Patent ID: 6232760
Filing Date: 2001-05-15
Classification: G01R

Abstract:
A method for determining a transmission function of a digital measurement apparatus, comprising the steps of:at an input end within the measurement apparatus providing a calibration oscillator having a known carrier frequency which is modulated with a modulation signal to create a calibration signal to cause a line spectrum to arise within an employed frequency band within the measurement apparatus;providing in the measurement apparatus an analog-to-digital converter which creates a digitized output signal at an output from the measurement apparatus; andin a computer connected at the output of the measurement apparatus calculating the modulation signal of the calibration signal from said known carrier frequency and a known sampling frequency of the analog-to-digital converter by use of a digital FM demodulator, calculating in the computer a start frequency and a slope, as well as a beginning time and ending time of the modulation signal by means of a differentiation of an output signal of the FM demodulator, and wherein calculating from said calculation as well as from the known carrier frequency of the calibration oscillator the transmission function of the measurement apparatus.