Measuring impulse response and nonlinear distortions using exponential frequency-modulated signals

Yinjie Jia – Pengfei Xu

   Exponential Frequency-Modulated (EFM) signals, characterized by their exponentially changing instantaneous frequency, are valuable in radar, sonar, and communication systems. This paper explores the application of EFM signals for measuring impulse response and nonlinear distortions in electronic devices. The EFM signal testing method, which involves recording and analyzing the device's output in response to EFM signals, provides insights into amplitude-frequency, phase-frequency responses, and impulse response. The spectral density analysis reveals a 3 dB/octave decrease in high-frequency regions. An innovative measurement method is proposed, involving convolution with a time-reversed and amplitude-modulated EFM signal, simplifying traditional approaches. MATLAB simulations validate the method, highlighting its efficacy in comprehensive device performance assessment.

Keywords: exponential frequency modulation, impulse response, spectral density, convolution

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