Qualifier circuit

Abstract

The present arrangement includes a circuit to receive non-differentiated pulse signals from the read circuitry of a magnetic recording medium system. These non-differentiated pulse signals are transmitted to a circuit which averages the values of the peaks of said signals, takes a predetermined percentage of that average value and produces a peak reference signal. The peak reference signal is transmitted to a comparison circuit whereat it is compared with the non-differentiated pulse signals and if the value of the peaks of the latter signals exceed the value of the peak reference signal, the comparison circuit will provide an output signal. The non-differentiated pulse signals are also transmitted to a differentiation circuit to effect a differentiation thereof and therefrom are transmitted to a zero crossover circuit. The zero crossover circuit provides a signal with a useful rising or falling edge, whose rising and falling edges occur at the zero crossovers of the differentiated signals. The output signal of the zero crossover circuit is applied to logic circuitry, which produces a qualified pulse when a rising edge of an output signal from the zero crossover circuit, occurs during the time that an output signal from the comparison circuit is present, which indicates that the pulse being considered, based on its peak value, is an intended pulse.