JPS61195554U - - Google Patents

Description

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本考案の一実施例を示す回路ブロツク
図、第２図は同要部波形説明図であり、第３図は
従来回路の回路ブロツク図、第４図は同要部波形
説明図であり、第５図は本考案のヘツド配置を示
す模式的説明図を、それぞれ示す。 １１……第１極性反転回路、１２……第２極性
反転回路、１……（第１）位相比較回路、ＤＭ…
…ドラムモータ、ＳＡ，ＳＢ……標準録再ビデオ
ヘツド、ＬＡ，ＡＢ……長時間録再ビデオヘツド
。 Fig. 1 is a circuit block diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram of waveforms of the same main part, Fig. 3 is a circuit block diagram of a conventional circuit, and Fig. 4 is an explanatory diagram of waveforms of the main part of the same. and FIG. 5 is a schematic explanatory diagram showing the head arrangement of the present invention. 11...First polarity inversion circuit, 12...Second polarity inversion circuit, 1...(first) phase comparison circuit, DM...
...Drum motor, SA, SB...Standard recording/playback video head, LA, AB...Long time recording/playback video head.

Claims (1)

【実用新案登録請求の範囲】 アジマスを異にする標準録再ビデオヘツドに対
し逆アジマスの長時間録再ビデオヘツドを近接配
置して成るビデオテープレコーダに於て、 ヘツドドラムモータ側の位相比較回路の基準入
力側と比較入力側に、標準記録モードと長時間記
録モードとの記録モード切換に伴い入力信号の極
性を反転する第１極性切換回路と第２極性切換回
路をそれぞれ配し、前記第１極性切換回路出力を
コントロールヘツドに供給することを特徴とする
サーボ回路。[Claims for Utility Model Registration] In a video tape recorder in which a long-time recording/playback video head with an opposite azimuth is placed close to a standard recording/playback video head with a different azimuth, a phase comparison circuit on the head drum motor side. A first polarity switching circuit and a second polarity switching circuit for inverting the polarity of the input signal upon switching the recording mode between the standard recording mode and the long-term recording mode are respectively disposed on the reference input side and comparison input side of the A servo circuit characterized by supplying a unipolarity switching circuit output to a control head.