JPS5528577A - Control signal detection system - Google Patents

Abstract

PURPOSE:To avoid the effect of the dropout by detecting the bit section signals recorded in pile on the signals and the bit signals between the section signals and the memorizing the necessary bit number time. CONSTITUTION:When the heading of the sectioned data of the magnetic recording medium is detected by heading detector 25, FF1 is set by the heading detection pulse to open AND gate G1. Thus bit data signals DB1, DB2 and so on forming four bits and others are detected along with signals DH1 and DH2, bit section signal DH1 plus data start signal DS to be turned into the control signals through rectifier 27, waveform shaper 29 and others to trigger monostable multivibrator MM1 via OR gate G2. As a result, MM1 generates the pulse featuring the time longer than the time of one bit and shorter than the time of three bits to open AND gate G4, and FF2 is set by the detection signal passing through gate G1. Thus FF2 memorizes the time until detection of the next signals DH1, and accordingly the control signals are detected substantially via register RG and others at the fixed time even in case no signal DH1 and others is detected through dropout.