| 摘要 |
PURPOSE:To effectively utilize the resolution of a D/D conversion circuit by applying A/D conversion to an RF signal selected by a switch among amplified signals of in-phase or opposite phase to a reproduced RF signal where the polarity at a recording section and a preformat section is coincident. CONSTITUTION:The RF signal is given to an amplifier circuit 1 and signals in-phase and in opposite phase to the inputted RF signal is outputted and given to a switch 6 via capacitors 2, 3. A synchronizing signal of in phase or opposite phase signal is clamped to a prescribed reference potential by a clamp circuit comprising switches 4, 5 to which a reference potential is supplied. Moreover, a timing circuit generates a gate signal corresponding to a recording section and an identification signal corresponding to the RF signal at a recording section and-outputted to an AND gate 7. The sectional logic of the re-gate signal is 1 and 0 respectively to the recording section and the preformat PF section. The identification signal is respectively 0, 1 depending whether or not the polarity for the recording section and the PF section is coincident. An output of the AND gate 7 changes over a switch 6 to given the RF signal whose polarity in the recording section is coincident with that of the PF section is given to an A/D converter 8.
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