Magnetic recording and reproducing apparatus having a drum preamplifier with improved S/N and dynamic range

摘要

A magnetic recording and reproducing apparatus amplifies a current representing a recording signal reproduced from an information signal recorded on a magnetic tape, suppresses low frequency components of the current amplified signal, then amplifies a voltage representing the suppressed signal. The voltage amplified signal is supplied from a primary winding of a rotary transformer inside a drum to a secondary winding of the rotary transformer disposed outside the drum, and then its low frequency components are emphasized. This avoids the problems of an inadequate S/N in the low frequency components of the output of a voltage amplifier, and difficulty in providing a high voltage signal from a current amplifier. The emphasized signal is supplied to one of a plurality of equalizing circuits that respectively equalize a signal reproduced at one of a plurality of frequencies. The inputs of the equalizing circuits and a terminating resistance are connected to serially located nodes of a transmission line, with higher frequency equalizing circuits disposed closer to the terminating resistance, thereby avoiding introduction of amplitude distortion in the emphasized signal due to reflection along the transmission line.