Amplifier apparatus and magnetic recording and reproducing apparatus having the same

摘要

Provides a magnetic recording and reproducing apparatus having an amplified apparatus, which is switched from a recording state to a readout state based on a control signal; reads out a signal containing a servo signal by the signal readout means; and includes the amplifier apparatus for amplifying the signal with an amplifier and outputting the amplified signal; and filters the signals by the filtering means that allows high frequency part of signals to pass through with the first cutoff frequency during the first prescribed time period after the readout state has been initiated; the second cutoff frequency that is lower than the first cutoff frequency during the second prescribed time period after the first prescribed time period has passed; and the third cutoff frequency that is lower than the second cutoff frequency after the second prescribed time period has passed.