Magnetic pickup preamplifier

摘要

A magnetic pickup which contains both resistance and stray capacitance is terminated by a negative impedance of a kind which compensates for the stray capacitance and part of the resistance, and causes a pole to be produced at a low frequency. This results in the formation of a virtually perfect integrator. Preferably the integrator is followed by a pedestal filter for receiving the output signal of the integrator, and has a zero phase shift point at a predetermined frequency higher than the frequency of the pole and within the frequency band, and has an intermediate frequency band transfer characteristic which increases at a rate of approximately equal to the decrease in transfer characteristic of integrator.