ARRANGEMENT FOR READING INFORMATION FROM A TRACK ON A RECORD CARRIER

摘要

An arrangement for reading out an information signal from a magnetic record carrier is disclosed. The arrangement comprises a read head having a magneto-resistive (MR) element (Rm1 with a first terminal (3) connected to a first point (13) of constant potential and with a second terminal (4), a bias-current generator (2; 210, T20) having an output (5) for supplying a bias-current to the MR element and an amplifier circuit (1) having a first terminal (6) coupled to the output (5) of the bias-current generator (2) and a second terminal (7) coupled to the second terminal (4) of the magneto-resistive head (Rm1) so as to form a series arrangement of the bias-current generator, the amplifier circuit and the magneto-resistive element. At an output terminal (8) the information signal is available. The amplifier circuit (1) comprises a MOS transistor (T1) connected between the ouptut terminal (8) and the second terminal (7). A feedback circuit having a low cut-off frequency (F1; 206, C1) provides a bias voltage to the gate of the MOS transistor (T1) and forces the entire bias current of the bias current generator (2) to flow through the MR element. The arrangement is balanced and the cut-off capacitors C1 and C2 of the two individual amplifiers (1; 61) are cross-coupled to reduce noise.