| 摘要 |
PURPOSE:To improve discriminating performance by comparing the peak of a pattern waveform with a reference voltage to change a stabilized state of a bistable circuit according to the comparison result, and varying the amplification factor of an amplifier or said reference voltage according to the stabilized state of the circuit. CONSTITUTION:In a magnetic ink character reader which extracts features of a pattern waveform by comparing the pattern waveform with a prescribed reference voltage, the output of a read sensor 1 for magnetic ink characters is amplified by an amplifier 2, whose output pattern waveform is compared with a peak reference voltage Vref1 by a comparator 11 to reset an F/F12 when the pattern waveform is below the voltage. When above the voltage to the contrary, the F/F12 is set to energize relay 13 and to decrease the amplification factor of said amplifier, performing AGC. Further, critical reference voltages VrefN and VrefS for obtaining N and S pulses may be varied according to the stabilized state of said F/F12. |
