发明名称 Video signal reproducing circuit for a video tape recorder.
摘要 <p> An apparatus for reproducing from a magnetic tape (T) first and second video signals (S&lt;Sub&gt;cv&lt;/Sub&gt;.S&lt;Sub&gt;sp&lt;/Sub&gt;) which are frequency modulated on a carrier, the first video signal having the center frequency of the carrier lower than that of the second video signal is disclosed, which includes a demodulator (3) for demodulating the first and second video signals, a first low-pass filter (4) for filtering the first video signal demod- utated by the demodulator, the first low-pass filter having a first cut-off frequency (F&lt;Sub&gt;2&lt;/Sub&gt;), a second low-pass filter (5) for filtering the second video signal demodulated by the demod- utator (3), the second low-pass filter having a second cut-off frequency (F&lt;Sub&gt;1&lt;/Sub&gt;) which is lower than the first cut-off frequency (F&lt;Sub&gt;2&lt;/Sub&gt;), a detector (20) connected prior to the demodulator (3) for detecting whether reproduced video signal is the first or second video signal and for generating a control signal in reeponse thereto and a switching circuit (6) for sypplying the cideo signals to an output terminal in accordance with the connteol signal from the detector.</p><p>There is also disclosed an apparatus for recording and reproducing a video signal, which includes a first modulator for frequency modulating a video signal with a first frequency carrier to produce a first video signal, a second modulator for frequency-modulating the video signal with a second frequency carrier to produce a second video signal, a recording head for recording the first and second video signals frequency-modulated by the first and second mod- ulafors on a magnetic tape, a reproducing head for reproducing the first and second video signals recorded on the magnetic tape, a detector for detecting whether the video signal reproduced from the magnetic tape is frequency-modulated with the first frequency carrier or with the second frequency carrier, and for generating a control signal, and a first switching circuit of selectively activating the first and second modulator in accordance with the control signal, a frequency of the carrier used in recording subsequent to reproducing being coincident with a frequency of the carrier used in the reproducing.</p>
申请公布号 EP0154221(A2) 申请公布日期 1985.09.11
申请号 EP19850101579 申请日期 1985.02.13
申请人 SONY CORPORATION 发明人 SATO, ICHITARO C/O SONY CORPORATION
分类号 H04N5/922;G11B20/02;G11B5/027;H04N5/92;H04N5/93;H04N9/79;H04N9/80;H04N9/83;H04N9/87;H04N9/89;(IPC1-7):H04N9/83 主分类号 H04N5/922
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