して当該位相検波信号が零と
なるように制御するフイードバツク・ループ回路
を備え、この第２の中間周波発振回路から出力さ
れる第２の中間周波信号を上記第１の位相検波回
路に入力して上記基準中間周波信号と位相検波を
行う構成としたことを特徴とするＡＦＴ回路。 A television broadcast signal is frequency-converted using a local oscillation signal to convert it into a video intermediate frequency signal, and a video carrier signal extracted from this video intermediate frequency signal is compared with a reference intermediate frequency signal in a first phase detection circuit to perform phase detection. In the AFT circuit configured to control the frequency of the local oscillation signal so that the phase detection signal becomes zero by negative feedback of the phase detection signal to the local oscillation circuit, a second intermediate frequency signal is generated. a second phase detection circuit which receives as input the second intermediate frequency signal outputted from this circuit and the extracted video carrier signal; and modulation of the phase detection signal outputted from this circuit with a video signal. a low-pass filter that removes the component, and a feedback circuit that controls the output signal of the low-pass filter so that the output signal of the low-pass filter is negatively fed back to the second intermediate frequency signal oscillation circuit so that the phase detection signal becomes zero; A loop circuit is provided, and a second intermediate frequency signal output from the second intermediate frequency oscillation circuit is input to the first phase detection circuit to perform phase detection with the reference intermediate frequency signal. Characteristic AFT circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8132089U JPH0320537U (en) | 1989-07-10 | 1989-07-10 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8132089U JPH0320537U (en) | 1989-07-10 | 1989-07-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0320537U true JPH0320537U (en) | 1991-02-28 |
Family
ID=31627158
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8132089U Pending JPH0320537U (en) | 1989-07-10 | 1989-07-10 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0320537U (en) |
-
1989
- 1989-07-10 JP JP8132089U patent/JPH0320537U/ja active Pending
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