System for measuring selected parameters of electrical signals and method

Abstract

An electrical measuring system for measuring selected parameters of electrical signals derived from magnetic recording and having a frequency within a known frequency range wherein the system includes an input stage having an automatic amplifier for selectively amplifying the electrical signals to a preselected amplitude level, a first circuit which includes a digital peak detecting circuit for producing digital signals representing peak amplitude and the amplitude of the electrical signals sampled at closely spaced intervals and wherein the digital peak detecting circuit includes circuitry for sampling the preselected amplitude level electrical signals at a frequency which is less than the frequency of the electrical signals, a second circuit which includes a first phase-locked loop circuit, a frequency dividing circuit and a second phase-locked loop circuit for producing an output signal representing the frequency of a remnant signal in the electrical signals which is applied to the digital peak detecting circuit for producing a digital signal representing the remnant signal magnitude, a third and fourth stage for producing direct current voltage signals representing the power magnitude of noise spectra and the DC content of a pulse train for deriving from the pulse widths of the electrical signals, respectively, and for applying the same to the digital peak detecting circuit to produce a digital representation thereof is shown. A method for processing electrical signals to produce digital representations of the amplitude, read-over-write ratio, signal-to-noise ratio and the average pulse widths thereof is shown.